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Bus Transit Capacity - Transportation Research Board

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1. sess 2 91 Part 2 BUS TRANSIT CAPACITY Page 2 iii Contents Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 iv Contents Transit Capacity and Quality of Service Manual 1 BUS CAPACITY BASICS OVERVIEW Bus capacity is a complex topic it deals with the movement of both people and vehicles depends on the size of the buses used and how often they operate and reflects the interaction between passenger traffic concentrations and vehicle flow It also depends on the operating policy of the service provider which normally specifies service frequencies and allowable passenger loadings Ultimately the capacities of bus routes bus lanes and bus terminals in terms of persons carried are generally limited by 1 the ability of stops or loading areas to pick up and discharge passengers 2 the number of vehicles operated and 3 the distribution of boardings and alightings along a route Part 2 of the Transit Capacity and Quality of Service Manual presents methods for calculating bus capacity and speed for a variety of facility and operating types e Chapter I introduces the basic factors and concepts that determine bus capacity e Chapter 2 discusses bus and roadway operating issues that influence bus capacity e Chapters 3 6 present capacity and speed calculation procedures for four facility and operating categories The Types of Bus Facilities and Servic
2. seen 2 35 Exhibit 2 35 Freeway Ramp Queue Bypass Concept sse 2 35 Exhibit 2 36 Freeway Ramp Queue Bypass Example Los Angeles 2 36 Exhibit 2 37 Typical Busway and HOV Lane Minimum Operating Thresholds WIE ET Petes taedetes E EE AE EEA A OER 2 36 Exhibit 2 38 General Planning Guidelines for Bus Priority Treatments Freeways 2 37 Exhibit 2 39 Bus Preferential Treatments Comparison esee 2 38 Exhibit 2 40 Busway Examples essere enne enne nee 2 39 Exhibit 2 41 Freeway HOV Lane Examples esee eee 2 39 Exhibit 2 42 Illustrative CBD Busway Capacities seseeeeee 2 41 Exhibit 2 43 Typical Busway Line Haul Passenger Volumes esses 2 42 Exhibit 2 44 Estimated Average Speeds of Buses Operating in Freeway HOV Lanes ta is iso tete tes tre oir we Ute tette 2 43 Exhibit 2 45 Type 1 Exclusive Bus Lane Examples sseeeeeee 2 45 Exhibit 2 46 Type 2 Exclusive Bus Lane Examples sese 2 46 Exhibit 2 47 Type 3 Exclusive Bus Lane Examples seseeeeee 2 46 Exhibit 2 48 Bus Stop Location Factors f eese nenne 2 48 Exhibit 2 49 Typical Values of Adjustment Factor f for Availability of Adjacent Lanes Wiper URS RE tente ena 2 49 Exhibit 2 50 Values of Adjustment Factor f for Type 2 Bus Lanes with Alternate Two Block Skip Stops e geret te pp
3. Bus lane vehicle capacity procedures vary depending on the facility type Chapters 3 5 present bus lane capacity procedures for busways and freeway HOV lanes exclusive arterial street bus lanes and mixed traffic situations Person Capacity Bus Stops The person capacity of a bus stop is related to the number of people boarding and alighting at the bus stop which influences the vehicle capacity of the bus stop Equation 2 6 shows this relationship P B P Equation 2 6 where P person capacity of a bus stop p h B vehicle capacity of the bus stop buses h from Equation 2 5 and Pis peak 15 minute passenger interchange per bus p bus Bus Routes and Bus Lanes The person capacity of a bus route or bus lane at its maximum load point under prevailing conditions is determined by the allowed passenger loading set by operator policy and by the number of buses operated during the analysis period typically one hour P Prax Snip PHF mlp max Equation 2 7 where Pap person capacity of a bus route or bus lane at its maximum load point under prevailing conditions p h Pu maximum allowed passenger loading per bus p bus Finto bus frequency on the route or the bus lane at its maximum load point buses h and PHF peak hour factor The person capacity of a bus route or bus lane in terms of number of boarding passengers during the analysis period may be considerably greater than the person capaci
4. Special phase Addition of a bus phase 1 Phase suppression Skipped non priority phases Preemption Unconditional Bus phase begins when all other intervals are Preemption Conditional Same as above except certain conditions are used _to determine when the bus phase should begin Occurs after bus detection Part 2 BUS TRANSIT CAPACITY Page 2 28 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Active priority should only be implemented at intersections operating at less than capacity so that the changes to signal timing that occur each time a bus passes through the intersection do not significantly worsen the intersection s level of service Automated systems that do not require bus driver intervention are preferable as bus drivers may not always remember to activate the system at the intersections equipped with signal priority equipment When coupled with two way data communication and automatic vehicle location AVL equipment on bus signal priority systems can be set to activate signal priority only when a bus is behind schedule Exhibit 2 26 illustrates one way that active signal priority can be implemented Streetside equipment can detect the bus for example using a transponder or bus mounted equipment can transmit a request for priority to the signal controller Exhibit 2 26 Bus Signal Priority Concept Bus approaches red signal SIGNA
5. Texas Transportation Institute Parsons Brinckerhoff Quade and Douglas Inc and Pacific Rim Resources Inc HOV Systems Manual NCHRP Report 414 Transportation Research Board Washington DC 1998 Part 2 BUS TRANSIT CAPACITY Page 2 70 Chapter 7 References Transit Capacity and Quality of Service Manual 8 EXAMPLE PROBLEMS Bus Dwell Time Calculation Number of Bus Berths Required at a Stop Bus Vehicle Capacity and Speed with an Exclusive Bus Lane Skip stop Operation Bus Vehicle Capacity in Mixed Traffic Near side Stops Bus Vehicle Capacity in Mixed traffic Far side stops Bus Vehicle Capacity in Mixed traffic Skip stop Operation Person Capacity Implementing an Exclusive Bus Lane on a CBD Street Implementing a Bus Queue Jump at a Traffic Signal CONOARWN Part 2 BUS TRANSIT CAPACITY Page 2 71 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Bus dwell time calculation Example Problem 1 The Situation An express route is planned along an arterial from a suburb to the CBD with 10 stops including one at a transit center midway stop 5 The route will operate in mixed traffic in the CBD stops 27 10 The Question What will be the average dwell times at the 10 stops and how might they affect how the route is developed The Facts Y The route will use 42 seat standard buses Y Exact fare is required upon boarding Y The door opening and closing time is 4 seconds Y A All
6. Buses Per Hour No Stops 8000 6000 4000 2000 I Peopl 0000 8000 6000 People per Lane per Hour 4000 2000 0 25 50 75 100 125 150 175 200 225 250 275 300 Buses Per Hour No Stops Part 2 BUS TRANSIT CAPACITY Page 2 2 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual TYPES OF BUS FACILITIES AND SERVICE The capacity procedures presented in Part 2 categorize bus service by the kinds of facilities that buses operate on and in the case of demand responsive service by the special operating characteristics that influence capacity These procedures will be presented in order from the most exclusive kinds of facilities used by buses to the least exclusive The most exclusive facilities and often the facilities where buses can achieve the highest speeds are busways and freeway high occupancy vehicle HOV lanes Busways are special roadways designed for exclusive use by buses A busway may be constructed at above or below grade and may be located either within a separate right of way or within a highway corridor Exhibit 2 2 depicts two examples of North American busways Buses share freeway HOV lanes with carpools and vanpools but are able to avoid congestion in the regular freeway lanes Exhibit 2 2 Busway Examples Ottawa Ontario Seattle Bus Tunnel Another form
7. for off line stops the additional re entry delay encountered when leaving a stop and reentering traffic The latter source of delay is incorporated into the clearance time used to calculate bus stop capacity The former is accounted for by the following capacity adjustment factor yop C Equation 2 18 where Tin mixed traffic adjustment factor ti bus stop location factor from Exhibit 2 48 v curb lane volume at a specific intersection and c curb lane capacity at a specific intersection The mixed traffic adjustment factor is essentially the same as the right turn adjustment factor presented in Equation 2 9 for exclusive arterial street bus lanes The difference is that in a mixed traffic situation the non transit traffic will be greater and it may not just be turning right it could also be going straight or even left and thus bus vehicle capacity will be lower in a mixed traffic situation than in an exclusive arterial street bus lane The most recent version of the Highway Capacity Manual should be used to determine the vehicle capacity of the curb lane Equation 2 19 may be used to calculate the bus vehicle capacity of a mixed traffic lane in which buses operate Page 2 60 Chapter 5 Mixed Traffic Transit Capacity and Quality of Service Manual B B 4N f Equation 2 19 where B mixed traffic bus capacity buses h By bus loading area capacity at the critical bus stop buses h Na number of eff
8. 240 240 140 14 0 15 0 15 0 Vehicle Capacity Loading area capacity bus h 42 42 65 65 100 100 95 95 Effective loading areas 2 45 2 60 2 45 2 60 245 2 60 2 45 2 60 Station capacity bus h 103 109 159 169 245 260 233 247 Passengers hour maximum load point Peak flow rate 15 min x 4 4 120 4 360 6 360 6 760 9 800 10 400 13 980 14 820 Average peak hour with PHF 2 760 2 920 4 260 4 530 6 570 6 970 9 370 9 930 Loading condition A Single door conventional bus simultaneous loading and unloading Loading condition B Two door conventional bus both doors loading or double stream doors simultaneously loading and unloading Loading condition C Four door conventional bus all double stream doors loading Loading condition D Six door articulated bus all doors loading NOTE Assumes 10 second clearance time 7 596 failure rate 6096 coefficient of variation 3 linear loading areas g C 1 0 PHF 0 67 50 of passengers board at heaviest CBD station 40 Seats per conventional bus 60 seats per articulated bus no standees allowed CALCULATING PERSON CAPACITY The theoretical person capacity of a busway or HOV lane at its maximum load point may be computed by multiplying the number of each type of vehicle per hour by the number of seats available per vehicle times a peak hour factor High speed bus service on busways and HOV lanes should not allow standees so capacity calculations should assume that every passen
9. Exhibit 2 27 Bus Queue Jump Concept Passengers board during red Exhibit 2 28 Bus Queue Jump Example Copenhagen Denmark Part 2 BUS TRANSIT CAPACITY Page 2 30 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Curb Extensions Where streets have curbside parking and high traffic volumes it may not be desirable for a bus to pull to the curb to stop because of the delays involved in waiting for a sufficiently large gap in traffic that will allow the bus to pull back into the travel lane In these situations the curb can be extended into the parking lane to allow buses to stop in the travel lane to pick up and discharge passengers The additional area curbside can be used to provide an ADA compliant clear area to load and unload wheelchair passengers to provide a bus shelter in a location that otherwise would not have enough space and to provide more room for passengers to stand while waiting for the bus Curb extensions can also create more on street parking as the area prior to the bus stop previously used by buses to pull to the curb can now be used for additional parking At intersections curb extensions also benefit all pedestrians by reducing the street width that must be crossed If bicycle lanes exist they may need to be routed around the curb extension creating potential bicycle pedestria
10. The number of buses in each platoon ideally should equal the number of loading areas provided at each stop used by the platoon of buses e Bus Stop Location As discussed in the bus stop section above far side stops allow for the highest bus lane capacity but other factors must also be considered when siting bus stops Person Capacity Person capacity is commonly calculated for three locations e bus stops e bus routes at the maximum load point and e bus lanes at the maximum load point As Exhibit 2 11 shows in addition to the factors discussed in the previous section relating to vehicle capacity there are other factors which must be considered when calculating person capacity Exhibit 2 11 Person Capacity Factors Operator Policy Allowed Passenger Loading Bus Frequency Peak Hour Factor Passenger Trip Lengths Passenger Demand Person Characteristics Capacity Boarding Volume Distribution Among Stops Loading Area Vehicle Capacity Bus Stop Vehicle Capacity Vehicle Capacity Bus Lane Vehicle Capacity Person capacity is commonly calculated for bus stops and for the maximum load point of a bus route or bus lane Part 2 BUS TRANSIT CAPACITY Page 2 13 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Increasing the maximum allowed passenger load increases person capacity but decreases quality of service Bus stop and
11. Transportation Planning Handbook Prentice Hall Inc Englewood Cliffs NJ 1992 6 Fitzpatrick Kay Kevin Hall Dennis Perkinson and Lewis Nowlin Guidelines for the Location and Design of Bus Stops TCRP Report 19 Transportation Research Board Washington DC 1996 7 Fritz Marshall S Effect of Crowding on Light Rail Passenger Boarding Times Transportation Research Record 908 Transportation Research Report Washington DC 1983 8 Guenthner R P and K C Sinha Modeling Bus Delays Due to Passenger Boardings and Alightings Transportation Research Record 915 Transportation Research Board Washington DC 1983 9 Highway Capacity Manual Special Report 209 Transportation Research Board Washington DC 1985 10 Highway Capacity Manual Special Report 209 Transportation Research Board Washington DC 1994 11 Hoel Lester A and Larry G Richards editors Planning and Development of Public Transportation Terminals Report DOT RSPA DPB 50 81 19 U S Department of Transportation Washington DC 1981 12 Hoey W F and H S Levinson Bus Capacity Analysis Transportation Research Record 546 Transportation Research Board Washington DC 1975 13 Homburger W S editor Transportation and Traffic Engineering Handbook Second Edition Prentice Hall Inc Englewood Cliffs NJ 1982 14 Interim Materials in Highway Capacity Transportation Research Circular 212 Transportation
12. both the bus lane volumes and the adjacent lane volumes play an important role in determining bus speeds e co a 0 80 Skip Stop Speed Adjustment Factor e e C o y N Cc o o e o o 0 55 0 50 Exhibit 2 54 Illustrative Skip Stop Speed Adjustment Effects Bus v c 0 0 Bus v c 0 1 Bus v c 0 2 Bus v c 0 3 Bus v c 0 4 Bus v c 0 5 Bus v c 0 6 Bus v c 0 7 Bus v c 0 8 Bus v c 0 9 Bus w e 1 0 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 0 Adjacent Lane v c Ratio NOTE Assumes two block skip stop pattern Part 2 BUS TRANSIT CAPACITY Page 2 56 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Bus Bus Interference Bus speeds within a bus lane along an arterial street decline as the lane becomes saturated with buses This is because as the number of buses using the lane increases there is a greater probability that one bus will delay another bus either by using available loading areas or by requiring passing and weaving maneuvers Simulation runs reported in TCRP Report 26 77 as well as observations of actual bus lane operations show a sharp drop in bus speeds as bus volumes approach capacity Exhibit 2 55 presents the speed adjustment factor for bus volumes These factors were developed through simulation
13. e many to many e many to few e few to many e few to few and e many to one Many to many occurs when the provider places no constraints on the type of trips it handles In other words the origins and destinations are random and can occur anywhere Many to few occurs when the provider has only a couple of popular destinations hospitals shopping areas and the like and random origins Few to many occurs when the reverse happens Few to few serves a limited number of origins and destinations Finally many to one occurs when there is only one destination such as a senior center and random origins Exhibit 2 62 shows these five scenarios graphically Exhibit 2 62 Demand Responsive Transit Service Patterns Many to Many Many to Few A Origins E Destinations Potential Trips Many to One Few to Few Few to Many Deviated Fixed Route Transit A variation of fixed route service that incorporates elements of demand responsive service is deviated fixed route transit This form of service is often used to expand the potential service area of a single route in a low density area by allowing deviations up to a set distance from the usual route to pick up and drop off passengers It is also sometimes used by transit systems as a way of meeting Americans with Disabilities Act ADA requirements for providing complimentary paratransit service within the service area of a fixed route bus line In this latter situation the fixed rout
14. 0 50 1 00 0 50 0 50 1 00 0 50 1 00 0 50 1 00 30 4 63 79 117 105 154 113 167 UI 170 60 26 36 48 67 64 89 69 96 70 98 90 19 25 35 47 46 62 49 67 50 69 120 15 20 27 36 36 48 39 52 39 53 NOTE Assumes 15 second clearance time 2596 queue probability and 6095 coefficient of variation of dwell times To obtain the vehicle capacity of non linear on line bus stops multiply the one loading area values by the number of loading areas provided Exhibit 2 19 provides a further guide for estimating on line linear bus stop capacity It shows the number of buses per hour for selected dwell times and g C ratios based on a 15 second clearance time Increasing the number of linear loading areas has a much smaller effect on changes in capacity than reducing dwell times Note that for dwell times greater than 60 seconds the differences between a g C of 0 5 and 1 0 are small Exhibit 2 19 Bus Stop Maximum Vehicle Capacity Related to Dwell Times and Number of Loading Areas 30 s dwell g C 1 0 30 s dwell g C 0 5 60 s dwell g C 1 0 60 s dwell g C 0 5 120 s dwell g C 1 0 RES 120 s dwell g C 0 5 Vehicle Capacity bus h 2 3 4 Number of Linear On Line Loading Areas Part 2 BUS TRANSIT CAPACITY Page 2 21 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Bus Lanes
15. 12 ft travel lanes arterial class IV Y Far side on line stops located every two blocks with a two block skip stop operation in use Y Noright turns will be allowed across the bus lane Y Buses will be able to use the adjacent mixed traffic lane to pass other buses in the exclusive bus lane i e the lane will be a Type 2 exclusive bus lane Y Blocks are 135 m 440 ft long with signalized intersections at the end of each block Y 10 buses per hour will be express buses with no standees allowed by policy the remaining buses will be local buses on which standees will be allowed The buses in use have 43 seats Y Average vehicle occupancies are 1 2 for automobiles 40 for express buses and 50 for local buses Y Busesarrive randomly Half of the buses will use A pattern skip stops the other half will use B pattern skip stops in the alternate blocks The critical B pattern stop has the same characteristics as the critical A pattern stop Y Under the exclusive bus lane scenario the automobiles currently making right turns from this street will have to divert to a parallel street to make their turns incurring an extra 60 seconds of delay each Added delay to vehicles on these parallel streets as well as the reduced delay to other vehicles that take their place on the bus street is neglected Comments Y The base saturation flow rate vo is 1900 pv hg In Y Traffic volumes in the left two lanes are assumed to be evenly dis
16. 2 13 5 11 7 6 11 5 8 3 10 3 10 5 9 2 8 9 0 6 9 8 3 8 4 7 6 10 6 9 5 6 6 5 6 5 6 1 30 second dwell time 2 19 5 11 8 16 3 168 14 0 4 13 0 10 7 11 5 11 8 10 3 6 9 7 7 3 8 8 9 0 8 0 8 7 5 6 0 7 0 7 0 6 5 10 5 8 4 9 5 5 5 5 5 2 f 40 second dwell time 2 17 6 11 1 15 0 15 4 13 0 4 11 4 8 3 10 2 10 4 9 3 6 8 3 6 5 7 7 7 8 7 1 8 6 4 5 3 6 0 6 1 5 7 L 10 5 0 43 4 8 4 8 4 5 i 50 second dwell time 2 16 0 10 5 13 8 142 12 1 4 10 1 7 6 9 2 9 3 8 4 6 7 3 5 9 6 8 6 9 6 3 8 5 6 4 7 5 3 5 4 5 1 10 4 4 3 8 4 2 4 2 4 0 i i 60 second dwell time 2 14 7 9 9 12 8 13 1 11 4 4 9 1 7 0 8 4 8 5 7 7 6 6 5 5 4 6 1 6 2 5 7 8 5 0 4 3 4 8 4 8 4 5 10 3 9 3 5 3 8 3 8 3 6 NOTE Data based on field measurements Traffic delays shown reflect peak conditions Dwell times are average dwell times a Without traffic or control delays Includes signal and right turn delays Includes control delay This column should also be used for single normal flow bus lanes where the capacity analysis includes deductions for right turn interferences Part 2 BUS TRANSIT CAPACITY FINAL DRAFT Page 2 94 Appendix B Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 2 60a Estimated Bus Speeds V mph Mixed Traffic CBD Central City Suburbs Stops Delay Delay Delay mi 3 0 min mi 0 9 min mi 0 7 min mi 10 second dwell
17. 200 400 Wherever vehicular turn provisions prohibitions are located along routes Busways and Freeway HOV Lanes In North America busways and reserved lanes on freeways are mainly found in larger cities usually with a large downtown employment and heavy peak hour bus ridership However busways have found wide application internationally as a substitute for or supplement to rail systems Brazil Curitiba and Sao Paulo has pioneered efficient busways with high level pre paid stations as shown in Exhibit 2 34 Dwell times are similar to rail transit resulting in higher average speeds and higher vehicle utilization Bi articulated buses capable of carrying up to 270 passengers are operated on the city s five express busways Larger terminals located at the termini of the busways and smaller terminals located approximately every 2 km 1 2 mi along the busways provide transfer opportunities to inter district and local feeder buses These terminals are also pre paid areas so passengers do not have to pay a separate fare or show a fare receipt when transferring between buses similar to a transfer station on a rail transit system Curitiba s distinctive high level tube stations are equipped with wheelchair lifts allowing passengers in wheelchairs to roll directly onto the bus when it arrives Passengers pay an attendant at the tube station when they enter so that no fares need be collected on board the bus 9 P
18. 225 4 300 5 975 6 450 Peak hour factor These person flow rates indicate the number of people that can be carried assuming uniform flow during the peak hour Appropriate peak hour factors should be used to discount these values to reflect flow variations within the 15 minute peak period Part 2 BUS TRANSIT CAPACITY Page 2 24 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual 2 OPERATING ISSUES INTRODUCTION This chapter presents operating issues that influence the results of the capacity procedures presented in the remainder of Part 2 Factors under the direct control of bus operators are the allowed passenger loads on a bus and whether or not a skip stop pattern is used on streets with high bus volumes Bus preferential treatments at intersections and on roadway segments in order to be implemented require the cooperation of bus operators and the agencies responsible for streets and roads BUS OPERATIONS Passenger Loads From a capacity perspective the allowed passenger load on a bus set by policy constrains the number of people that a given number of buses can carry From a passenger s perspective loading reflects the comfort level of the on board portion of a bus trip both in terms of being able to find a seat and in overall crowding levels within the bus From a transit operator s perspective liability concerns and the desire to provide every customer with a seat for high speed or lo
19. 250 300 350 400 Right Turning Volume veh h 100 peds 60 s dwell 400 peds 60 s dwell 800 peds 60 s dwell ae 100 peds 30 s dwell 400 peds 30 s dwell 800 peds 30 s dwell NOTE Assumes 15 second clearance time 2596 queue probability 6096 coefficient of variation of dwell times permitted right turn signal phasing shared right turn lane and bus volumes minimal in relation to right turn volumes Par 1 0 Part 2 BUS TRANSIT CAPACITY Page 2 51 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Saturation flow adjustment factor for bus use of an adjacent lane Bus Effects on Passenger Vehicle Capacity in an Adjacent Lane The introduction of single or dual bus lanes reduces a roadway s vehicle capacity for other traffic The extent of this reduction is determined by 1 the bus lane type 2 the number of buses using the bus lane and 3 whether or not the bus lane replaces a curb parking lane The following impacts are associated with the provision of a single or dual bus R29 lane e Ifthe lane is already used primarily by buses the vehicle capacity loss will be relatively small However when the lane is introduced for relatively low existing bus flows i e fewer than 40 buses per hour the reduction in vehicle capacity could be as much as 30 50 of one travel lane e Introducing a single dedicated curb lane for buses onto a street with no previous b
20. 40 43 1 50 0 75 person capacity at its maximum load P 2 250people point i peop The Results Under the proposed operation the street can carry about 1 770 people per hour in buses at its maximum load point If the street s bus vehicle capacity of 50 buses per hour were to be scheduled the street s person capacity would be about 2 250 people at the maximum load point Part 2 BUS TRANSIT CAPACITY Page 2 83 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Implementing an exclusive bus lane on a CBD street Example Problem 8 The Situation A transit operator currently operates 40 buses in mixed traffic on a three lane one way CBD street Example Problems 4 6 The transit operator would like to accommodate future growth in bus volumes and to maintain schedules as city streets become more congested and therefore has proposed that one lane of the street be converted to exclusive bus use with right turns prohibited from the lane The city traffic engineer is concerned about the additional delay that will be experienced by motorists if the lane is implemented The Question Will the proposed exclusive bus lane increase or decrease overall person delay The Facts Y Same assumptions as Example Problem 6 Y Pre timed signals 60 second cycle g C 0 45 arrival type 5 40 km h 25 mph free flow speed Y 1200 automobiles and 40 buses per hour use the street Y No on street parking no grades 3 6 m
21. 7 15 6 11 7 14 2 14 5 12 9 5 0 12 1 9 7 11 3 11 3 10 5 62 9 3 7 9 8 9 8 9 8 4 i 40 second dwell time 1 2 28 3 17 9 24 1 24 8 20 9 2 5 18 3 13 4 16 4 16 7 15 0 3 7 13 4 10 5 12 4 12 6 11 4 5 0 10 3 8 5 9 7 9 8 9 2 62 8 0 69 7 7 7 7 7 2 50 second dwell time 12 25 7 16 9 22 2 229 19 5 2 5 16 3 12 2 14 8 15 0 13 5 3 7 11 7 9 5 10 9 11 1 10 1 5 0 9 0 7 6 8 5 8 7 8 2 6 2 7 1 6 1 6 8 6 8 6 4 i 60 second dwell time 1 2 23 7 15 9 20 6 21 1 28 3 2 5 14 6 11 3 13 5 13 7 12 4 3 7 10 5 8 7 9 8 10 0 9 2 5 0 8 0 6 9 7 7 7 7 7 2 6 6 3 5 6 6 1 6 1 5 8 NOTE Data based on field measurements Traffic delays shown reflect peak conditions Dwell times are average dwell times Without traffic or control delays b E Includes signal and right turn delays Includes control delay This column should also be used for single normal flow bus lanes where the capacity analysis includes deductions for right turn interferences For alternating skip stop patterns the ability of buses to leave the curb bus lane to pass stopped buses becomes a factor in the ability to attain the two or three fold increase in speed This ability depends on the availability of the adjacent lane or the provision of an off line bus stop Where dual bus lanes or off line bus stops are provided the anticipated bus speed can be calculated using the distance between the bus stops served Where congestion in the adjacent lane results in essentia
22. Cherry Downtown Space for Buses The Manhattan Experience Transportation Research Record 1308 Transportation Research Board Washington DC 1991 Levinson Herbert S and Kevin R St Jacques Bus Lane Capacity Revisited Preprint 100 presented at the Transportation Research Board 1998 Annual Meeting Major Michael J Brazil s Busways A Subway That Runs Above the Ground Mass Transit Vol XXIIL No 3 May June 1997 Marshall Leo F Herbert S Levinson Lawrence C Lennon and Jerry Cheng Bus Service Times and Capacities in Manhattan Transportation Research Record 1266 Transportation Research Board Washington DC 1990 Papacostas C S Capacity Characteristics of Downtown Bus Streets Transportation Quarterly Vol 36 No 4 pp 617 630 October 1982 Pushkarev B S J M Zupan and R Cumella Urban Rail in America A Regional Plan Association Book Indiana University Press Bloomington IN 1982 Rabinovitch Jonas and Josef Leitman Urban Planning in Curitiba Scientific American Vol 274 No 3 March 1996 St Jacques Kevin and Herbert S Levinson Operational Analysis of Bus Lanes on Arterials TCRP Report 26 Transportation Research Board Washington DC 1997 Scheel W and J E Foote Bus Operation in Single Lane Platoons and Their Ventilation Needs for Operation in Tunnels Research Publication GMR 8068 General Motors Research Laboratories Warren MI 1962
23. Research Board Washington DC 1980 15 King Rolland D New Designs and Operating Experiences with Low Floor Buses TCRP Report 41 Transportation Research Board Washington DC 1998 16 Kohler V Capacity of Transit Lanes Proceedings of the International Symposium on Highway Capacity Karlsruhe Germany 1991 17 Kraft W H An Analysis of the Passenger Vehicle Interface of Street Transit Systems with Applications to Design Optimization Doctoral Dissertation New Jersey Institute of Technology Newark NJ 1975 Part 2 BUS TRANSIT CAPACITY Page 2 69 Chapter 7 References Transit Capacity and Quality of Service Manual 8 20 21 22 23 24 25 26 27 28 29 30 31 Kraft W H and P Eng Wong Passenger Service Time Characteristics of Street Transit Systems Compendium of Technical Papers Institute of Transportation Engineers 47 Annual Meeting Mexico City Mexico 1977 Levinson H S Analyzing Transit Travel Time Performance Transportation Research Record 915 Transportation Research Board Washington DC 1983 Levinson H S INET Transit Travel Times Analysis prepared for the Urban Mass Transit Administration Washington DC April 1982 Levinson H S C L Adams and W F Hoey Bus Use of Highways Planning and Design Guidelines NCHRP Report 155 Transportation Research Board Washington DC 1975 Levinson H S L Lennon and J
24. Six channels off line stops NOTE PHF 0 67 Six channel configurations assume 60 passenger articulated buses CALCULATING SPEED The average speed of a bus operating on a busway or freeway HOV lane depends on three factors 1 the running speed of the bus in the lane 2 bus stop spacing and 3 dwell time at bus stops The Highway Capacity Manual may be used to estimate the running speed of a bus in a busway or freeway HOV lane given the free flow speed of the lane the traffic volume in the lane and the mix of passenger vehicles and buses using the lane Note that this estimated speed assumes that the lane is operating below capacity The time required to travel through a given length of busway or HOV lane without stopping can be calculated from this running speed Bus stop spacing affects the number of times a bus must dwell as well as the number of times the bus experiences added delay due to deceleration and acceleration into and out of stops A rate of 1 2 m s 4 0 ft s may be assumed for an acceleration and deceleration rate in the absence of local data Exhibit 2 44 presents average travel speeds for a selection of running speeds dwell times and bus stop spacings As would be expected average bus speeds decrease as the stop spacing increases or as the average dwell time per stop increases Part 2 BUS TRANSIT CAPACITY Page 2 42 Chapter 3 Busways and Freeway HOV Lanes Exhibit 2 44 Estimated Average Spe
25. available however this lowers the passengers quality of service The upper ends of the total capacity ranges represent crush capacity and should not be used for transit capacity calculations A typical 12 meter 40 foot urban transit bus can normally seat 43 passengers and can carry up to 37 additional standees if all of the aisle circulation space is filled Similarly an 18 meter 60 foot articulated bus can carry 65 seated passengers and 55 standees However bus operator policy often limits the number of standees to levels below this theoretically offered or crush capacity Part 2 BUS TRANSIT CAPACITY Page 2 25 Load factor An alternative table using U S customary units appears in Appendix B Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Maximum schedule loads Crush loads Minimum passenger space requirements Capacity adjustment for the availability of the adjacent lane Maximum schedule load is synonymous with capacity assuming a reasonable number of standees It represents the upper limit for scheduling purposes Maximum scheduled loads are typically 125 to 150 percent of a bus seating capacity e g 54 64 passengers on a typical 12 meter or 40 foot bus Crush loads typically loads above 150 percent of a bus seating capacity subject standees and other passengers to unreasonable discomfort Such loads are unacceptable to passengers Crush loads prevent circulation of
26. be carefully considered Requires on going enforcement Part 2 BUS TRANSIT CAPACITY Page 2 38 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual 3 BUSWAYS AND FREEWAY HOV LANES INTRODUCTION This chapter presents methodologies for analyzing the operation of buses using Busways are characterized by at busways and freeway HOV lanes Busways are characterized by 1 uninterrupted flow HIER a ia aes 2 exclusive use by buses and 3 lanes separated from other traffic Some facilities uninterrupted flow called busways such as the South Miami Busway have interrupted traffic flow due to traffic signals and should be treated as exclusive arterial street bus lanes Bus stops if Bus facilities with interrupted d any along the facility are either located off line or a passing lane is provided at the stop n AER Exhibit 2 40 presents examples of North American busways High occupancy vehicle addressed in Chapter 4 HOV lanes are not necessarily separated from other traffic and may allow passenger vehicles with a designated number of occupants typically 2 or 3 to use the lanes See examples in Exhibit 2 41 Exhibit 2 40 Busway Examples Ottawa Pittsburgh Seattle Bus Tunnel Dallas Southwestern Medical Center Exhibit 2 41 Freeway HOV Lane Examples Shirley Highway Virginia New Jersey Lincoln Tunnel approach Part 2 BUS TRANSIT CAPACITY Page 2 39 Chapter 3 Busways and Fr
27. boarding and alighting times at each stop plus the 4 s door opening and closing time The Results Estimated dwell times are shown below for each stop Stop 1 2 23 4 5 6 7 8 9 10 l Dwell Time s 64 52 37 _46 60 32 36 42 34 2 Boarding times govern at stops 1 7 while alighting times govern at stops 28 10 Stop 8 is the critical bus stop for this route within the CBD area Because of the long dwell times at stops 1 4 in the suburban portion of the corridor off line stops pullouts should be Part 2 BUS TRANSIT CAPACITY Page 2 72 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual considered at these locations to avoid substantial traffic delays to other vehicles in the curb lane At the same time to minimize delays to the express buses when re entering the arterial transit priority treatments such as queue jumps should also be considered at these locations The dwell time at stop 5 required to serve passenger movements is 60 seconds However since this stop is located at a transfer center buses will likely need to occupy the berth for longer periods of time to allow for connections between routes This extra berth occupancy time needs to be accounted for when sizing the transfer center Having standees on board a long distance express bus is not desirable from a quality of service point of view Increasing service frequency so that all riders may have a seat should also be considered P
28. bus lane person capacities are constrained by the maximum vehicle capacities of those locations Bus route person capacity is usually constrained by the service frequency set by the transit operator Operator Policy Two factors directly under the control of the bus operator are the maximum passenger load allowed on buses and the service frequency An operator whose policy requires all passengers to be seated will have a lower potential passenger capacity for a given number of buses than one whose policy allows standees The quality of service experienced by passengers though will be higher with the first operator The bus frequency determines how many passengers can actually be carried even though a bus stop or lane may be physically capable of serving more buses than are actually scheduled Passenger Demand Characteristics How passenger demand is distributed spatially along a route and how it is distributed over time during the analysis period affects the number of boarding passengers that can be carried The spatial aspect of passenger demand in particular is why passenger capacity must be stated for a given location not for a route or a street as a whole During the period of an hour passenger demand will fluctuate The peak hour factor reflects passenger demand volumes over typically a 15 minute period during the hour A bus system should be designed to provide sufficient capacity to accommodate this peak passenger demand H
29. capacity using a freeway lane as an example The number of buses operated is set by the service provider The number of cars that can operate in the lane used by buses reflects the passenger vehicle capacity of the freeway lane after deducting the vehicle equivalencies of the buses The total person capacity thus represents the number of people that can be carried by the specified number of buses and the remaining passenger vehicles For the purposes of this example the capacity of the freeway lanes are assumed to be 2 300 passenger vehicles per hour per lane without buses one bus is assumed to be the equivalent of 2 passenger vehicles buses are assumed not to stop along the freeway and buses and passenger vehicles are assumed to have average occupancies of 47 and 1 3 respectively corresponding to typical major city vehicle occupancies It can be seen that as the number of buses using a freeway lane increases to 300 the person capacity of that lane increases from about 3 000 to over 16 800 while the vehicle capacity drops only from 2 300 to 2 000 1 700 passenger vehicles plus 300 buses Note that this figure only refers to capacity not to demand or actual use Exhibit 2 1 Examples of Freeway Vehicle and Person Capacity 2500 T T Total Vehicles i 2250 J 2000 1750 1500 Cars 1250 1000 Vehicles Per Lane Per Hour 750 500 250 mem 0 0 25 50 75 100 125 150 175 200 225 250 275 300
30. determining the vehicle capacity is stop 1 The curb lane bus vehicle capacity is 15 buses per hour which is insufficient to accommodate the proposed number of buses The simplest way if space permits to add capacity to a one or two berth bus stop is to add another berth However in this case the transit operator desires to minimize pedestrian walking distances by limiting the number of loading areas to two Another option is to increase the failure rate that is allowed however this decreases schedule and headway reliability and should be avoided when possible Therefore the analyst will need to evaluate other potential solutions These solutions are the subject of subsequent example problems Part 2 BUS TRANSIT CAPACITY Page 2 79 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Mixed traffic lane bus vehicle The Situation capacity with far side stops The Question The Facts Example Problem 5 The CBD street from Example Problem 4 Having determined that a mixed traffic lane with near side stops will not work the transit operator would like to try far side stops to avoid some of the right turn interferences How will the street operate under this scenario Same assumptions as Example Problem 4 except that stops are now far side Outline of Solution As in Example Problem 4 all input parameters are known and the critical bus stop will determine the bus lane capacity The only factor tha
31. dwell time but as intersection delay time Exhibit 2 65 Sample Dwell Time Data Collection Sheet Dwell Time Data Sheet Date Time Bus No Bus Type Route Run No Direction Stop Arrival Doors Main Doors Bus Passengers Passengers Psgrs Notes Name Time Open Flow Closed Leaves Boarding Alighting Departing Stops Front Rear Front Front Rear OnBoard _ Board BESS EE IER es a a Part 2 BUS TRANSIT CAPACITY Page 2 91 Appendix A Dwell Time Data Collection Procedure Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 92 Appendix A Dwell Time Data Collection Procedure Transit Capacity and Quality of Service Manual APPENDIX B EXHIBITS IN U S CUSTOMARY UNITS Exhibit 2 23a Characteristics of Bus Transit Vehicles United States and Canada f l aaa Length Width Typical Capacity Bus Type f f Seats Standees Tota Small Bus Minibus 18 30 6 5 8 0 3830 010 840 mt Bus 35 8 0 8 5 30 35 20 30 50 60 40 8 5 35 50 30 40 65 75 l low floor 40 8 0 30 40 25 40 55 70 articulated 60 8 0 8 5 65 55 120 NOTE In any transit vehicle the total passenger capacity can be increased by removing seats and by making more standing room available however this lowers the passengers quality o
32. exclusive bus lane vehicle capacity that cover a comprehensive range of situations However it is possible to illustrate the magnitude of the influence of certain factors on bus lane vehicle capacity Exhibit 2 51 illustrates the effects of dwell time right turning volume from the bus lane and conflicting pedestrian volumes on bus lane vehicle capacity It assumes 20 buses scheduled per hour that all use the same stop conflicting pedestrian volumes ranging from 100 800 per hour dwell times of 30 60 seconds and right turning volumes of 0 400 vehicles as well as various other assumptions held constant that are listed in the exhibit It can be seen that as dwell time decreases bus vehicle capacity increases Conflicting pedestrian volumes under 200 per hour have little effect on bus vehicle capacity but have substantial effects at higher conflicting volumes especially as right turning volumes increase However when right turn conflicts do not exist conflicting pedestrian volumes have no impact on vehicle capacity and the lines for a given dwell time converge to a single point It can also be seen that the lines for a given pedestrian volume converge towards a point where the right turn capacity is exceeded and the bus lane vehicle capacity drops to zero Between these two extremes bus vehicle capacity steadily declines as right turning volumes increase until a point is reached where the bus demand volumes exceed the bus lane vehicle capacit
33. expressed in this equation the number of buses in the adjacent lane would be half the total bus flow when an alternating two block skip stop operation approaches capacity Two thirds of the buses would use the adjacent lane for a three block pattern However these impacts would not take full effect until the bus volumes approached capacity CALCULATING PERSON CAPACITY The person capacity at the maximum load point of an arterial street bus lane can be determined by multiplying the bus lane vehicle capacity given by Equation 2 12 or Equation 2 13 as appropriate by the allowed passenger loading on board an individual bus times a peak hour factor CALCULATING SPEED The best way to determine bus travel speeds is to measure them directly When this is not possible for example when planning future service speeds can be estimated by 1 driving the route making an average number of stops with simulated dwells making two or three runs during peak and off peak times 2 scheduling buses based on similar routes and adjusting running times as needed based on the operating experience or 3 using the analytical method described below to estimate speeds Bus speeds on an exclusive arterial street bus lane are influenced by bus stop spacing dwell times delays due to traffic signals and right turning traffic skip stop operations and interferences between buses operating in the lane These factors are reflected in Equation 2 16 A base bus speed i
34. get o DR UNTER PEU IDE EORR 2 49 Exhibit 2 51 Illustrative Exclusive Bus Lane Vehicle Capacity Non Skip Stop Operation blinds testi sah Sees de Sore teeta al St ay Seed die SiS MI dd Ae teat oa MIL e cite 2 51 Exhibit 2 52 Illustrative Exclusive Bus Lane Vehicle Capacity Skip Stop Operation 2 51 Exhibit 2 53 Estimated Arterial Street Bus Speeds Vo km h 0 eee eeeeceereeeneeeeenees 2 55 Exhibit 2 54 Illustrative Skip Stop Speed Adjustment Effects sssss 2 56 Exhibit 2 55 Bus Bus Interference Factor fp essere 2 57 Exhibit 2 56 Illustrative Bus Bus Interference Factor Effects ssss 2 57 Exhibit 2 57 Type 1 Mixed Traffic Bus Lane Portland OR sess 2 59 Exhibit 2 58 Type 2 Mixed Traffic Bus Lane Vancouver BC sss 2 60 Exhibit 2 59 Illustrative Mixed Traffic Maximum Bus Vehicle Capacity 2 61 Exhibit 2 60 Estimated Bus Speeds V km h Mixed Traffic uses 2 63 Exhibit 2 61 Characteristics of Different Demand Responsive Bus Systems 2 65 Exhibit 2 62 Demand Responsive Transit Service Patterns esssess 2 66 Exhibit 2 63 Deviated Fixed Route Service Patterns esessseeeee 2 67 Exhibit 2 64 Sample Passenger Service Time Data Collection Sheet 2 90 Exhibit 2 65 Sample Dwell Time Data Collection Sheet
35. loading areas provided and their design The vehicle capacity of loading areas was discussed in the previous section The factors that determine how many loading areas need to be provided at a given bus stop were shown in Exhibit 2 7 and are examined in more detail below Advantages and disadvantages of near side far side and mid block Stops Part 2 BUS TRANSIT CAPACITY Page 2 11 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Bus Stop Loading Area Requirements The key factors influencing the number of loading areas that are required at a bus stop are the following Failure rate Linear loading areas are less efficient than other loading area designs Bus Volumes The number of buses that are scheduled to use a bus stop during an hour directly affects the number of buses that may need to use the stop at a given time If insufficient loading areas are available buses will queue behind the stop decreasing its vehicle capacity In this situation passenger travel times will increase and the on time reliability experienced by passengers will decrease both of which negatively affect quality of service Probability of Queue Formation The probability that queues of buses will form at a bus stop known as the failure rate is a design factor that should be considered when sizing a bus stop Loading Area Design Loading area designs other than linear sawtooth drive through etc are 10096 effec
36. of Type 1 and Type 2 bus lanes using an 80 second cycle a g C ratio of 0 5 125 meter 400 foot block spacing 20 to 50 second dwell times and a 33 percent coefficient of dwell time variation Exhibit 2 55 Bus Bus Interference Factor p Bus Lane v c Ratio Bus Bus Interference Factor lt 0 5 1 00 0 5 0 97 0 6 0 94 0 7 0 89 0 8 0 81 0 9 0 69 1 0 0 52 1 1 0 35 Exhibit 2 56 illustrates the effects of increasing bus lane volumes on bus speeds There is little effect on bus speeds until approximately 70 of the bus lane s capacity is being used Exhibit 2 56 Illustrative Bus Bus Interference Factor Effects 30 25 Nm eo Bus Speed km h a 10 5 PM 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 14 Bus Lane Volume Capacity Ratio 1 2 stops km 2 stops mi 2 5 stops km 4 stops mi 3 7 stops km 6 stops mi 5 0 stops km 8 stops mi 6 2 stops km 10 stops mi NOTE Assumes suburban conditions 30 second dwell times and a single normal flow bus lane Speed adjustment factor for bus volumes fp Part 2 BUS TRANSIT CAPACITY Page 2 57 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 58 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality o
37. of bus facility is exclusive arterial street bus lanes typically found along downtown streets These lanes are reserved primarily for buses either all day or during specified periods Depending on local regulations they may be used by other traffic under certain circumstances such as by vehicles making turns or by taxis motorcycles carpools or other vehicles that meet certain requirements Exhibit 2 3 shows an example of an arterial street bus lane the downtown Portland Oregon bus mall Exhibit 2 3 Exclusive Arterial Street Bus Lane Example Portland OR Ottawa Ontario has North America s most extensive busway system with five busways totaling 32 2 km 19 3 mi The five station 2 1 km 1 3 mi downtown Seattle bus tunnel serves dual powered electric and diesel trolleybuses and was designed to accommodate future light rail Part 2 BUS TRANSIT CAPACITY Page 2 3 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual The most common operating environment for buses is in mixed traffic where buses share roadways with other traffic In this environment capacity procedures must account for the interactions between buses and other traffic and whether or not buses stop in the traffic lanes on line stops or out of the traffic lanes off line stops Exhibit 2 4 illustrates a typical mixed traffic condition Exhibit 2 4 Mixed Traffic Example Portland OR The final category of bus service is de
38. passengers board through the front door and alight through the back door Y The transit agency has estimated potential ridership for the route and predicts the following average number of boarding and alighting passengers per stop Stops 1 2 3 4 5 6 7 8 9 10 Alighting Passengers 0 0 3 2 4 6 6 9 415 Boarding Passengers 20 16 11 12 16 8 2 1 0 0 Comments Y Assume 3 0 seconds boarding time per passenger 3 5 seconds with standees Y Assume 2 0 seconds alighting time per passenger Outline of Solution All input parameters are known Method 3 calculation will be used to determine dwell times As there are two doors one used by boarding passengers and the other by alighting passengers boarding and alighting times will need to be calculated separately for each stop to determine which governs dwell time The total number of passengers on board the bus will need to be tracked to determine the stops where standees will be present on the bus Steps 1 Determine the stops where the There will be more than 42 passengers on the bus arrives with standees bus when it arrives at stops 3 7 2 Calculate the boarding time The boarding time is the number of boarding passengers times 3 0 or 3 5 seconds depending on whether or not standees are present 3 Calculate the alighting time The alighting time is the number of alighting passengers times 2 0 seconds 4 Determine the dwell time The dwell time is the larger of the
39. procedure involves identifying the base bus speed in mixed traffic from Exhibit 2 53 and modifying this speed by adjustment factors for skip stop operation and bus bus interferences Steps 1 Calculate the capacity of the adjacent y IC lane using the procedures given in o 8 CM fa fa Chapter 16 of the Highway Capacity c 1900 veh h 0 45 0 98 0 90 Manual c 754 veh h 2 Calculate the adjacent lane 3 impedance factor from Equation 2 a 1 0 d gt 11 e 3 a 1 0 8 200 754 a 0 77 Part 2 BUS TRANSIT CAPACITY Page 2 75 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Part 2 BUS TRANSIT CAPACITY Calculate the skip stop adjustment factor from Equation 2 10 Arrivals are random therefore the K factor is 0 50 The bus lane vehicle capacity is given by Equation 2 13 and is equal to the sum of the two pattern s critical bus stop vehicle capacities times the factor calculated in Step 3 Because both patterns have the same dwell times and right turns are prohibited their critical bus stop vehicle capacities are the same 35 bus h from Example Problem 2 Bus speeds under the all stop scenario can be calculated from Equation 2 16 The skip stop speed adjustment factor fs is 1 0 for this scenario since skip stops are not used The bus bus interference factor f is determined from Exhibit 2 55 vic 38 65 0 58 and by interpolation f is 0 95 This assumes that all
40. route hail specialized high I request Areawide Semi regular Many to many 6 15 Riders not well City Moderate to route hail served by high lI request _other transit Commuter Pre Few to one 10 15 Commuters State Low Vans arranged I scheduled L L L L I Employer and Developer Sponsored Services _ E Shuttles Pre Fixed route loop 15 30 Commuters Local State Low arranged often one to students regular route one Vanpools Pre Many to one 6 15 Commuters State Low arranged scheduled Buspools Pre Few to one 30 60 Commuters State Low arranged scheduled L L L L Vehicle Types There are a wide variety of vehicles available for demand responsive services These vehicles are usually not the articulated or standard buses typically used for fixed route service Typically demand responsive vehicles are smaller because of the greater variety of roadways upon which they must operate and the smaller passenger loads that can be served within an acceptable travel time The following is a list of the kinds of vehicles that are used in demand responsive service e private automobiles e taxi cabs e jitney vans and buses R2 e commercial vans and buses and e paratransit vans and buses Part 2 BUS TRANSIT CAPACITY Page 2 65 Chapter 6 Demand Responsive Transit Capacity and Quality of Service Manual Operating Scenarios The following operating scenarios exist for demand responsive transit
41. seta tune ta senten sts tasses tuse ta sensns estu aeneus 2 59 IntrOdUCctoh Meee seen reo RR Ue ene et eR Aid 2 59 Bus Lane Types iiss tesa ehe eta vee ahs eite itid 2 59 Calculating Vehicle Capacity seeeeeeeeeseeeeee eene nennen nennen rennen 2 60 Calculating Person Capacity te opere ptm tem petere 2 61 Calculating Speed ui eei eo ene dedere diea eie ee ce ee 2 62 6 DEMAND RESPONSIVE eeeee eese enne tn enata snas tatu sins tatu sins tatu sons ta sus on statuo 2 65 Iu 2 65 Vehicle Types ieu ae HE PR BE RUE UC e e pen 2 65 Operating Scenarios i iecit eerie leceabeese haere te resi eive ac Deka dnb gin 2 66 Deviated Fixed Route Transit eese 2 66 Calculating Vehicle Capacity ente tree ene reo IE EEEE ss teneri 2 67 Mono 2 69 8 EXAMPLE PROBLEMSS eese esee eee dan Sra EA KFE AINEEN 2 71 APPENDIX A DWELL TIME DATA COLLECTION PROCEDURE 2 89 Hrs 2 89 Passenger Service Times eee desee e EEEE E eE EERE EE euren 2 89 Dwell Times ote koa eine gina ies gin mere eee 2 90 APPENDIX B EXHIBITS IN U S CUSTOMARY UNITS eere 2 93 LIST OF EXHIBITS Exhibit 2 1 Examples of Freeway Vehicle and Person Capacity ssss 2 2 Exhibit 2 2 Busway Examples etie eere etos eee ii ecd dn 2 3 Exhibit 2
42. street using Equation 2 13 The Results If skip stops are implemented and bus stops are placed on the far sides of intersections there will be sufficient capacity for the proposed 40 buses per hour with some excess capacity to accommodate more buses in the future Part 2 BUS TRANSIT CAPACITY Page 2 82 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Example Problem 7 The Situation The CBD street from Example Problems 4 6 Bus person capacity The Question How many people can be carried at the street s maximum load point The Facts Y Same assumptions as Example Problem 6 Y A All buses are 43 passenger buses Y Ten buses are express buses operating on freeways The operator s policy is to not allow standees on these buses Y The remaining local buses allow standees Comments Y Assume maximum schedule loads for the local buses equivalent to a load factor of 1 50 for standard buses Y The peak hour factor is 0 75 Outline of Solution The person capacity at the street s maximum load point is equal to the street s bus vehicle capacity times the allowed passenger load per bus times the peak hour factor From Example Problem 6 the street s bus vehicle capacity is 50 buses per hour Steps 1 Calculate the street s bus person P 10 43 30 43 1 50 0 75 capacity at its maximum load point P 1 770 people under the proposed operation 2 Calculate the street s maximum bus P 10 43
43. the traffic stream and accelerate This re entry delay is variable and depends on the traffic volume in the travel lane adjacent to the stop and increases as traffic volumes increase The delay also depends on the platooning effect from upstream traffic signals Some states have passed laws requiring motorists to yield to buses re entering a roadway depending on how well motorists comply with these laws the re entry delay can be reduced or even eliminated Many bus operators avoid using off line stops on busy streets in order to avoid this re entry delay Bus Stops A bus stop is an area where one or more buses load and unload passengers It consists of one or more loading areas Bus stop vehicle capacity is related to the vehicle capacity of the individual loading areas at the stop the bus stop design and the number of loading areas provided Off line bus stops provide greater vehicle capacity than do on line stops for a given number of loading areas but in mixed traffic situations bus speeds may be reduced if heavy traffic volumes delay buses exiting a stop The design of off street bus terminals and transfer centers entails additional considerations Bus Terminals The design of a bus terminal or transit center involves not only estimates of passenger service times of buses that will use the center but also a clear understanding of how each bus route will operate Therefore such factors as schedule recovery times driver relief times
44. turns may queue behind buses at a near side bus stop to make a right turn Conversely right turning traffic may block buses or preempt signal green time from them The interference of right turning traffic on bus operations can be further magnified by significant pedestrian crossing volumes blocking right turn movements The placement of the bus stop at the intersection whether near side far side or mid block can also influence the amount of delay induced by and to the right turning traffic The conflicts between buses and right turns are greatest where there is a near side stop and buses are unable to freely use the bus lane Automobiles turning right may block access to the bus stop conversely buses boarding or discharging passengers on the green signal indication may block right turns The amount of interference diminishes as the distance between the stop line and bus stop increases Far side or mid block stops therefore minimize the effects of right turns on bus speeds when buses can use the adjacent lane Placing stops at locations where there are no right turns can further minimize impacts Right turns are usually prohibited with dual or contra flow bus lanes Just as right turns across bus lanes can delay buses along the arterial pedestrians crossing side streets next to the bus lane can cause delays to the right turning vehicles This in turn can cause increased delays to buses in the bus lane The delays introduced by pedestrian
45. when that lane operates above 75 of its capacity Exhibit 2 49 Typical Values of Adjustment Factor f for Availability of Adjacent Lanes R29 Adjacent Condition Lanevc a NM 1 K f Type 1 Bus Lane Stops every block Otoi Otot 0 0 1 00 pe 49US Ane s Stops every block 0 to 1 0 to 1 0 0 1 00 Alternating 2 block stops random 0 1 1 0 50 0 75 1 0 2 1 0 50 0 55 Alternating 2 block stops typical 0 1 1 0 75 0 88 1 0 2 1 0 75 0 58 Alternating 2 block stops platooned 0 1 1 1 00 1 00 1 02 1 1 00 0 60 Type 3 Bus Lane Alternating 2 block stops random 0 1 1 0 50 0 75 Alternating 2 block stops random 1 1 0 75 0 88 Alternating 2 block stops random 0 1 1 1 00 1 00 Alternating 3 block stops random 0 1 2 0 50 0 67 Alternating 3 block stops random 0 1 2 0 75 0 83 Alternating 3 block stops random 0 1 2 100 1 00 approximate Exhibit 2 50 Values of Adjustment Factor fx for Type 2 Bus Lanes with Alternate Two Block Skip Stops Arrival Pattern Adjacent Lane vic Random Typical Platooned 0 0 0 75 0 88 1 00 0 5 0 72 0 84 0 95 0 6 0 71 0 81 0 92 0 7 0 68 0 77 0 87 0 8 0 65 0 71 0 80 0 9 0 60 0 65 0 71 1 0 0 55 0 58 0 60 Part 2 BUS TRANSIT CAPACITY Page 2 49 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Qual
46. 0 2 35 200 100 300 3 40 100 100 500 4 20 300 50 200 Comments Y The base saturation flow rate vo is 1900 pv hg In Y The bus blockage factor saturation flow adjustment factor feb is 0 84 Y The heavy vehicle saturation flow adjustment factor fav is 0 971 Y The area saturation flow adjustment factor is 0 90 for a CBD Y The bus stop location factor f is 0 90 Type 2 lane near side stop from Exhibit 2 48 Y Foron line stops assume a 10 second clearance time Y Zaz 1 44 for 7 5 failure rate from Exhibit 2 15 Y Assume 60 coefficient of variation of dwell times Y Fortwo linear on line berths the number of effective berths Nes is 1 85 from Exhibit 2 17 Outline of Solution All input parameters are known The critical bus stop will determine the bus lane capacity Because of the variety of dwell times right turn volumes and conflicting pedestrian volumes the critical stop is not immediately obvious The vehicle capacity of each stop must be found first which will then be modified by the number of effective loading areas at each stop and the mixed traffic adjustment factor from Equation 2 18 Steps 1 Calculate the right turn saturation adjustment factor for each stop using the procedures from the Highway Capacity Manual The factor is related to the pedestrian volume and the proportion of right turns from the lane The right turn lane volume used is the sum of the through au
47. 0 1 2 4 1 3 8 950 1 At 1380 person minute increase The proposed exclusive arterial street bus lane will reduce peak hour person delay by 1660 person minutes Buses will be able to traverse the section 1 6 minutes faster than before through automobiles will be slowed by only 0 3 minutes and diverted right turning vehicles will be slowed by 1 0 minute Page 2 86 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Example Problem 9 The Situation A transit operator would like to implement queue jump signal Implementing a queue jump at a priority at a signalized intersection on a city arterial street The traffic signal city traffic engineer is concerned about how automobile traffic will be affected The Question Compare the change in person delay as a result of the signal priority measure The Facts Y Buses arrive at a near side stop located in a right turn lane during the green signal phase for Main Street Boarding and discharging passengers is completed before the end of the red signal phase for Main Street The proposed queue jump will give eastbound peak direction buses a green indication for three seconds in advance of other traffic moving in the peak direction allowing these buses to merge back into the travel lane ahead of the other vehicles stopped at the signal A detector at the bus stop is used to provide a queue jump signal phase only when a bus occupies the stop The three seconds is take
48. 21 Exhibit 2 19 Bus Stop Maximum Vehicle Capacity Related to Dwell Times and Number Of Loading Areas tue cote ect ec TER cot yere teased AA A 2 21 Exhibit 2 20 Factors Influencing Bus Capacity 2 23 Exhibit 2 21 Suggested Bus Flow Service Volumes for Planning Purposes Flow Rates For Exclusive or Near Exclusive Lane essere enne 2 24 Part 2 BUS TRANSIT CAPACITY Page 2 ii Contents Transit Capacity and Quality of Service Manual Exhibit 2 22 Maximum Bus Passenger Service Volumes For Planning Purposes Hourly Flow Rates Based on 43 Seats Per Bus 2 24 Exhibit 2 23 Characteristics of Bus Transit Vehicles United States and Canada 2 25 Exhibit 2 24 Example Skip Stop Pattern and Bus Stop Signing eee 2 27 Exhibit 2 25 Bus Signal Priority Systems sese 2 28 Exhibit 2 26 Bus Signal Priority Concept 2 29 Exhibit 2 27 Bus Queue Jump Concept sesesessseseeeneeneeneeeeee nennen 2 30 Exhibit 2 28 Bus Queue Jump Example Copenhagen Denmark 2 30 Exhibit 2 29 Curb Extension Concept 2 31 Exhibit 2 30 Curb Extension Example Vienna Austria eese 2 31 Exhibit 2 31 Boarding Island Concept sese 2 32 Exhibit 2 32 Boarding Island Example San Francisco ees 2 32 Exhibit 2 33 General Planning Guidelines for Bus Priority Treatments Arterials 2 34 Exhibit 2 34 International Busway Examples
49. 3 Exclusive Arterial Street Bus Lane Example Portland OR 2 3 Exhibit 2 4 Mixed Traffic Example Portland OR 2 4 Exhibit 2 5 Typical Demand Response Vehicle eee 2 4 Exhibit 2 6 Relationship Between Person and Vehicle Capacity sss 2 5 Exhibit 2 7 Bus Vehicle Capacity Factors sseeeeeeeeeeeeeee nennen 2 6 Exhibit 2 8 On Line and Off Line Loading Areas sese 2 7 Exhibit 2 9 On Street Bus Stop Locations sese 2 10 Exhibit 2 10 On Street Bus Stop Location Comparison eee 2 11 Exhibit 2 11 Person Capacity Factors eene eene 2 13 Exhibit 2 12 Person Capacity Calculation Process eese 2 14 Exhibit 2 13 Typical Bus Passenger Boarding and Alighting Service Times for Selected Bus Types and Door Configurations Seconds per Passenger 2 16 Exhibit 2 14 Average Bus Re Entry Delay into Adjacent Traffic Stream Random Vehicle Arrival csv sees pr pb ete D Re prece a estet ee ees 2 18 Exhibit 2 15 Values of Percent Failure Associated With Z esseeeee 2 19 Exhibit 2 16 Estimated Maximum Capacity of Loading Areas Buses h 2 20 Exhibit 2 17 Efficiency of Multiple Linear Loading Areas at Bus Stops 2 20 Exhibit 2 18 Estimated Maximum Capacity of On Line Linear Bus bus h 2
50. 32 Boarding Island Example San Francisco Part 2 BUS TRANSIT CAPACITY Page 2 32 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Other Measures Other transit preferential treatments at intersections include the following e Parking Restrictions These are used in areas where high parking turnover interferes with the flow of traffic on a street Restricting parking will improve transit and traffic flow but the impacts to adjacent land uses from the loss of on street parking must also be considered Parking restrictions are sometimes applied during peak hours only often in conjunction with bus lane operations e Bus Stop Relocation On streets with good traffic signal progression for passenger vehicles moving a bus stop from the near side of an intersection to the far side or vice versa may allow buses to use the signal timing to their advantage passing through intersections on a green signal and dwelling on a red signal e Turn Restriction Exemptions The most direct route for a bus may not be possible because of left turn restrictions at intersections particularly where there is insufficient room to develop left turn lanes If the restriction is due to traffic congestion rather than safety it may be feasible to exempt buses from the restriction without unduly impacting intersection operations Bus Preferential Treatments on Roadway Segments Arterial Bus Lanes Where there is a relatively high vol
51. Equation 2 2 adjusts hourly passenger volumes to reflect peak within the peak conditions PHF E 4P Equation 2 1 inc P 4 PHF 15 Equation 2 2 Best for evaluating existing bus routes See Appendix A for details Best for future planning when reliable passenger estimates are unavailable Suitable when passenger counts or estimates are available Part 2 BUS TRANSIT CAPACITY Page 2 15 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual where PHF peak hour factor P passenger volume during the peak hour p and Pis passenger volume during the peak 15 minutes p Step 3 Determine the base passenger boarding and alighting time This time can be estimated using values given in Exhibit 2 13 or by using the following values for typical operating conditions single door loading pay on bus Boarding 2 0 seconds pre payment includes bus pass free transfer pay on leave 2 6 seconds single ticket token 3 0 seconds exact fare Add 0 5 seconds to the above boarding times if standees are present on the bus Alighting 1 7 to 2 0 seconds Exhibit 2 13 Typical Bus Passenger Boarding and Alighting Service Times for Selected Bus Types and Door Configurations Seconds per Passenger Available Doors or Typical Boarding Typical Channels Service Times s Alighting Service Times Bus Type Number Location Prepayment 5 Coin Fare s C
52. Exhibit 2 60 or Appendix B Ts skip stop speed adjustment factor from Equation 2 17 and fo bus bus interference factor from Exhibit 2 55 Part 2 BUS TRANSIT CAPACITY Page 2 62 Chapter 5 Mixed Traffic NOTE Transit Capacity and Quality of Service Manual Exhibit 2 60 Estimated Bus Speeds V km h Mixed Traffic CBD Central City Suburbs Stops Delay Delay Delay km 1 9 min km 0 6 min km 0 4 min km 10 second dwell time 1 2 17 9 29 3 31 2 2 5 15 4 23 2 24 3 3 7 13 5 19 0 19 8 5 0 11 6 15 4 16 1 62 9 7 12 2 12 6 20 second dwell time 1 2 16 9 26 6 28 2 2 5 14 2 20 0 20 9 3 7 11 7 15 8 16 3 5 0 9 7 12 7 13 0 L 62 8 2 10 1 10 3 30 second dwell time 1 2 15 9 24 3 25 6 2 5 12 7 17 5 18 2 3 7 10 5 13 5 14 0 5 0 8 9 10 8 11 1 6 2 7 2 8 5 8 7 40 second dwell time 1 2 15 1 22 5 23 5 2 5 11 7 15 6 16 3 3 7 9 5 11 9 12 2 5 0 7 9 9 5 9 7 6 2 6 4 7 6 7 6 50 second dwell time 1 2 14 3 20 8 21 7 2 5 10 8 14 2 14 6 3 7 8 7 10 6 10 8 5 0 74 8 4 8 5 L 62 5 8 6 6 6 8 60 second dwell time 1 2 13 7 19 5 20 3 2 5 10 1 12 9 13 2 3 7 8 0 9 5 9 7 5 0 6 4 7 6 7 6 6 2 5 3 6 0 6 0 Data based on field measurements Traffic delays shown reflect peak conditions Dwell times are average dwell times Part 2 BUS TRANSIT CAPACITY Page 2 63 An alternative table using U S customary units appears in Appendix B Chapte
53. L CONTROLLER Signal controller detects bus terminates side street green phase early Queue Jump Queue jump treatments allow buses to avoid long queues of vehicles at signalized intersections by using right turn lanes or long off line bus stops to move past much of the queue Buses are exempted from any right turn requirements at the intersection A special right lane signal provides a green indication for a brief period of time before the adjacent regular traffic lanes During this time the bus exits the right lane and merges into the lane to the left ahead of the other traffic that had stopped for the signal Alternatively the bus pulls into the right lane on a red signal and proceeds to a far side off line bus stop on green resulting in reduced delay waiting for the queue in the regular lanes to clear the intersection Exhibit 2 27 illustrates a typical queue jump design while Exhibit 2 28 shows an actual application of a queue jump In Exhibit 2 28 the bus receives priority from a bus lane that ends at a near side bus stop at the intersection In this application a special transit signal the vertical bar indication adjacent to the regular traffic signal is used to give the bus priority rather than a regular traffic signal Part 2 BUS TRANSIT CAPACITY Page 2 29 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual
54. Transit Capacity and Quality of Service Manual PART 2 BUS TRANSIT CAPACITY CONTENTS 1 BUS CAPACITY BASICS scsssssssssssssessssssessessssessessssessessssessessssessessssessesessesees 2 1 SA 2 1 Ib ains E 2 1 Types of Bus Facilities and Service ssssessseeeeeeeneneeeeen 2 3 Factors Influencing Bus Capacity cee eeeescesecesecssecseeceeeneeeeeseeeeseeeeeeseenseenseenaees 2 5 Vehicle Capacity o eere ete E E N S E emai he 2 5 Person Capacity iso e Ree et cete tenete beste Baebes 2 13 Fundamental Capacity Calculations eese 2 15 Vehicle Capacity 5 5 nee bene rette nere ERE ena 2 15 Person Capacity hi ae ite teo epe e ER taie Pes e RP ns 2 22 Planning Applications sss neiseis see nennen nennen nenne ener 2 23 2 OPERATING ISSUES eese esee eee esent nets tasa tata ane tn tasse tata sine to tasas setas n san 2 25 IntrodUCtODz ette eret Re ete RU euis s 2 25 Bus Operations eo dde mee dieto Ute eed Ede 2 25 Passenger Loads i tains Seas Ae SS ERE 2 25 Skip Stop Operation eie oO sensors Ei Erea deesuassetiavass RR REOR 2 26 Roadway Operations sesoses esne d nie de eese Hi eie eade etd 2 28 Bus Preferential Treatments at Intersections 0 0 0 ee ee ees eese cee cess ceeeneeeeeeeeeees 2 28 Bus Preferential Treatments on Roadway Segments esses 2 33 Person Delay Considerations e
55. US TRANSIT CAPACITY Page 2 33 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 2 33 General Planning Guidelines for Bus Priority Treatments Arterials 9 Minimum One Way Minimum One Way Peak Hour Peak Hour Related Land Use and Treatment Bus Volumes Passenger Volumes Transportation Factors Bus Streets or Malls 80 100 3 200 4 000 Commercially oriented frontage CBD curb bus lanes 2 000 3 200 Commercially oriented frontage main street eee Curb bus lanes 30 40 1 200 1 600 At least 2 lanes available for other normal flow traffic in same direction Median bus lanes 60 90 2 400 3 600 Atleast 2 lanes available for other traffic in same direction ability to separate vehicular turn conflicts from buses Contraflow bus 800 1 200 Allow buses to proceed on normal lanes short route turnaround or bypass segments congestion on bridge approach Contraflow bus 40 60 1 600 2 400 At least 2 lanes available for other lanes extended traffic in opposite direction Signal spacing greater than 150 meter 500 foot intervals Bus preemption of 10 15 400 600 Wherever not constrained by traffic signals pedestrian clearance or signal network constraints Special bus signals 5 10 200 400 At access points to bus lanes and signal phase busways or terminals or where bus activated special bus turning movements must be accommodated Special bus turn 5 10
56. actors are based on simulation and European experience The exhibit suggests that four or five on line linear loading areas have the equivalent effectiveness of three loading areas Note that to provide two effective on line loading areas three physical loading areas would need to be provided since partial loading areas are never built Once again it should be noted that Exhibit 2 17 applies only to inear loading areas All other types of multiple loading areas are 10096 efficient the number of effective loading areas equals the number of physical loading areas Page 2 20 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual The vehicle capacity of a bus stop in buses per hour is given by Equation 2 5 3 600 g C t g C t Z c t B N B N Equation 2 5 where B maximum number of buses per bus stop per hour and Na number of effective loading areas from Exhibit 2 17 Exhibit 2 18 provides estimated capacities of on line bus stops This exhibit shows the number of buses per hour for various numbers of loading areas dwell times and g C ratios The maximum capacities attainable are 3 0 times those of a single loading area Exhibit 2 18 Estimated Maximum Capacity of On Line Linear Bus bus h Number of On Line Linear Loading Areas 1 2 4 5 gic giC gic gic giC gc
57. and layovers to meet scheduled departure times become the key factors in establishing loading area requirements and sizing the facility In addition good operating practice suggests that each bus route or geographically compatible groups of routes should have a separate loading position to provide clarity for passengers Loading area space requirements should recognize the specific type of transit operations fare collection practices bus door configurations passenger arrival patterns amount of baggage driver layover recovery times terminal design and loading area configuration They should reflect both scheduled and actual peak period bus arrivals and departures since intercity bus services regularly run extras during the busiest seasonal travel periods Bus route and service patterns also influence loading area requirements Good operating practice calls for a maximum of two distinct routes i e services per loading position Part 4 of this manual describes sizing bus terminals in greater detail On Street Bus Stops On street bus stops are typically located curbside in one of three locations 1 near side where the bus stops immediately prior to an intersection 2 far side where the bus stops immediately after an intersection and 3 mid block where the bus stops in the middle of the block between intersections Under certain circumstances such as when buses share a stop with streetcars running in the center of the street
58. art 2 BUS TRANSIT CAPACITY Page 2 34 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Essen Germany and Adelaide Australia are among the few cities to date worldwide that have developed guided busways which allow buses to operate in narrower rights of way and require less steering on the part of the driver An extra set of wheels provides lateral guidance for the bus as shown in Exhibit 2 34 One advantage of the lateral guidance is that only the wheel tracks need be paved allowing a grass strip to be planted in the middle of the lane improving the lane s aesthetics Exhibit 2 34 International Busway Examples E TOTEM CUq xD Ls MRSA Rate HER rts fa High Level Curitiba Brazil Guided Busway Essen Germany Queue Bypasses Queue bypasses are a form of priority treatment that allow buses to avoid queues of Queue bypasses vehicles such as those that develop at freeway ramp meters by providing a special lane that avoids the queue Exhibit 2 35 depicts a typical queue bypass design on a freeway on ramp and Exhibit 2 36 shows an actual application Exhibit 2 35 Freeway Ramp Queue Bypass Concept Cars queue at ramp meter BUS ONLY Bypass lane allows bus to avoid queue Part 2 BUS TRANSIT CAPACITY Page 2 35 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 2 36 Freeway Ramp Queue Bypass Example Los Angeles As with arterial s
59. art 2 BUS TRANSIT CAPACITY Page 2 73 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Number of bus berths required at a stop Part 2 BUS TRANSIT CAPACITY Example Problem 2 The Situation A downtown Type 2 exclusive bus lane currently serves 32 buses during the evening peak hour The transit agency wishes to add another route to the corridor with 10 minute headways during the peak hour The Question What is the existing bus vehicle capacity along the corridor Will additional loading areas be required at the busiest stop and if so how many The Facts Y The g C ratio the ratio of effective green time to cycle length along the route is 0 45 Y A All bus stops are on line and currently have one linear berth each Y Average bus dwell time at the critical stop is 30 seconds Y The desired bus stop failure rate is 1096 Y Right turns are prohibited along the street Comments Y Assume C the coefficient of variation in dwell times is 0 60 Y For on line stops assume a 10 second clearance time Outline of Solution All input parameters are known As right turns are prohibited the vehicle capacity of the critical bus stop will determine the bus lane vehicle capacity i e f from Equation 2 9 is 1 The vehicle capacity of a linear bus stop is the vehicle capacity of a loading area times the number of effective loading areas Steps 1 Calculate the vehicle capacity of a single berth
60. ation of vehicle capacity Skip Stop Operations The analytical method intrinsically accounts for skip stop operations by considering only the bus stops in the skip stop pattern For example if bus stops are located at each intersection 125 meters 400 feet apart the two block skip stop distance is 250 meters 800 feet Thus a bus with a two block stop pattern can proceed along the arterial at about twice the speed of a one block stop pattern and a three block stop pattern at about three times the speed assuming uniform block distances and dwell times Part 2 BUS TRANSIT CAPACITY Page 2 54 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Exhibit 2 53 Estimated Arterial Street Bus Speeds Vo km h Without Single Normal Flow Bus Lanes Dual Contraflow Traffic Delays CBD Central City Suburbs Bus Lanes Stops Delay Delay Delay Delay Delay km Omin km 1 2 min km 0 4 min km 0 3 min km 0 7 min km 10 second dwell time 12 40 2 21 9 32 2 33 3 26 2 2 5 29 5 18 3 24 9 25 6 21 6 3 7 23 0 15 6 20 1 20 6 17 5 5 0 18 2 13 2 16 3 16 6 14 8 6 2 13 8 10 8 12 6 12 9 11 7 Co o 20 second dwell time 1 2 35 4 20 4 29 0 29 9 24 6 2 5 24 6 16 3 21 2 21 7 18 8 3 7 18 5 13 4 16 6 16 9 14 8 5 0 14 5 11 1 13 4 13 5 12 2 62 111 t 90 10 5 10 5 9 8 30 second dwell time 12 31 4 19 0 26 2 270 22 5 2 5 20 9 17 2 18 5 19 0 16 6 3
61. ber of people boarding and or alighting through the highest volume door is the key factor in how long it will On line vs off line loading areas Elements affecting loading area vehicle capacity Dwell time is the single most important factor affecting vehicle capacity Part 2 BUS TRANSIT CAPACITY Page 2 7 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Wheelchair and bicycle boarding times may also need to be considered when calculating dwell time take for all passengers to be served If standees are present on board a bus as it arrives at a stop or if all seats become filled as passengers board service times will be higher than normal because of congestion in the bus aisleway The mix of alighting and boarding passengers at a stop also influences how long it takes all passenger movements to occur e Bus Stop Spacing The fewer the stops the greater the number of passengers who will need to board at a given stop A balance is required between too few stops which increase the distance riders must walk to access transit and increase the amount of time an individual bus occupies a stop and too many stops which reduce overall travel speeds due to the time lost in accelerating decelerating and possibly waiting for a traffic signal every time a stop is made e Fare Payment Procedures The amount of time passengers must spend paying fares is a major factor in the total time required per boarding pa
62. bus lane operations on the adjacent general travel lane can be expressed by multiplying the adjacent lane s vehicle capacity by the adjustment factor given in Equation 2 14 derived from simulation The factor is applied to saturation flow similar to the other saturation flow adjustments including the factor for bus blockage f 1 4 7 3600 Equation 2 14 where tp bus passing activity factor and N number of buses making the maneuver from the curb lane to the adjacent lane from Equation 2 15 Part 2 BUS TRANSIT CAPACITY Page 2 52 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual The delay to through traffic in the adjacent lane is minimal unless buses leave the bus lane Therefore an adjustment is needed to determine the actual number of buses N that would pass other buses using the curb lane Simulations and field observations indicate that when buses operate at less than one half the vehicle capacity of the bus lane they have little need to pass each other even in a skip stop operation because of the low arrival headways relative to capacity Bus use of the adjacent lane increases at an increasing rate as bus activity approaches capacity Thus N may be approximated by the following relationship A as gol pe C Equation 2 15 where N number of stops skipped Vp volume of buses in the bus lane and Cp bus vehicle capacity of the bus lane As
63. bus stop without requiring an extra berth How much room for additional growth in bus volumes will there be How will bus operating speeds be affected The Facts Y Same assumptions as Example Problem 2 Y There are two groups of routes NE Metro 25 buses and NW Metro 13 buses Buses arrive randomly within each group 500 veh h use the adjacent lane Trucks comprise 2 of the traffic in the adjacent lane Bus stops are located on the near sides of intersections Average dwell time for both groups of routes is 30 seconds Stops are spaced 200 meters apart 5 stops km SONUS Comments Y The Highway Capacity Manual should be used to determine the capacity of the adjacent lane The base saturation flow rate vo is 1900 passenger vehicles per hour of green The heavy vehicle saturation adjustment factor fav is 0 98 The area saturation flow adjustment factor fa is 0 90 for CBDs Outline of Solution All input parameters are known Since the larger of the two groups of buses has 25 buses per hour and the critical stop can accommodate 35 buses per hour from Example Problem 2 the skip stop pattern will provide sufficient capacity for each group without requiring additional berths at stops The bus lane vehicle capacity is equal to the sum of the vehicle capacities of the two bus stop patterns times an adjustment factor for the effect of random bus arrivals and the impedance of other traffic in the adjacent lane The speed estimation
64. bus stops are lengthened to accommodate two berths otherwise the capacity should be based on the critical one berth stop The base bus speed Vo is calculated from Exhibit 2 53 using the dual bus lane column since the capacity calculations took right turn interferences into account Under the skip stop scenario the skip stop speed adjustment factor must be calculated from Equation 2 17 The larger of the two patterns bus v c ratios should be used in the calculation 0 71 By interpolation fp 0 88 using the larger of the two patterns bus v c ratios The base bus speed and the bus travel speed under the skip stop scenario are calculated similarly to Step 5 For comparison the existing bus speeds on the street 32 buses and single loading areas are Page 2 76 9 thus vy cs 25 35 1 Ka N 1 k7 N 1 0 50 0 77 2 1 f 2 f 9 69 B f B B B 0 69 35 35 B 48 bus h V V f f V 10 5 km h 1 0 0 95 V 210 0 km h T X98 E 10 ACQUE f V Vf f V 10 5 km h 0 84 0 88 V 7 8 km h V V f fs V 10 5 km h 1 0 0 67 V 7 0 km h t Chapter 8 Example Problems Transit Capacity and Quality of Service Manual The Results Both options provide sufficient vehicle capacity to accommodate the proposed route modification and both options increase bus travel speeds above existing levels Adding an additional berth to each stop has a greater po
65. city of right turns at specific intersection Suggested factors for the bus stop location factor f are shown in Exhibit 2 48 Where right turns are allowed the factors range from 0 5 for a far side stop with the adjacent lane available for buses to 1 0 for a near side stop with all buses restricted to a single lane A factor of 0 0 is used for Type 3 lanes as right turns are not allowed by non transit vehicles from this type of bus lane These factors reflect the likely ability of buses to move around right turns Note that at critical intersections on some bus lanes all turns can be prohibited and pedestrian walk signals delayed Exhibit 2 48 Bus Stop Location Factors f r Bus Lane Type _ l Bus Stop Location Type 1 Type 2 Type 3 l Near side 1 0 0 9 0 0 Mid block 0 9 0 7 0 0 Far side 0 8 0 5 i 0 0 NOTE f 0 0 for contra flow bus lanes and median bus lanes regardless of bus stop location or bus lane type as right turns are either prohibited or do not interfere with bus operations Skip Stop Adjustment Factor The total number of buses per hour that can be accommodated by a series of split stops represents the sum of the capacities of bus routes using each stop multiplied by a impedance factor f reflecting non platooned arrivals and the effects of high volumes of vehicular traffic in the adjacent lane Equation 2 10 represents the factors that impede buses from fully uti
66. ding area per hour is R29 3 600 g C U t g O t Z c t av Equation 2 4 where By maximum number of buses per loading area per hour g C ratio of effective green time to total traffic signal cycle length 1 0 for a stop not at a signalized intersection te clearance time between successive buses s ta average mean dwell time s La one tail normal variate corresponding to the probability that queues will not form behind the bus stop and Cy coefficient of variation of dwell times Exhibit 2 16 presents the estimated number of buses that can use a bus loading area for g C ratios of 0 5 and 1 0 the ratio of green signal time to the total traffic signal cycle length Values are tabulated for dwell times ranging from 15 to 120 seconds Values for g C times between 0 5 and 1 0 can be interpolated values for g C times less than 0 5 and for other dwell times can be computed directly from Equation 2 4 These maximum capacities assume adequate loading area and bus stop geometry Guidelines for the spacing location and geometric design of bus stops are given in TCRP Report 19 99 These guidelines must be carefully applied to assure both good traffic and transit operations Part 2 BUS TRANSIT CAPACITY Suggested design failure rates Loading area vehicle capacity Page 2 19 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Sawtooth and other non linear design
67. ds while the ramps used in low floor buses reduce the cycle times to 30 to 60 seconds including the time required to secure the wheelchair inside the bus The higher cycle times relate to a small minority of inexperienced or severely disadvantaged users When wheelchair users regularly use a bus stop to board or alight the wheelchair lift time should be added to the dwell time Impact of Bicycles on Dwell Time Some transit systems provide folding bicycle racks on buses When no bicycles are loaded the racks typically fold upright against the front of the bus Some systems also use rear mounted racks and a very few allow bikes on board on certain long distance routes When bicycles are loaded passengers deploy the bicycle rack and load their bicycles into one of the available loading positions typically two are provided The process takes approximately 20 to 30 seconds When bicycle rack usage at a stop is frequent enough to warrant special treatment a bus dwell time is determined using the greater of the passenger boarding alighting time or the bicycle loading unloading time Clearance Time Clearance time includes two components 1 the time for a bus to start up and travel its own length while exiting a bus stop and for off line stops 2 the re entry delay associated with waiting for a sufficient gap in traffic to allow a bus to pull back into the travel lane Various studies have evaluated these factors either singly or as a who
68. e Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Exhibit 2 46 Type 2 Exclusive Bus Lane Examples Portland OR Salzburg Austria Exhibit 2 47 Type 3 Exclusive Bus Lane Examples New York Miami single lane with off line stops Part 2 BUS TRANSIT CAPACITY Page 2 46 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual CALCULATING VEHICLE CAPACITY The vehicle capacity of an exclusive bus lane depends on several factors e the bus lane type e whether or not skip stop operation is used e whether or not buses using the lane are organized into platoons e the volume to capacity ratio of the adjacent lane for Type 2 bus lanes and e bus stop location and right turning volumes from the bus lane If no special bus operational procedures such as skip stops are used and if right turns are prohibited by non transit vehicles then the bus lane vehicle capacity is simply the vehicle capacity of the critical bus stop along the bus lane However when skip stops are used or when right turns are allowed then adjustments must be made to this base vehicle capacity as described in the following sections Effects of Right Turns Right turning traffic physically competes with buses in the bus lane for space at an intersection The traffic generally turns from the bus lane although in some cases as in Houston some right turns are made from the adjacent lane The right
69. e jump should be viewed favorably Part 2 BUS TRANSIT CAPACITY Page 2 88 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual APPENDIX A DWELL TIME DATA COLLECTION PROCEDURE INTRODUCTION As discussed in Chapter 1 passenger service times and dwell times can vary greatly depending on many factors For example passenger service times reported in the literature range from 1 to 10 seconds per passenger 5 F For this reason it is recommended that field data be collected to develop procedures for estimating passenger service times and dwell times for a given system Although the passenger service time of a transit vehicle may be affected by many factors most of these factors are constant for a given system For this reason the principal determinants of service time typically include aspects of passenger demand Therefore for a given transit system with constant operating characteristics i e fare collection system number and width of doors number of steps to board alight etc the major factors affecting service time will include e number of passengers boarding e number of passengers alighting and e number of passengers on board The following are methodologies to measure passenger service times and dwell times for buses and light rail transit LRT in the field PASSENGER SERVICE TIMES Passenger loadings at most stops are small typically one or two per stop In these situations dwells are re
70. e most accurate way to determine bus dwell times at a stop is to measure them directly An average mean dwell time and its standard deviation can be determined from a series of observations Appendix A presents a methodology for measuring bus dwell times in the field Method 2 Default Values If field data or passenger counts are unavailable for a bus stop the following representative values can be used to estimate dwell time 60 seconds per CBD transit center major on line transfer point or major park and ride stop 30 seconds per major outlying stop and 15 seconds per typical outlying stop Method 3 Calculation This method requires that passenger counts or estimates be available categorized by the number of boarding and alighting passengers Step 1 Obtain hourly passenger volume estimates These estimates are required only for the highest volume stops When skip stop operations are used estimates are needed for the highest volume stops in each skip stop sequence Step 2 Adjust hourly passenger volumes for peak passenger volumes Equation 2 1 shows the peak hour factor PHF calculation method Typical peak hour factors range from 0 60 to 0 95 for transit lines A PHF close to 1 0 may well indicate system overload underservicing and reveal the potential for more service If buses operate at less than 15 minute headways the denominator of Equation 2 1 should be adjusted appropriately e g 3P29 for 20 minute headways
71. e relationship between the vehicle capacity of bus facilities and the elements of person capacity described above is illustrated in Exhibit 2 12 Exhibit 2 12 Person Capacity Calculation Process Bus Lane X Paule X Peak Hour BusLane Person Capacity Vehicle Capacity Loading Factor E at Maximum Load Point Route X Bassenact X Peak Hour _ Bus Route Person Capacity Frequency Loading Factor B at Maximum Load Point Peak 15 min Bus Stop Peak Hour Bus Stop P enger Interch e Vehicle Capacity X Vol re p r Vehicle Factor Person Capacity Part 2 BUS TRANSIT CAPACITY Page 2 14 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual FUNDAMENTAL CAPACITY CALCULATIONS Regardless of the kind of bus facility being analyzed there are some fundamental capacity calculations common to each This section presents these calculation procedures which will be used throughout Chapters 3 5 Vehicle Capacity Dwell Time Three methods can be used to determine bus dwell times 1 Field measurements This method is best suited for determining the capacity of an existing bus route 2 Default values This method is best suited for future planning when reliable estimates of future passenger boarding and alighting volumes are not available 3 Calculation This method is suitable for estimating dwell times when passenger boarding and alighting counts or estimates are available Method 1 Field Measurements Th
72. e section below discusses these categories in further detail e Chapter 7 contains references for material presented in Part 2 which may be consulted for further information on how the procedures were developed e Chapter 8 presents example problems that illustrate how to apply the procedures introduced in Part 2 to real world situations e Appendix A provides a procedure for collecting bus dwell time data in the field e Appendix B provides substitute exhibits in U S customary units for Part 2 exhibits that use metric units Definitions Throughout Part 2 the distinction is made between vehicle and person capacity Vehicle capacity reflects the number of buses that can be served by a loading area bus stop bus lane or bus route during a specified period of time Person capacity reflects the number of people that can be carried past a given location during a given time period under specified operating conditions without unreasonable delay hazard or restriction and with reasonable certainty This definition of person capacity is less absolute than definitions of vehicle capacity because it depends on the allowable passenger loading set by operator policy and the number of buses operated Because the length of time that passengers remain on a bus affects the total number of passengers that may be carried over the entire length of a route person capacity is often measured at a route s maximum load point For example an express bus
73. e vehicle also provides the door to door ADA service for those passengers who have difficulty traveling on their own to the nearest bus stop Two types of deviated fixed route transit are commonly used Route deviation requires the bus to follow the entire fixed route so as not to miss potential passengers waiting along the route but allows the bus to travel off the route a fixed distance to pick up and drop off passengers as long as the bus returns to the fixed route at the same point Part 2 BUS TRANSIT CAPACITY Page 2 66 Chapter 6 Demand Responsive Transit Capacity and Quality of Service Manual it left it Point deviation requires only that a bus be at certain locations at certain times The bus may follow a set route when no deviations are requested but it is not obligated to return to the route at the same point it left See Exhibit 2 63 Exhibit 2 63 Deviated Fixed Route Service Patterns Point Deviation Scheduled Route Timepoint ture Actual Route Pick up Drop off Route Deviation CALCULATING VEHICLE CAPACITY Demand responsive service capacity is different than capacity for other kinds of bus service in that the issue is not how many vehicles can a facility accommodate as the number of vehicles being operated in any given service is generally very small Rather the question being asked is how many vehicles are required to accommodate a given passenger demand and service area For many to one a
74. ective loading areas at the critical bus stop and fu capacity adjustment factor for mixed traffic interference at the critical bus stop Exhibit 2 59 illustrates how bus vehicle capacity declines as curb lane traffic volumes increase and how bus vehicle capacity varies by bus stop location It should also be noted that in mixed traffic situations off line linear stops may provide less bus vehicle capacity than on line stops for identical dwell times as the additional fractional effective loading areas provided by off line stops are outweighed by the additional delay buses encounter when re entering traffic Exhibit 2 59 Illustrative Mixed Traffic Maximum Bus Vehicle Capacity 60 a o RB eo 20 Curb Lane Bus Vehicle Capacity bus h eo 10 0 0 100 200 300 400 500 600 700 800 900 Curb Lane Traffic Volume pv h Near side on line Mid block on line Far side on line Near side off line Mid block off line Far side off line NOTE Assumes a Type 1 mixed bus lane one linear loading area per stop g C 0 5 30 second dwell time 25 failure rate and a 60 coefficient of variation CALCULATING PERSON CAPACITY The person capacity of buses operating in mixed traffic at the lane s maximum load point may be calculated by multiplying the vehicle capacity given by Equation 2 19 by the maximum passenger loads allowed by policy times a peak h
75. eds of Buses Operating in Freeway HOV Lanes km h SS NOTE Assumes constant 1 2 m s acceleration deceleration rate Part 2 BUS TRANSIT CAPACITY Page 2 43 Stop Dwell Time s Spacing km 15 30 45 60 80 km h Running Speed 1 5 53 4 46 6 41 2 37 0 2 5 61 6 55 9 51 1 47 1 3 0 64 1 58 9 54 4 50 6 4 0 67 4 63 0 59 1 55 7 5 0 69 6 i 65 8 i 62 4 59 3 90 km h Running Speed 1 5 56 4 48 7 42 9 38 4 2 5 66 3 59 7 54 3 49 8 3 0 69 3 63 2 58 1 53 8 4 0 73 5 68 3 63 8 59 8 5 0 76 3 i 71 8 i 67 7 64 1 100 km h Running Speed 1 5 58 6 50 4 44 2 39 4 2 5 70 3 62 8 56 9 52 0 3 0 73 9 67 0 61 3 56 5 4 0 79 1 73 0 67 9 63 4 5 0 82 5 i 77 2 i 72 5 68 4 Transit Capacity and Quality of Service Manual An alternative table using U S customary units appears in Appendix B Chapter 3 Busways and Freeway HOV Lanes Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 44 Chapter 3 Busways and Freeway HOV Lanes Transit Capacity and Quality of Service Manual 4 EXCLUSIVE ARTERIAL STREET BUS LANES INTRODUCTION This chapter presents methodologies for analyzing the operation of buses using exclusive arterial street bus lanes The key characteristics of this kind of facility are 1 at least one lane reserved exclusively for use by buses except possibly at intersections and 2 interrupted flow Freeway HOV lane
76. eeway HOV Lanes Transit Capacity and Quality of Service Manual Exclusive busways with a limited number of CBD stops have passenger distribution characteristics similar to subways CALCULATING VEHICLE CAPACITY Freeway HOV Lanes Freeway HOV lanes are designed to increase the potential person capacity of a freeway by reserving one or more lanes either part time or full time for the use of vehicles with multiple occupants When the regular freeway lanes experience congestion vehicles in the HOV lane should still travel freely As a result persons in the HOV lane are provided a time savings benefit compared to persons driving alone In order to maintain this time savings incentive and to continue to move more people through the freeway segment than would be possible without the HOV lane HOV lanes should not operate at or near capacity The level of service provided to persons traveling in an HOV lane should be better during peak periods than the level of service provided to vehicles traveling in the regular freeway lanes This level of service can be calculated using the procedures given in the HCM chapters related to freeways Calculating the theoretical bus capacity or service volume for freeway HOV lanes used exclusively by buses is not practical because 1 no North American transit agency schedules so many buses as to come close to the bus vehicle capacity of a basic freeway segment and 2 the number of buses that can actually be
77. eferable Far side stops are also used at intersections where buses make left turns and at intersections with one way streets moving from left to right Mid block stops are typically only used at major passenger generators or where insufficient space exists at adjacent intersections 7 Part 2 BUS TRANSIT CAPACITY Page 2 10 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Exhibit 2 10 compares the advantages and disadvantages of each kind of bus stop location Exhibit 2 10 On Street Bus Stop Location Comparison Location Advantages Disadvantages Far Side Minimizes conflicts between right e May result in intersections being turning vehicles and buses blocked during peak periods by Provides additional right turn stopped buses capacity by making curb lane May obscure sight distance for available for traffic crossing vehicles Minimizes sight distance May increase sight distance problems on intersection problems for crossing pedestrians approaches e Can cause a bus to stop far side after Encourages pedestrians to cross stopping for a red light interfering behind the bus with both bus operations and all other Creates shorter deceleration traffic distances for buses since the May increase the number of rear end intersection can be used to crashes since drivers do not expect decelerate buses to stop again after stopping at Buses can take advantage of a red light gaps in traffic f
78. ervoir on approach Jat toll plazas to toll plaza Exclusive bus 10 15 400 600 access to non reserved freeway or arterial lane Bus bypass lane at 10 15 400 600 Alternate surface street route metered freeway available for metered traffic ramp Express buses leave freeways to make intermediate stops Bus stops along 5 10 50 100 Generally provided at surface freeways street level in conjunction with metered ramp Boarding or alighting passengers in the peak hour Person Delay Considerations In many cases providing transit priority treatments involves tradeoffs among the various users of a roadway facility Providing a bus queue jump at a traffic signal for example provides a time savings benefit for bus passengers while causing additional delay for motorists their passengers bicyclists and some pedestrians When considering implementing transit priority treatments one factor to consider should be the net change in person delay to all roadway users as a result of the priority treatment Of course other factors such as cost change in transit quality of service and local policies encouraging greater transit use should also be considered An example problem in Chapter 8 illustrates how to evaluate the net change in person delay resulting from implementing a transit signal priority measure Roadway Operations Summary Exhibit 2 39 summarizes the advantages and disadvantages of the transit preferential treat
79. f Service Exhibit 2 44a Estimated Average Speeds of Buses Operating in Freeway HOV Lanes mph 0058558585955 NOTE Assumes constant 4 ft s acceleration deceleration rate Part 2 BUS TRANSIT CAPACITY Page 2 93 Stop Dwell Time s Spacing mi 15 30 45 60 50 mph Running Speed 1 0 34 2 29 9 26 6 23 9 1 5 38 2 34 5 31 5 29 0 2 0 40 6 37 4 34 7 32 4 2 5 42 2 39 4 37 0 34 8 3 0 43 3 40 9 38 7 36 7 55 mph Running Speed 1 0 35 8 31 1 27 6 24 7 1 5 40 5 36 4 33 0 30 3 2 0 43 3 39 8 36 7 34 1 2 5 45 3 42 1 39 3 36 9 3 0 46 6 i 43 8 i 41 3 39 0 60 mph Running Speed 1 0 37 1 32 1 28 3 25 3 1 5 42 5 38 0 34 4 31 4 2 0 45 8 41 8 38 5 35 6 2 5 48 1 44 5 41 5 38 8 3 0 49 8 i 46 5 i 43 7 41 2 Appendix B Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual Exhibit 2 53a Estimated Bus Speeds V mph Exclusive Arterial Street Bus Lanes Without Single Normal Flow Bus Lanes Dual Contraflow Traffic Delays CBD Central City Suburbs Bus Lanes Stops Delay Delay Delay Delay Delay mi 0 min mi 2 0 min mi 0 6 min mi 0 5 min mi 1 2 min mi 10 second dwell time 2 25 0 13 6 20 0 20 7 16 3 4 18 3 11 4 15 5 15 9 13 4 6 14 3 9 7 12 5 12 8 10 9 8 11 3 8 2 10 1 10 3 9 2 10 8 6 6 7 7 8 8 0 7 8 20 second dwell time 2 22 0 12 7 18 0 18 6 15 3 4 15 3 10 1 13
80. f Service Manual 5 MIXED TRAFFIC INTRODUCTION Buses operating in mixed traffic situations is the most common operating scenario in North American cities and rural areas and applies to small and large buses both standard and articulated and to both fixed route and demand responsive services The unusual exceptions occur in larger cities with very high capacity routes which may lend themselves to busways or downtown bus lanes Because buses operate much like other vehicles in a traffic lane their impact on the overall vehicle capacity of the lane may be calculated as if they were another vehicle using the procedures given in the Highway Capacity Manual and using a vehicle equivalence of 2 0 9 The lane s bus vehicle capacity is calculated in a similar manner as for exclusive arterial street bus lanes except that the interference of other traffic on bus operations must be accounted for This traffic interference is greatest when off line stops are used and buses must wait for a gap in traffic to merge back into the street BUS LANE TYPES Similar to exclusive arterial street bus lanes the capacity procedures in this chapter define two lane types with the availability of an adjacent lane for buses to pass other vehicles the determining factor Type I mixed traffic lanes have one traffic lane in the direction the bus operates shared by buses and other vehicles Exhibit 2 57 illustrates a Type 1 mixed traffic bus lane Type 2 mixed
81. from Equation 2 4 2 Oneloading area is sufficient to accommodate the existing demand of 32 buses per hour Adding another route with 10 minute headways will result in six more buses per hour which will exceed the critical stop s vehicle capacity Try adding a second linear berth which from Exhibit 2 17 has the effectiveness of 1 85 berths The Results 3 600 g C BUE Wd t dT E 3 600 0 45 104 0 45 30 1 28 0 60 30 B 35 bus h From Equation 2 5 BL N By B 1 85 35 B 65 bus h Adding a second linear berth to the critical bus stop will give it sufficient vehicle capacity to accommodate the new route The new critical bus stop should now be checked to make sure that it too can accommodate the proposed additional buses As a general rule most downtown stops should have two or three berths wherever possible Page 2 74 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Example Problem 3 The Situation It has been suggested that implementing skip stop operations Bus vehicle capacity and speed along the street described in Example Problem 2 could with an exclusive bus lane skip eliminate the need to add berths to existing bus stops and stop operation would increase bus operating speeds for the future scenario of 38 buses during the peak hour The Question Will implementing a two stop skip stop pattern provide sufficient vehicle capacity at the critical
82. ger may be seated Exhibit 2 42 provides illustrative busway person capacities at the busway s maximum load point Exhibit 2 43 shows how the door configuration and number of loading areas increase the maximum load point capacity The left vertical scale applies to through station operations where 50 percent of all passengers board at the heaviest stop The right vertical scale applies to a single station situation where all riders board at the major stop such as at a CBD bus terminal This exhibit can be used to estimate the number of passengers per hour that can be accommodated by various numbers and types of loading areas It can be seen that increasing the number of doors available for boarding e g by using pre paid fares at busway stations or through use of smart card technology greatly increases a busway s person capacity Part 2 BUS TRANSIT CAPACITY Page 2 41 Chapter 3 Busways and Freeway HOV Lanes Transit Capacity and Quality of Service Manual Exhibit 2 43 Typical Busway Line Haul Passenger Volumes 12000 B 10096 Board at Heaviest Stop 8 8 B 5096 Board at Heaviest Stop Hourly Passenger Volumes at Max Load Point Hourly Passenger Volumes at Max Load Point eo 0 1 2 3 4 5 Number of Loading Areas Single channel on line stops Two channels on line stops Six channels on line stops reir Single channel off line stops Two channels off line stops
83. icient of Variation e Generally constant for a given area Failure Rate e Increase the number of loading areas at a stop e Schedule fewer buses per hour using the stop CALCULATED RESULTS Loading Area Capacity e Reduce dwell time e Implement transit priority treatments e Increase the accepted failure rate Increase loading area capacity Use off line loading areas Use sawtooth or pull through loading areas Increase the number of loading areas e Increase the capacity of the critical stop e Reserve lanes for buses e Platoon buses e e Dwell Time Clearance Time Bus Stop Capacity Bus Lane Capacity Implement skip stop operation Prohibit right turns by automobiles Reduce dwell time e Implement transit preferential treatments e Balance the number of stops with passenger convenience and demand e Implement skip stop operation Measures that may negatively affect other items in the list if implemented Measure that improves the failure rate but decreases capacity Bus Speeds The observed peak hour bus movements along freeways and city streets and to or from bus terminals provide guidelines for estimating the capacity of similar facilities They also provide means of checking or verifying more detailed capacity calculations General guidelines for planning purposes follow Suggested arterial street bus service volume varies based on actual operating Roadway bus capacity experie
84. ility that a queue of buses will not form behind a bus stop or failure rate can be derived from basic statistics The value Z represents the area under one tail of the normal curve beyond the acceptable levels of probability of a queue forming at a bus stop Typical values of Z for various failure rates are shown in Exhibit 2 15 A design failure rate should be chosen for use in calculating a loading area s capacity Higher design failure rates increase bus stop capacity at the expense of schedule reliability Capacity occurs under normal conditions at a 25 failure rate Page 2 18 Chapter 1 8Bus Capacity Basics Values of Percent Failure Associated With Z Transit Capacity and Quality of Service Manual Exhibit 2 15 R29 Failure Rate Za 1 0 2 330 2 5 1 960 5 0 1 645 7 5 1 440 10 0 1 280 15 0 1 040 20 0 0 840 25 0 0 675 30 0 0 525 50 0 0 000 Suggested values of Z are the following R29 e CBD stops Z values of 1 440 down to 1 040 should be used They result in probabilities of 7 5 to 15 percent respectively that queues will develop e Outlying stops A Z value of 1 960 should be provided wherever possible especially when buses must pull into stops from the travel lane This results in queues beyond bus stops only 2 5 percent of the time Z values down to 1 440 are acceptable however Loading Areas The maximum number of buses per loa
85. ing a two block A B stop pattern three A pattern buses must arrive at the upstream entry to the section during one signal cycle followed by three B pattern buses Buses alternating stops must also be able to utilize the adjacent traffic lane to bypass stopped buses They may be impeded in this maneuver when the adjacent lane operates at or near capacity Part 2 BUS TRANSIT CAPACITY Page 2 26 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 2 24 Example Skip Stop Pattern and Bus Stop Signing Portland Oregon 5 and 6 Avenue Bus Mall UNO be gaion e Eis E er ay La Be PISIS SI mE o aS 38 e Part 2 BUS TRANSIT CAPACITY 5th Avenue 6th Avenue e 8s Me S m 31 1 54 60 1 9 32 55 88 4 10 33 56 89 5 14 35 57 91X 17 17 38 58 92X 40 19 40 96 SW ASH SW PINE SW OAK SW STARK SW WASHINGTON SW ALDER SW MORRISON SW YAMHILL SW TAYLOR SW SALMON SW MAIN SW MADISON Page 2 27 8 9 10 12 19 33 The Portland 5 and 6th Avenue Bus Mall is depicted on the map 1997 configuration All buses heading to a particular portion of the Portland area use the same stop which is indicated by a colored symbol on maps and bus stops such as the orange deer pictured Local buses stop every two blocks with four sets of stops southbound on Fifth Avenue two in each block and three sets of stops northbound on Sixth Avenue Ex
86. ing guidelines design and operation consult the HOV Systems Manual published by TRB Part 2 BUS TRANSIT CAPACITY Page 2 36 Chapter 2 Operating Issues General Planning Guidelines for Bus Priority Treatments Freeways Transit Capacity and Quality of Service Manual Exhibit 2 38 R21 Minimum One Way Minimum One Way Peak Hour Peak Hour Related Land Use and Treatment Bus Volumes Passenger Volumes Transportation Factors Busways on special 40 60 1 600 2 400 Urban population 750 000 CBD right of way employment 50 000 1 85 million m CBD floor Space congestion in corridor save buses 0 6 min km 1 min mi or more Busways within 40 60 1 600 2 400 Freeways in corridor experience freeway right of way peak hour congestion save buses 0 6 min km 1 min mi or more Busways on railroad 40 60 1 600 2 400 Potentially not well located in right of way relation to service area Stations required Freeway bus lanes 2 400 3 600 Applicable upstream from lane normal flow drop Bus passenger time savings should exceed other road user delays Normally achieved by adding a lane Save buses 0 6 min km 1 min mi or more Freeway bus lanes 40 60 1 600 2 400 Freeways with six or more lanes contraflow Imbalance in traffic volumes permits freeway LOS D in off peak travel direction Save buses 0 6 min km 1 min mi or more Bus lane bypasses 20 30 800 1 200 Adequate res
87. ity of Service Manual Exclusive arterial bus lane vehicle capacity Several bus stops may have to be tested to determine the critical bus stop as either dwell times or right turning volume may control Vehicle Capacity The adjustment factors for skip stop operations and right turn impacts define the following equations for estimating exclusive arterial street bus lane vehicle capacity non skip stop operation B B B Naf Equation 2 12 skip stop operation B f B B B Equation 2 13 where B bus lane vehicle capacity buses h By bus loading area vehicle capacity at the critical bus stop buses h Na number of effective loading areas at the critical bus stop capacity adjustment factor for right turns at the critical bus stop fi capacity adjustment factor for skip stop operations and B B vehicle capacities of each set of routes at their respective critical bus stops that use the same alternating skip stop pattern buses h The capacities B B etc used in Equation 2 13 are calculated separately for each set of routes using Equation 2 12 When determining the critical stop s several bus stops may have to be tested to determine which one controls the bus lane s vehicle capacity as one stop may have high dwell times but another may have severe right turning traffic interferences Because of the large number of factors involved it is not possible to develop summary tables of
88. just the passenger boarding and alighting times for special conditions Multiply the base boarding and or alighting times as appropriate by the following factors if the corresponding condition occurs e Heavy two way flow through a single door 1 2 e Double stream door 0 6 amp R 9 e Low floor bus 0 85 Step 5 Calculate the dwell time The dwell time is the time required to serve passengers at the busiest door plus the time required to open and close the doors A value of 2 to 5 seconds for door opening and closing is reasonable for normal operations The number of boarding and alighting passengers per bus through the busiest door during the peak within the peak typically 15 minutes P and P are determined by the proportions of boarding and alighting passengers per bus during the peak period t P t tP t t Equation 2 3 where ta dwell time s P alight ng passengers per bus through the busiest door during the peak 15 minutes p be passenger alighting time s p P boarding passengers per bus through the busiest door during the peak 15 minutes p tp passenger boarding time s p and bee door opening and closing time s Impact of Wheelchair Accessibility on Dwell Time All new transit buses in the U S are equipped with wheelchair lifts or ramps When a lift is in use the door is blocked from use by other passengers Typical wheelchair lift cycle times are 60 to 200 secon
89. latively independent of passenger service times and it is not possible to collect statistically useful data To determine passenger service times for use in evaluating the differences between systems such as single and dual stream doors high and low floor buses or alternate fare collection systems data collection should be done only at high volume stops These stops are typically downtown or at major transfer points The data collection effort will require one or two persons depending on the volume of passengers Following are steps that may be used to collect field data for estimating passenger service times An example of a data collection sheet is shown in Exhibit 2 64 From a position at the transit stop under study record the identification number and run number for each arriving vehicle 2 Record the time that the vehicle comes to a complete stop 3 Record the time that the doors have fully opened 4 Count and record the number of passengers alighting and the number of passengers boarding 5 Record the time that the major passenger flows end Note This is somewhat subjective but essential to correlate flows per unit of time The time for stragglers to board or exit should not be included 6 When passenger flows stop count the number of passengers remaining on board Note If the seating capacity of the transit vehicle is known the number of passengers on board may be estimated by counting the number of vacant seats
90. le Scheel and Foote found that bus start up times range from 2 to 5 seconds The time for a bus to travel its own length after stopping is approximately 5 to 10 seconds Door opening and closing time is incorporated into the dwell time rather than the clearance time Part 2 BUS TRANSIT CAPACITY Page 2 17 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Clearance time is the sum of start up and exiting time and re entry delay Exhibit 2 14 applies only to off line stops where buses must yield to other traffic when re entering a street and only when the stop is located away from the influence of a queue from a signalized intersection Re entry delay can be reduced or eliminated by using on line stops queue jumps at signals or laws requiring traffic to yield to buses The coefficient of variation of dwell times is the standard deviation of dwell times divided by the mean dwell time One tail normal variate Za Part 2 BUS TRANSIT CAPACITY depending on acceleration and traffic conditions TCRP Report 26 recommends a range of 10 15 seconds for clearance time Start up and exiting time may be assumed to be 10 seconds Re entry delay can be measured in the field or at locations where buses re enter a traffic stream may be estimated from Exhibit 2 14 based on traffic volumes in the adjacent travel lane If buses must wait for a queue from a signal to clear before they can re enter
91. lizing the added capacity provided by skip stop operations 1 Ka N 1 E N Equation 2 10 where K adjustment factor for the ability to fully utilize the bus stops in a skip stop operation 0 50 for random arrivals 0 75 for typical arrivals and 1 00 for platooned arrivals a adjacent lane impedance factor from Equation 2 11 and N number of alternating skip stops in sequence Part 2 BUS TRANSIT CAPACITY Page 2 48 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual 3 a i 038 c where v traffic volumes in the adjacent lane veh h and c capacity of the adjacent lane veh h Adjacent lane impedance factor Equation 2 11 These values result in added capacity with skip stops even when the adjacent lane is fully utilized by passenger vehicles since non stopping buses have zero dwell time at the stop When there is no spreading of stops there is no increase in capacity rendered by the adjacent lane Exhibit 2 49 gives representative values for the capacity adjustment factor fi for various types of bus lanes and stopping patterns As indicated previously these factors are applied to the sum of the capacities in the sequence of bus stops Thus they reflect the actual dwell times at each stop Exhibit 2 50 gives factors for a Type 2 bus lane with two block alternating stops In general the traffic impacts of the adjacent lane only become significant
92. lly no passing lane availability the buses will progress as if they were stopping at each stop with a zero dwell time at the intermediate stops When partial use of the adjacent lane is possible the bus speed will be Part 2 BUS TRANSIT CAPACITY Page 2 55 An alternative table using U S customary units appears in Appendix B Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual somewhere in between Skip stop speed adjustment Equation 2 17 expresses the speed adjustment factor for skip stop operation f as a factor fs function of both the traffic in the adjacent lane and the buses in the curb lane where d Vp Cp Exhibit 2 54 R29 yos A Bl UI di Ac V6 Equation 2 17 skip stop speed adjustment factor distance for one block stop pattern m or ft distance for multiple block stop pattern m or ft volume in adjacent lane veh h vehicular capacity of adjacent lane veh h bus volume in bus lane buses h and capacity of single bus lane buses h illustrates the effects of increasing bus v c ratio and general traffic v c ratio in the adjacent lane on the skip stop speed adjustment factor The exhibit assumes a two block skip stop pattern It can be seen that until the volume of the adjacent lane becomes more than about 5046 of the bus lane capacity the effect on bus speeds is minimal regardless of the bus lane v c ratio At higher v c ratios
93. low created at Could result in traffic queued into signalized intersections intersection when a bus stops in the travel lane Near Side e Minimizes interferences when Increases conflicts with right turning traffic is heavy on the far side of vehicles the intersection May result in stopped buses Allows passengers to access obscuring curbside traffic control buses closest to crosswalk devices and crossing pedestrians e Intersection width available for e May cause sight distance to be bus to pull away from the curb obscured for side street vehicles Eliminates potential for double stopped to the right of the bus stopping Increases sight distance problems for e Allows passengers to board and crossing pedestrians alight while bus stopped for red light Allows driver to look for oncoming traffic including other buses with potential passengers Mid Block e Minimizes sight distance Requires additional distance for no problems for vehicles and parking restrictions pedestrians Encourages passengers to cross May result in passenger waiting street mid block jaywalking areas experiencing less Increases walking distance for pedestrian congestion passengers crossing at intersections As mentioned previously the vehicle capacity of a bus stop depends primarily on the following two elements 1 the vehicle capacity of the individual loading areas that comprise the bus stop and 2 the number of
94. ly low that the added three seconds of delay to peak direction traffic during a queue jump should not cause cycle failures i e all queued peak direction traffic will clear the intersection on the next green signal Outline of Solution All of the input parameters are known Because the queue jump only takes green time away from through traffic in one direction it is not necessary to calculate delays for all movements Rather the average delay for peak direction automobile traffic is 3 seconds longer for those cycles when the queue jump is used The added delay to persons in automobiles during the queue jump cycles will be compared to the delay savings experienced by persons in peak direction buses All other persons in all other vehicles at the intersection experience no net change in person delay Steps 1 Calculate the delay savings to persons on peak direction buses At 18 s 6 bus h 40 p bus At 4320 person seconds At 72 person minute decrease 2 The average number of peak At 3 SY 6 cycle h 40 veh cycle 1 2 p veh direction automobiles traveling r through the intersection during a At 864 person seconds cycle in which a queue jump occurs At 15 person minute increase is 1600 40 or about 40 veh cycle Calculate the added delay to the occupants of these vehicles The Results The proposed queue jump will decrease person delay by approximately 57 person minutes during the peak hour The proposed queu
95. mand responsive service Unlike the other categories which address the capacity of facilities demand responsive capacity depends mostly on operating factors including the number of vehicles available the size of the service area and the amount of time during which service is offered See Exhibit 2 5 Exhibit 2 5 Typical Demand Response Vehicle Part 2 BUS TRANSIT CAPACITY Page 2 4 Chapter 1 8Bus Capacity Basics Transit Capacity and Quality of Service Manual FACTORS INFLUENCING BUS CAPACITY This section presents the primary factors that determine bus vehicle and person capacity These concepts will be used throughout the remainder of Part 2 Although many of the individual factors influencing vehicle capacity are different than those influencing person capacity this section will show that there are strong connections between vehicle and person capacity as well as between capacity in general and the concept of quality of service introduced in Part 5 Exhibit 2 6 illustrates the two dimensional nature of urban bus capacity It can be Relationship of person and seen that it is possible to operate many buses each carrying few passengers From a vehicle capacity highway capacity perspective the number of vehicles could be at or near capacity even if they run nearly empty Alternatively few vehicles could operate each overcrowded This represents a poor quality of service from the passenger perspective and long waiting times would fu
96. may have most of its passengers board in a suburb and disembark in the CBD In this situation the number of passengers carried at the maximum load point will be close to the total number of boarding passengers For a local bus with a variety of potential passenger trip generators along the length of the route the number of persons carried over the length of the route will be significantly greater than the express bus although both bus passenger loads at their respective maximum load points may be quite similar Part 2 BUS TRANSIT CAPACITY Page 2 1 Bus capacity is complex incorporating a number of factors Passenger service times at major bus stops and the number of vehicles operated usually determine bus route and lane person capacity Organization of Part 2 Exhibits also appearing in Appendix B are indicated by a marginal note such as this Vehicle vs person capacity As the length of time that passengers remain on a bus affects how many passengers may be carried over the length of a route person capacity is often measured at a route s maximum load point rather than measured for the route as a whole Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Buses generally form a small percentage of the total vehicular volume on a roadway but have the ability to carry most of the people traveling on a roadway Exhibit 2 1 illustrates the relationship between vehicle and person
97. ments presented in this chapter Part 2 BUS TRANSIT CAPACITY Page 2 37 The net change in person delay is an important factor to consider before implementing transit priority measures Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Exhibit 2 39 Bus Preferential Treatments Comparison R3 Treatment Advantages Disadvantages Signal Reduces control delay Priority e Improves reliability Reduces delay due to queues e Reduces delay from queues at e ramp meters or other locations Risks interrupting coordinated traffic signal operation Risks lowering intersection LOS if intersection is close to capacity Requires on going inter jurisdiction coordination Buses on the cross street may experience added delay greater than the time saved by the favored routes Bus lane must be available and longer than the back of queue Right lane must be available and longer moving left lane Parking Restrictions Increases bus speed by removing delays caused by Increases street capacity and reduces traffic delays Jump at signals than the back of queue e Buses can leap frog stopped e Special transit signal required traffic e Reduces green time available to other intersection traffic Bus drivers must be alert for the short period of priority green time Curb Reduces delay due to merging e Requires at least two travel lanes in Extensions back in
98. n conflicts Exhibit 2 29 and Exhibit 2 30 illustrate the use of curb extensions Exhibit 2 29 Curb Extension Concept Before Bus pulls to curb at bus stop must wait for gap in traffic to proceed After Curb extended into parking lane bus stops in travel lane more curbside parking available Exhibit 2 30 Curb Extension Example Vienna Austria Part 2 BUS TRANSIT CAPACITY Page 2 31 Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual Boarding Islands Where significant parking activity stopped delivery vehicles heavy right turning traffic volumes and other interferences slow traffic in the right lane of a street with multiple lanes in the same direction buses may be able to travel faster in the lane to the left Boarding islands allow bus stops to be located between travel lanes so that buses can use a faster lane without having to merge into the right lane before every stop Pedestrian safety issues must be addressed when considering the use of boarding islands Exhibit 2 31 and Exhibit 2 32 illustrate the concept and application of this treatment Exhibit 2 31 Boarding Island Concept Before Traffic congestion in curb lane due to parking and turning maneuvers After Bus travels in faster lane passengers load and unload at boarding island Exhibit 2
99. n from the green time for the peak direction of travel Y Lane configurations and traffic volumes are given in the figure below The queue jump operates on the eastbound direction on Main Street o o N 100 m BUS STOP Y The traffic signal cycle length is 90 seconds Protected left turn phasing is provided on Main Street and permitted left turn phasing is provided on Elm Street The peak hour factor is 0 94 Buses operate at 10 minute headways on Main Street and at 30 minute headways on Elm Street Y Average passenger vehicle occupancy is 1 2 average bus occupancy on Main Street is 40 in the peak direction and 20 in the off peak direction and average bus occupancy on Elm Street is 25 in the peak direction and 10 in the off peak direction XS Part 2 BUS TRANSIT CAPACITY Page 2 87 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Comments Y Busre entry delay cannot be calculated from Exhibit 2 14 in this case because the re entry delay is caused by waiting for a queue to clear at a signalized intersection rather than waiting for a gap in a traffic stream of randomly arriving vehicles Field measurements indicate that it takes 18 seconds on average for the queue to clear before buses are able to re enter the street The proposed queue jump would eliminate this delay Y A capacity analysis using the Highway Capacity Manual finds that the intersection s volume to capacity ratio is sufficient
100. nce Suggested service volumes are given in Exhibit 2 21 This table gives representative service volumes for downtown streets and arterial streets leading to the city center for each level of service Where stops are not heavily patronized as along outlying arterial streets volumes could be increased by about 25 percent Part 2 BUS TRANSIT CAPACITY Page 2 23 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual These service volumes may be used for planning purposes More precise values for operations and design purposes should be computed from the capacity relationships and procedures presented later in Part 2 The values for forced flow conditions should not be used for planning or design They are merely given for comparative purposes Exhibit 2 21 Suggested Bus Flow Service Volumes for Planning Purposes Flow Rates For Exclusive or Near Exclusive Lane RES Service Volume Average Description bus lane h bus lane h l ARTERIAL STREETS Free Flow 25 or less 15 Stable Flow Unconstrained 26 to 45 35 Stable Flow Interference 46 to 75 60 Stable Flow Some Platooning 76 to 105 90 Unstable Flow Queuing 106 to 135 120 Forced Flow Poor Operation over 135 150 l CBD STREETS Free Flow 20 or less 15 Stable Flow Unconstrained 21 to 40 30 Stable Flow Interference 41 to 60 50 Stable Flow Some Platooning 61 to 80 70 Unstable Flow Que
101. nce by mode between the two scenarios will be calculated and from this the net change in person trip times will be calculated Steps a Determine Transit Travel Times 1 Calculate the critical bus stop capacity under the exclusive bus lane scenario using Equation 2 5 With right turns prohibited the critical stop is the one with the highest dwell time stop 3 2 Calculate the skip stop capacity adjustment factor from Equation 2 10 Half of the automobiles are assumed to use the lane adjacent to the exclusive bus lane 3 Calculate the bus vehicle capacity of the exclusive bus lane using Equation 2 13 4 Identify the base bus speed using Exhibit 2 53 Because the capacity analysis accounts for right turn delays or the lack of delays in this case the dual contraflow column is used The average dwell time for the four stops is 31 25 seconds so interpolate between the 30 second and 40 second values Part 2 BUS TRANSIT CAPACITY B B N 3 600 g C uo a OG EZ 6E nae 3 600 0 45 104 0 45 40 4 01 44 0 60 40 B 26 bus h B 26 1 85 B 48 bus h 1 Ka N 1 dd N Ss 3 a i 038 c 3 a ELE 747 a 0 59 1 0 50 0 59 2 1 fi 2 f 9 65 B f B B 4 B B 0 65 48 48 B 62 bus h V 212 7 km h Page 2 85 Chapter 8 Example Problems Part 2 BUS TRANSIT CAPACITY Transit Capacity and Quality of Service Manual 5 Calculate the skip s
102. nd few to one types of service vehicles are usually assigned to geographical areas with the number of vehicles assigned to each geographic area depending on the number of passengers from that area that need to be accommodated at a given time Every passenger should be provided with a seat in demand responsive service For other kinds of service particularly many to many services such as dial a ride the number of vehicles required is dependent on passenger demand and the size of the service area to be covered Some larger dial a ride systems use a hub and spoke system where each vehicle picks up and drops off passengers in a designated geographic area during a specified period of time then returns to a central location to meet the other vehicles to transfer passengers This arrangement provides greater person capacity per vehicle but may not be feasible for systems serving the elderly and persons with disabilities as these customers should be required to board and alight as little as possible To date no national studies have been performed on demand responsive person capacity particularly for dial a ride types of service so this chapter does not provide calculation procedures for estimating demand responsive capacity However the following general statement about capacity can be made a demand responsive vehicle s person capacity is inversely related to the size of its service area and also is inversely related to the number of potential origi
103. nd re entering freeways Freeway stops should be located away from the main travel lanes and adequate acceleration and deceleration lanes should be provided To be successful attractive well designed pedestrian access to the stop is essential The bus stop location influences vehicle capacity particularly when passenger vehicles are allowed to make right turns from the curb lane as is the case in most situations except for certain kinds of exclusive bus lanes Far side stops have the least effect on capacity when buses are able to use an adjacent lane to avoid right turn queues followed by mid block stops and near side stops However vehicle capacity is not the only factor which must be considered when selecting a bus stop location Potential conflicts with other vehicles operating on the street transfer opportunities the distances passengers must walk to and from the bus stop locations of passenger generators signal timing driveway locations physical obstructions and the potential for implementing transit preferential measures must also be considered For example near side stops are preferable when curb parking is allowed since there is more space for buses to re enter the moving traffic lane They are also desirable at intersections where buses make a right turn and at intersections with one way streets moving from right to left Where buses operate in the curb lane and or right turning traffic is heavy far side stops are pr
104. nes A single lane exclusive bus lane located along the right curb Separate values are shown for CBD central city and suburban areas representing different assumed delays per kilometer mile due to signal and traffic delays If the capacity analysis included capacity reductions due to right turn delays the dual contraflow lanes column should be used instead e Dual Contraflow Bus Lanes Either 1 two exclusive bus lanes located adjacent to the right curb or 2 a contraflow lane that operates opposite the normal traffic flow on one way streets without vehicle or turning conflicts The speeds shown in this column include control delays only Right Turn Delays Right turns from a bus lane can adversely affect bus speeds especially where both right turns and pedestrian volumes are heavy These impacts are greatest for near side stops where buses and turning traffic compete for the same roadway space These impacts are included in a general way in Exhibit 2 53 for single normal flow bus lanes These values may be used where buses stop every block and where conflicting right turn impacts are generally light However both the bus bus interference and skip stop speed adjustment factors introduced below include a vehicle capacity component and thus may already reflect the impacts of right turns Therefore the dual flow column should be used for the basic speed estimate when the vehicle capacity adjustment factors have been applied to the calcul
105. ng distance services may cause the operator to set the allowed loading at levels lower than what riders might tolerate The impacts of all three of these perspectives on transit capacity are addressed in this section The quality of service impacts of passenger loading are addressed in Part 5 of this manual Guidelines The passenger load is simply the number of passengers on a single transit vehicle Much work uses the occupancy of the vehicle relative to the number of seats expressed as a load factor A factor of 1 0 means that all of the seats are occupied The importance of vehicle loading varies by the type of service In general bus transit provides load factors below 1 0 for long distance commute trips and high speed mixed traffic operations Inner city service can approach a load factor of 2 0 but more typically 1 5 while other services are in between Typical bus vehicle types dimensions and passenger capacities are given in Exhibit 2 23 Exhibit 2 23 Characteristics of Bus Transit Vehicles United States and Canada Length Width Typical Capacity Bus Type m m Seats Small Bus Minibus 5 6 9 1 2 0 2 4 8 30 0 10 8 40 Transit Bus 10 7 2 4 2 6 30 35 20 30 50 60 12 2 35 50 30 40 65 75 low floor 12 2 24 30 40 25 40 55 70 articulated 183 2426 65 55 120 NOTE In any transit vehicle the total passenger capacity can be increased by removing seats and by making more standing room
106. nger buses This is accomplished through a combination of fare free service few seats passenger travel distances are short low floor buses and three double stream doors on the buses Dwell Time Variability Not all buses stop for the same amount of time at a stop depending on fluctuations in passenger demand between buses and between routes The effect of variability in bus dwell times on bus capacity is reflected by the coefficient of variation of dwell times which is the standard deviation of dwell time observations divided by the mean dwell time Dwell time variability is influenced by the same factors that influence dwell time Denver s Regional Transit District RTD planned to switch to 128 passenger buses in 1999 to accommodate growing passenger demand for this service Part 2 BUS TRANSIT CAPACITY Page 2 8 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Clearance Time Once a bus closes its doors and prepares to depart a stop there is a period of time known as the clearance time during which the loading area is not available for use by the following bus Part of this time is fixed consisting of the time for a bus to start up and travel its own length clearing the stop For on line stops though this is the only component of clearance time For off line stops however there is another component to clearance time the time required for a suitable gap in traffic to allow the bus to re enter
107. ns and destinations it must serve The best method for estimating demand responsive person capacity is to identify a well used demand responsive system serving an area similar to one for which service is contemplated and to identify the number of passengers per hour or per day that system is capable of serving A demand responsive vehicle s person capacity is inversely related to the vehicle s service area and the number of potential origins and destinations it must Serve Part 2 BUS TRANSIT CAPACITY Page 2 67 Chapter 6 Demand Responsive Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 68 Chapter 6 Demand Responsive Transit Capacity and Quality of Service Manual 7 REFERENCES 1 Bullard Diane L and Lisa G Nungesser Texas Public Transit Reference Manual Technical Report 1082 1F Texas State Department of Highway and Public Transportation Austin TX 1985 2 Cervero Robert Paratransit in America Redefining Mass Transportation Praeger Publishers Westport CT 1997 3 City of Portland Transit Preferential Streets Program Sourcebook Guidelines for Implementing Transit Preferential Streets Measures Office of Transportation Portland OR 1997 4 Cuntill M A and P F Watts Bus Boarding and Alighting Times Report LR 521 Great Britain Transport and Road Research Laboratory Crowthorne England 1973 5 Edwards Jr John D editor
108. ocedure Transit Capacity and Quality of Service Manual 5 Record the time that the major passenger flows end 6 When passenger flows stop count the number of passengers remaining on board Note If the seating capacity of the transit vehicle is known the number of passengers on board may be estimated by counting the number of vacant seats or the number of standees 7 Record time when doors have fully closed 8 Record time when vehicle starts to move Note Waits at timepoints or at signalized intersections where dwell is extended for cycle should be noted but not included in the dwell time Delays at bus stops when a driver is responding to a passenger information request are everyday events and should be included in the calculation of dwell time Time lost dealing with fare disputes lost property or other events should not be included 9 Note any special circumstances In particular any wheelchair movement times should be noted Whether this is included in the mean dwell time depends on the system Dwell times due to infrequent wheelchair movements are often not built into the schedule but rely on the recovery time allowance at the end of each run The observer must use judgment in certain cases At near side stops before signalized intersections the driver may wait with doors open as a courtesy to any late arriving passengers The doors will be closed prior to a green light This additional waiting time should not be counted as
109. onventional rigid body 1 Front 2 0 2 6 to 3 0 1 7 to 2 0 1 Rear 2 0 NA 1 7 to 2 0 2 Front 1 2 fies ecu 1 0 to 1 2 2 Rear 1 2 NA 1 0 de 2 2 Front Rear 1 2 NA 4 Front Rear 0 7 NA D Articulated 3 Front Rear 0 9 NA 0 8 Center 2 Rear 1 29 NA m 2 Front Center 0 6 6 Front Rear 0 5 NA 0 4 1 Center Special Single Unit 6 3 Double 0 5 NA 0 4 Doors NA data not available a Typical interval in seconds between successive boarding and alighting passengers Does not allow for clearance times between successive buses or dead time at stop gt Also applies to pay on leave or free transfer situation Not applicable with rear door boarding Higher end of range is for exact fare One each Two double doors each position Less use of separated doors for simultaneous loading and unloading 9 Double door rear loading with single exits typical European design Provides one way flow within vehicle reducing internal congestion Desirable for line haul especially if two person operation is feasible May not be best configuration for busway operation Examples Denver 16 Street Mall shuttle airport buses used to shuttle passengers to planes Typically low floor buses with few seats serving short high volume passenger trips Part 2 BUS TRANSIT CAPACITY Page 2 16 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Step 4 Ad
110. or the number of standees 7 Record time when doors have fully closed 8 Record time when vehicle starts to move Note Leave time should exclude Part 2 BUS TRANSIT CAPACITY Page 2 89 Appendix A Dwell Time Data Collection Procedure Transit Capacity and Quality of Service Manual waits at timepoints or at signalized intersections where dwell is extended for cycle 9 Note any special circumstances In particular any wheelchair movement times should be noted Passenger service time for each arrival is computed by taking the difference between the time that the door opens and the main flow stops Service time per passenger is computed by dividing the number of passengers boarding by the total service time Exhibit 2 64 Sample Passenger Service Time Data Collection Sheet Passenger Service Time Data Sheet Date Time Route Location Direction Bus Arrival Doors Main Doors Bus Passengers Passengers Psgrs Notes Run Time Open Flow Closed Leaves Boarding Alighting Departing Number Stops Front Rear Front Rear _On Board LI L j DWELL TIMES The procedure for determining dwell times is similar to that for estimating passenger service times except dwell times are best determined with ride checks With ride checks the observer rides the transit vehicle over the entire route for several runs at different times of day A single observer can usually monito
111. or when exclusive bus lanes are located in the center of the street a bus stop may be located on a boarding island within the street rather than curbside When boarding islands are used pedestrian safety and ADA accessibility issues should be carefully considered Exhibit 2 9 depicts typical on street bus stop locations The time required for a bus to start up and travel its own length is fixed re entry delay for off line stops is dependent on traffic volumes in the curb lane Bus stop design for bus terminals must consider passenger factors and take into account longer loading area occupancies by buses The three typical on street bus stop locations are near side far side and mid block Part 2 BUS TRANSIT CAPACITY Page 2 9 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Freeway bus stops Far side stops have the most beneficial effect on bus stop vehicle capacity but other factors must also be considered when siting bus stops Exhibit 2 9 On Street Bus Stop Locations 9 Near Side Mid Block Special bus stops are sometimes located along freeway rights of way usually at interchanges or on parallel frontage roads Examples include stops in Marin County California and in Seattle where they are known as flyer stops These stops are used to reduce travel time for buses by eliminating delays associated with exiting a
112. ose the doors e Dwell Time Variability The variations in dwell time among different buses using the same loading area affect capacity The greater the variation the lower the vehicle capacity e Clearance Time Clearance time is the average time between one bus leaving a stop and a following bus being able to enter the stop Each of these elements is addressed in more detail below Dwell Time Just as dwell times are key to determining vehicle capacity passenger demand volumes and passenger service times are key to determining dwell time Dwell times may be governed by boarding demand e g in the p m peak period when relatively empty buses arrive at a heavily used stop by alighting demand e g in the a m peak period at the same location or by total interchanging passenger demand e g at a major transfer point on the system In all cases dwell time is proportional to the boarding and or alighting volumes times the service time per passenger Dwell time can also influence a bus operator s bottom line if average bus speeds can be increased by reducing dwell time fewer vehicles may be required to provide the same service frequency on a route if the cumulative change in dwell time exceeds the existing route headway As shown in Exhibit 2 7 there are five main factors that influence dwell time Two of these relate to passenger demand while the other three relate to passenger service times e Passenger Demand and Loading The num
113. our factor Part 2 BUS TRANSIT CAPACITY Page 2 61 In mixed traffic situations on line stops may provide greater capacity than off line stops depending on traffic volumes and the number of loading areas provided Chapter 5 Mixed Traffic Transit Capacity and Quality of Service Manual CALCULATING SPEED As always the best way to determine bus travel speeds is to measure them directly If this is not possible for example when planning future service speeds can be estimated by 1 driving the route making an average number of stops with simulated dwells making two or three runs during peak and off peak times 2 scheduling buses based on similar routes and adjusting running times as needed based on the operating experience or 3 using the analytical method described below to estimate speeds The speeds of buses operating in mixed traffic are influenced by bus stop spacing dwell times delays due to traffic signals and interferences from other traffic operating in the lane The method used to estimate bus speeds in mixed traffic is similar to that used for exclusive arterial street bus lanes as indicated by Equation 2 20 The difference is that Exhibit 2 60 should be used for determining the base bus speed which takes into account the added delay caused by mixed traffic operating in the curb lane V zVof f Equation 2 20 where V travel speed km h or mph Vo base bus speed in mixed traffic km h or mph from
114. owever since this peak demand is not sustained over the entire hour and since not every bus will experience the same peak loadings actual person capacity during the hour will be less than that calculated using peak within the peak demand volumes The average passenger trip length affects how many passengers may board a bus as it travels its route If trip lengths tend to be long passengers board near the start of the route and alight near the end of the route buses on that route will not board as many passengers as a route where passengers board and alight at many locations However the total number of passengers on board buses on each route at their respective maximum load points may be quite similar The distribution of boarding passengers among bus stops affects the dwell time at each stop If passenger boardings are concentrated at one stop the vehicle capacity of a bus lane will be lower since that stop s dwell time will control the vehicle capacity and in turn the person capacity of the entire lane Vehicle capacity and person capacity at the maximum load point is greater when passenger boarding volumes and thus dwell times are evenly distributed among stops Vehicle Capacity The vehicle capacity of various facilities used by buses loading areas bus stops and bus lanes set an upper limit to the number of passengers that may use a bus stop or may be carried past a bus route s or bus lane s maximum load point Th
115. passengers at intermediate stops and so induce delay and reduce vehicle capacity Although crush loading represents the theoretically offered capacity it cannot be sustained on every bus for any given period and it exceeds the maximum utilized capacity Therefore crush loads should not be used for transit capacity calculations Note however that when maximum schedule loads are used some buses will experience crush loading due to the peaking characteristics of passenger demand Design guidelines for seats and passenger areas in transit vehicles are based on human factors Part 5 addresses the quality of service aspects of passenger loading For buses comfortable loading for design should provide at least 0 50 m passenger 5 4 ft p and maximum schedule loads should provide a minimum of 0 40 m7 p 4 3 ft p where relatively short trips allow standees 7 The comfortable loading figure provides a reasonable balance between operating economy and passenger comfort and is consistent with the value suggested by Pushkarev and Zupan for a realistic passenger capacity for rapid transit lines However high speed express bus service should not allow standees hence their scheduling should be guided by the number of seats provided Skip Stop Operation When buses stop at every curbside bus stop in an on line loading area arrangement using the adjacent lane only becomes necessary for passing obstructions in the curbside lane The ability to s
116. pread out stops alternating route stop patterns along an arterial street can substantially improve bus speeds and capacities Many large transit systems have instituted two or three block stop patterns for bus stops along arterial streets This block skipping pattern allows for a faster trip through the section and reduces the number of buses stopping at each bus stop Exhibit 2 24 illustrates the skip stop pattern used by Tri Met in Portland Oregon on its Fifth and Sixth Avenue Transit Mall in 1997 Each street uses a repeating pattern of three or four bus stops Each bus stop contains two loading areas All routes headed for a particular portion of the metropolitan area use a particular set of stops which are designated by a colored symbol for example a brown beaver on bus stop signs bus schedules and maps As shown in Exhibit 2 24 other bus stop signing systems can also be used such as Denver s X Y Z system These alternate block stopping patterns enable the bus lane capacity to nearly equal the sum of the capacities of the stops involved Thus an arterial with an alternate two block stopping pattern would ideally have a capacity equal to the sum of the two stops assuming unimpeded use of the adjacent lane In reality this may not always be possible because of the irregularity of bus arrivals and traffic control delays To effectively double the capacity of a segment with a 3 bus loading area capacity at each stop by institut
117. press buses routes ending in X stop every four blocks The number of buses using the orange deer stops decreased in the fall of 1998 following the opening of the Westside MAX light rail extension which replaced many of the routes using those stops Other systems for designating bus stops in a skip stop sequence are also possible such as Denver s X Y Z system pictured to the left Chapter 2 Operating Issues Transit Capacity and Quality of Service Manual ROADWAY OPERATIONS Much attention has been paid to expediting transit flow by providing various forms of priority treatment Such treatments are aimed at improving schedule adherence and reducing travel times and delays for transit users They may attract new riders increase transit capacity and or improve the transit quality of service Successful priority measures are usually characterized by e an intensively developed downtown area with limited street capacity and high all day parking costs a long term reliance on public transport highway capacity limitations on the approaches to downtown major water barriers that limit road access to the CBD and channel bus flows fast non stop bus runs for considerable distances bus priorities on approaches to or across water barriers special bus distribution within the CBD often off street terminals and active traffic management maintenance operations and enforcement programs Bus Preferential Trea
118. r 5 Mixed Traffic Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY Page 2 64 Chapter 5 Mixed Traffic INTRODUCTION Demand responsive services encompass a wide range of transportation services as shown in Exhibit 2 61 The differences among the types of services include the kinds of vehicles used and their passenger capacity the locations service is provided to and how service is provided 6 DEMAND RESPONSIVE Transit Capacity and Quality of Service Manual Exhibit 2 61 Characteristics of Different Demand Responsive Bus Systems Service Service Typical Primary Typical Degree of Types Configuration Passenger Markets Regulatory Regulatory I Loads L Jurisdiction Restriction I Commercial Services Shared Ride On demand Many to many 3 4 Downtown City High Taxis hail request airports train stations Dial a ride On demand Many to many 6 10 Elderly City State Low Specialized amp phone amp hail handicapped General request Airport On demand Few to one 6 10 Air travelers State Low to Shuttles phone amp hail airports moderate n request Jitneys Regular Fixed route loop 6 15 Employees City Moderate to Circulators route fixed one to one specialized high I stops Transit Regular Many to one 6 15 Employees City Moderate to Feeders
119. r both doorways on a 12 meter 40 foot bus While it is more difficult for a single observer to handle articulated buses that have three doorways it is possible with an experienced checker For light rail transit vehicles at least one observer per car will be required Automated equipment can also monitor dwell times possibly in conjunction with automatic passenger counting equipment Usually a given route will have similar equipment Where equipment types single door double doors rigid articulated high floor low floor are intermixed separate data sets should be obtained for each type of equipment Following are steps that may be used to collect the necessary field data to develop a procedure for estimating dwell time for buses or LRT A sample data collection sheet is shown in Exhibit 2 65 This sheet can be adapted to also record traffic and intersection delays Where passenger service times are not needed door open flow stop and door close columns can be omitted Following are steps that may be used to collect field data for estimating passenger service times 1 From a position on the transit vehicle record the stop number or name at each stop 2 Record the time that the vehicle comes to a complete stop 3 Record the time that the doors have fully opened 4 Count and record the number of passengers alighting and the number of passengers boarding Part 2 BUS TRANSIT CAPACITY Page 2 90 Appendix A Dwell Time Data Collection Pr
120. rivals are assumed Automobile volumes in the left two lanes are assumed to be evenly distributed Adjustment factor K for random arrivals from Equation 2 10 is 0 50 Outline of Solution As in Example Problems 2 and 3 all input parameters are known The critical A and B bus stops will determine the bus lane capacity The v c ratio of the adjacent lane will need to be calculated to determine how well buses can use that lane to skip stops The bus lane capacity will be the sum of the capacities of the A and B stop patterns times an adjustment factor for the effect of random bus arrivals and the impedance of other traffic in the adjacent lane Steps 1 Calculate the adjacent lane capacity At stop 1 v 1200 350 50 2 400 vph c vo 8 C fuy f c 1900 vph 0 45 0 971 0 90 c 747 vph 2 Calculate the adjacent lane At stop 1 impedance factor from Equation 2 3 Ih a 1 04 C 3 a 1 0 8 a T4 a 0 88 3 Calculate the skip stop adjustment 1 Ka N 1 factor from Equation 2 10 Lr VN MUN Fo k N 1 0 5 0 88 2 1 f 2 f 0 72 Part 2 BUS TRANSIT CAPACITY Page 2 81 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual 4 The A pattern bus lane capacity B f B B 4B from Example Problem 2 is 35 buses 7 per hour The B pattern is assumed B 0 72 35 35 to be the same Calculate the total B 50bus h bus vehicle capacity of the
121. rther detract from user convenience Finally the domain of peak period operations in large cities commonly involves a large number of vehicles each heavily loaded Exhibit 2 6 Relationship Between Person and Vehicle Capacity CRUSH LOAD MAXIMUM PEOPLE PER VEHICLE MAXIMUM DESIGN LOAD PEAK Level of Service Passenger area passenger YNOH H3d TANNVHO H3d S310IH3A WNNWIXYN A B C D E F Level of Service Bus vehicles hour Vehicle Capacity Vehicle capacity is commonly calculated for three locations e loading areas bus berths e bus stops and e bus lanes Each of these locations has one or more elements that determines its capacity and each of these elements has a number of factors that further influence capacity Exhibit 2 7 illustrates the key factors that affect vehicle capacity Part 2 BUS TRANSIT CAPACITY Page 2 5 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Vehicle capacity is commonly calculated at three locations loading areas bus berths bus stops and bus lanes The capacity of each of these locations is influenced by one or more elements middle column each of which in turn is influenced by a number of factors left column Part 2 BUS TRANSIT CAPACITY Exhibit 2 7 Bus Vehicle Capacity Factors Passenger Demand amp Loading Bus Stop Spacing Dwell Time Dwell Time Variability Fare Paymen
122. s are concentrated at the beginning of the signal green interval for bus movement on the arterial when queued groups of pedestrians step off of the curb By crossing or utilizing space in the bus lane to execute their turn right turning vehicles reduce the bus lane vehicle capacity by preempting a portion of the green time available to buses Thus bus lane vehicle capacity will be approached more quickly when right turns occur For bus volumes at less than half of the bus lane vehicle capacity there is generally little impact on the resulting speed of bus operations from a moderate volume of right turns unless pedestrian volumes are very heavy Procedures for estimating the capacity of right turns are given in the Highway Capacity Manual The effects of right turns on bus lane vehicle capacity can be estimated by multiplying the bus lane vehicle capacity without right turns by an adjustment factor The values of this adjustment factor f may be estimated from Equation 2 9 Capacity adjustment for the effects of right turning traffic Part 2 BUS TRANSIT CAPACITY Page 2 47 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Right turn adjustment factor Bus stop location factor Impedance factor us f rz Equation 2 9 where fe right turn adjustment factor fi bus stop location factor from Exhibit 2 48 v volume of right turns at specific intersection and Cr capa
123. s are discussed in Chapter 6 and mixed traffic situations are discussed in Chapter 7 BUS LANE TYPES The vehicle capacity procedures used in this chapter define three types of bus lanes The availability of the adjacent lane for buses to pass other buses right turn queues or other bus lane obstructions is the main difference among the three types of bus lanes Type 1 exclusive bus lanes have no use of the adjacent lane for example contraflow lane and physically channelized lanes Exhibit 2 45 depicts Type 1 exclusive bus lanes Type 2 exclusive bus lanes have partial use of the adjacent lane depending on the use of this lane by other traffic Right turns may or may not be prohibited Exhibit 2 46 shows examples of Type 2 exclusive bus lanes Type 3 exclusive bus lanes dual bus lanes have full use of the adjacent lane with only occasional use by authorized vehicles other than buses and right turns are prohibited Exhibit 2 47 illustrates Type 3 exclusive bus lanes Single bus lanes with off line stops and right turn prohibitions are also considered Type 3 bus lanes as buses have an unimpeded opportunity to pass stopped buses Exhibit 2 45 Type 1 Exclusive Bus Lane Examples Los Angeles Exclusive arterial street bus lanes are characterized by at least one lane exclusively for buses except possibly at intersections and interrupted flow Bus lane types described Part 2 BUS TRANSIT CAPACITY Page 2 45 Chapter 4 Exclusiv
124. s are more effective than linear loading areas when four or five loading areas are required Part 2 BUS TRANSIT CAPACITY Exhibit 2 16 Estimated Maximum Capacity of Loading Areas Buses h DwellTime s Dwell Time s g Cz05 g C 10 15 63 100 30 43 63 45 32 46 60 26 36 75 22 30 90 19 25 105 16 22 120 i 15 i 20 NOTE Assumes 15 second clearance time 25 queue probability and 60 coefficient of variation of dwell times Bus Stops As shown in Exhibit 2 17 increasing the number of loading areas at a linear bus stop has an ever decreasing effect on capacity as the number of loading areas increases doubling the number of loading areas at a linear bus stop does not double capacity When more than three loading areas are required sawtooth pull through or other non linear designs should be considered Exhibit 2 17 Efficiency of Multiple Linear Loading Areas at Bus Stops 19 R21 R23 On Line Loading Areas Off Line Loading Areas of Cumulative of Cumulative Loading Efficiency Effective Loading Efficiency Effective Loading Area 26 Areas Areas 1 100 1 00 2 85 1 85 3 60 2 60 4 20 3 25 5 5 3 75 NOTE On line values assume that buses do not overtake each other The off line loading area efficiency factors given in Exhibit 2 17 are based on experience at the Port Authority of New York and New Jersey s Midtown Bus Terminal The on line loading efficiency f
125. s determined from Exhibit 2 53 which includes the effects of stop spacing dwell times and traffic and control delays The base speed is then modified by adjustment factors accounting for skip stop operations and bus bus interferences These factors are described below Bus lane person capacity at the maximum load point is the bus lane vehicle capacity times the allowed passenger loading times the peak hour factor Bus speeds are best measured directly or estimated based on local conditions and operating experience Part 2 BUS TRANSIT CAPACITY Page 2 53 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Bus travel speed calculation Base bus speed Vo V V f f Equation 2 16 where V travel speed km h or mph Vo base bus speed km h or mph from Exhibit 2 53 or Appendix B skip stop operation adjustment factor from Equation 2 17 and fo bus bus interference adjustment factor from Exhibit 2 55 Base Bus Speeds Exhibit 2 53 provides estimates of base bus speeds on arterial street bus lanes Vo as a function of stop spacing average dwell time and typical traffic signal and right turn delays based on field measurements The exhibit provides data for each of the following situations e Without Traffic Delays An exclusive bus lane operating without either signal or traffic delays The only source of delay is dwell time at stops e Single Normal Flow Bus La
126. scheduled along a freeway will be constrained by the vehicle capacity of the off line bus stops along the HOV lane section or by the bus stops located after the end of the HOV lane For example the maximum number of buses using an exclusive bus lane in North America 735 buses per hour is achieved through an a m peak hour contraflow lane serving the Lincoln Tunnel in New York with no stops along the lane and with an 210 berth bus terminal to receive these and other buses Busways Exclusive busway vehicle and person capacity can be computed using appropriate assumptions regarding the type of bus used maximum allowable bus loading the distribution of ridership among CBD stops the peak hour factor and the type of loading area If the busway extends into the CBD for example the Seattle Bus Tunnel and has a limited number of stations in the downtown area the busway s passenger distribution characteristics will be similar to those of a subway or other rail line A reasonable design assumption is that 50 percent of the maximum load point volume is served at the heaviest CBD busway station assuming a minimum of three stops in the downtown area For comparison the Washington State Street subway station in Chicago accounts for about half of all boarding passengers at the three CBD stops on the State Street subway line Peak hour factors of 0 67 to 0 75 are reasonable for busways depending on the location and type of operation Illus
127. ssenger This time can be reduced by minimizing the number of bills and coins required to pay a fare encouraging the use of pre paid tickets tokens passes or smart cards using a proof of payment fare collection system or developing an enclosed monitored paid fare area at high volume stops In addition to eliminating the time required for each passenger to pay a fare on board the bus proof of payment fare collection systems also allow boarding passenger demand to be more evenly distributed between doors rather than being concentrated at the front door e Vehicle Types Low floor buses decrease passenger service time by eliminating the need to ascend and descend steps This is particularly true when a route is frequently used by the elderly persons with disabilities or persons with strollers or bulky carry on items e On Board Circulation Encouraging people to exit via the rear door s on buses with more than one door decreases passenger congestion at the front door and reduces passenger service times In certain locations dwell time can also be affected by the time to board and disembark passengers in wheelchairs and for bicyclists to load and unload bicycles onto a bus mounted bicycle rack Combinations of these factors can substantially reduce dwell times Denver s 16 Street Mall shuttle operation is able to maintain 75 second peak headways with scheduled 12 5 second dwell times despite high peak passenger loads on its 70 passe
128. ssere nene eene 2 37 Roadway Operations Summary esses 2 37 3 BUSWAYS AND FREEWAY HOV LANES eeeeeee reete eene tn sins tn sts tn sena 2 39 Wrnieitesto M 2 39 Calculating Vehicle Capacity essent 2 40 Freeway HOV Lanes nee ee teer dett ees 2 40 nav lS 2 40 Calculating Person Capacity tet ecu eR eet eevee ten 2 41 Calculating Speed ce eee cette eet e tered see 2 42 4 EXCLUSIVE ARTERIAL STREET BUS LANES eeeeeeeeeeee eret tn nnn 2 45 Introduction 5 5 ect ettet eere epe re pe eig ec beue veta 2 45 Bus Lane Types m 2 45 Calculating Vehicle Capacity eese enne eene 2 47 Effects Of Right T rns eren rrr Retire EEE E E 2 47 Skip Stop Adjustment Factor esee nennen nennen 2 48 Vehicle Capacity 3 dno Ege epe nete duet este terii ended 2 50 Bus Effects on Passenger Vehicle Capacity in an Adjacent Lane 2 52 Calculating Person Capacity enne pectet etre tetigi dre ns 2 53 Calculating Speed eot rer e Ret eed pe 2 53 Base Bus Speeds one oe EHE E E irte andes 2 54 Right Turn Delays Ra Riel eee RAS 2 54 Skip Stop Operations trece eerie cei ep Rp PER erheben 2 54 Bus Bus Interference eR Uc n n Ue nhe ttt RU reci bete 2 57 Part 2 BUS TRANSIT CAPACITY Page 2 i Contents Transit Capacity and Quality of Service Manual 5 MIXED TRAFFIC eeeeeeeee esee ee eene sets tn
129. t Method Vehicle Type amp Size On Board Circulation Loading Area Vehicle Capacity On Off Line Stops Traffic Clearance Volumes Time Traffic Laws Bus Queuing Failure Rate Bus Number of Bus Stop Volumes Loading Areas Vehicle Capacity Traffic Signal Timing Loading Area Design Bus Lane Type Skip Stop Operations Bus Operational Issues Bus Lane Vehicle Capacity Platooning Bus Stop Location Page 2 6 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual Loading Areas A loading area or bus berth is a space for buses to stop and board and discharge passengers Bus stops discussed below contain one or more loading areas The most common form of loading area is a linear bus stop along a street curb In this case loading areas can be provided in the travel lane on line where following buses may not pass the stopped bus or out of the travel lane off line where following buses may pass stopped vehicles Exhibit 2 8 depicts these two types of loading areas Exhibit 2 8 On Line and Off Line Loading Areas 9 On Line i i Off Line The main elements affecting loading area vehicle capacity are the following e Dwell Time Dwell time is the single most important factor affecting vehicle capacity It is the time required to serve passengers at the busiest door plus the time required to open and cl
130. t changes is the location factor f which is 0 5 for a Type 2 mixed traffic lane Summary table for all stops Stop Pm fr c v fm B B 1 0795 0843 859 440 058 33 35 2 0 588 0 828 519 340 0 67 29 36 3 0 417 0 838 525 240 0 77 26 37 4 ove ost 509 390 o62 45 52 The Results Part 2 BUS TRANSIT CAPACITY Bus lane vehicle capacity improves substantially as a result of using far side stops but is still below the value of 40 buses per hour that is required If only one stop was the constraint on capacity a right turn prohibition at that intersection might be considered but in this case three of the four stops have insufficient vehicle capacity Page 2 80 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Example Problem 6 The Situation The CBD street from Example Problems 4 and 5 The transit Mixed traffic lane bus vehicle operator would next like to try a skip stop operation to improve capacity with skip stop operation capacity The Question How will the street operate under this scenario The Facts Same assumptions as Example Problem 5 Half of the buses will use A pattern stops which are the same ones used in Problem 4 The other half will use B pattern stops in the alternate blocks For this example the critical B stop has the same characteristics as the critical A stop Comments Random bus ar
131. tential effect on speed and capacity than does implementing skip stop operation However if it is possible only to lengthen the critical stop from Example Problem 2 skip stop operations may have a greater effect depending on the vehicle capacity of the critical one berth bus stop Part 2 BUS TRANSIT CAPACITY Page 2 77 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual Mixed traffic lane bus vehicle capacity with near side stops Part 2 BUS TRANSIT CAPACITY Example Problem 4 The Situation A transit operator wants to consolidate its outbound downtown bus routes which currently use several streets onto a single three lane one way street The Question How will the street operate with the added buses The Facts Y g C 0 45 Y 40 buses per hour will use the street Y 1200 automobiles per hour will also use the street Y Toreduce walking distances for passengers from the shelter to the bus door and thus minimize dwell times the transit operator desires to limit the number of loading areas to two per stop Y Nearsside on line stops located every two blocks Y No on street parking no grades 3 6 m 12 ft travel lanes Y Dwell times curb lane auto right turn volumes curb lane auto through volumes and conflicting pedestrian movements as follows Right Turn Through Auto Conflicting Stop Dwell Time s Volume Volume Ped Volume 1 30 350 50 10
132. the street Exhibit 2 14 should not be used instead re entry delay should be estimated using the average queue length in vehicles the saturation flow rate and the start up lost time Exhibit 2 14 Average Bus Re Entry Delay into Adjacent Traffic Stream Random Vehicle Arrivals Adjacent Lane Average Re Entry Delay 4 Mixed Traffic Volume veh s l 100 0 200 1 300 2 400 3 500 4 600 5 700 7 800 9 900 11 1 000 14 Computed using 1997 HCM unsignalized intersection methodology minor street right turn at a stop sign assuming a critical gap of 7 seconds and random vehicle arrivals Delay based on 12 buses stopping per hour SOURCE Some states in the U S have passed laws requiring other traffic to yield to transit vehicles that are signaling to exit a stop In these locations the re entry delay can be reduced or even eliminated depending on how well motorists comply with the law Transit priority measures such as queue jumps at signals see Chapter 2 can also reduce or eliminate re entry delay Coefficient of Variation of Dwell Times Based on field observations of bus dwell times in several U S cities reported in TCRP Report 26 the coefficient of variation of dwell times the standard deviation of dwell times divided by the mean dwell time typically ranges from 40 to 80 with 60 recommended as an appropriate value in the absence of field data Failure Rate The probab
133. time 2 11 1 18 2 19 4 4 9 6 14 4 15 1 6 8 4 11 8 12 3 8 7 2 9 6 10 0 10 6 0 7 6 7 8 20 second dwell time 2 10 5 16 5 17 5 4 8 8 12 4 13 0 6 7 3 9 8 10 1 8 6 0 7 9 8 1 10 5 1 6 3 6 4 30 second dwell time 2 9 9 15 1 15 9 4 7 9 10 9 11 3 6 6 5 8 4 8 7 8 5 5 6 7 6 9 L 10 4 5 5 3 5 4 40 second dwell time 2 9 4 14 0 14 6 4 7 3 9 7 10 1 6 5 9 7 4 7 6 8 4 9 5 9 6 0 10 4 0 4 7 4 7 50 second dwell time 2 8 9 12 9 13 5 4 6 7 8 8 9 1 6 5 4 6 6 6 7 8 4 4 5 2 5 3 10 3 6 4 1 4 2 60 second dwell time 2 8 5 12 1 12 6 4 6 3 8 0 8 2 6 5 0 5 9 6 0 8 4 0 4 7 4 7 10 3 3 3 7 3 7 NOTE Data based on field measurements Traffic delays shown reflect peak conditions Dwell times are average dwell times Part 2 BUS TRANSIT CAPACITY Page 2 95 Appendix B Exhibits in U S Customary Units Transit Capacity and Quality of Service Manual This page intentionally blank Part 2 BUS TRANSIT CAPACITY FINAL DRAFT Page 2 96 Appendix B Exhibits in U S Customary Units
134. tive the bus stop vehicle capacity equals the number of loading areas times the vehicle capacity of each loading area since buses are able to maneuver in and out of the loading areas independently of other buses Linear loading areas on the other hand have a decreasing effectiveness as the number of loading areas increases because it is not likely that the loading areas will be equally used Buses may also be delayed in entering or leaving a linear loading area by buses stopped in adjacent loading areas Traffic Signal Timing The amount of green time provided to a street that buses operate on affects the maximum number of buses that could potentially arrive at a bus stop during an hour Bus Lanes A bus lane is any lane on a roadway in which buses may operate It may be used exclusively by buses or it may be shared with other traffic The vehicle capacity of a bus lane is influenced by the capacity of the critical bus stop located along the lane which typically is the stop with the highest volume of passenger movements However the critical stop might also be a stop with an insufficient number of loading areas Bus lane capacity is also influenced by the following operational factors Part 2 BUS TRANSIT CAPACITY Bus Lane Type The vehicle capacity procedures define three bus lane types Type 1 bus lanes have no use of the adjacent lane Type 2 bus lanes have partial use of the adjacent lane which is shared with other traffic and T
135. tments at Intersections When buses operate in mixed traffic as is typical the interference caused by general traffic decreases bus speeds and lowers overall bus vehicle and person capacity The bus preferential treatments described in this section compensate for these interferences by removing or reducing sources of delay resulting in increased bus speeds When considering implementing bus preferential treatments the total change in person delay including both passengers in buses and motorists should be taken into account Signal Priority Bus signal priority measures include passive systems pre timed modifications to the signal system adjusted manually to determine the best transit benefit while minimizing the impact to other vehicles and active systems which adjust the signal timing after sensing the arrival of a bus Exhibit 2 25 lists common bus signal priority systems Exhibit 2 25 Bus Signal Priority Systems Treatment Description Passive Priority Adjust cycle length Reduce cycle lengths at isolated intersections Split phases Apply multiple phases while maintaining original cycle length Areawide timing plans Preferential progression for buses through signal a ee a Ee ee Bypass metered signals Buses use special reserved lanes special signal phases or are rerouted to non metered signals Active Priority Phase extension Increase phase time I Early start Reduce other phase times
136. to volumes right turn auto volumes and bus volumes in the lane For stop 1 frer 1 0 P 0 15 PEDS 2100 350 0 0 15 100 210 du 2 o fer 0 843 Page 2 78 Chapter 8 Example Problems Transit Capacity and Quality of Service Manual 2 Calculate the right turn lane capacity For stop 1 c Vo e fus fuv Sater c 1900 vph 0 45 0 84 0 971 0 90 0 843 c 529 vph 3 Calculate the mixed traffic For stop 1 18 interference factor from Equation 2 y Js 1 fi I C 1000 59 529 f 20235 4 Calculate the loading area vehicle For stop 1 capacity from Equation 2 4 3 600 g C t g Cu Z e t es 3 600 0 45 10 0 45 30 1 44 0 60 30 B 33 bus h 5 Calculate the curb lane s bus vehicle For stop 1 capacity at this bus stop from B B Equation 2 19 mN afi B 33 bus h 1 85 0 25 B 15 bus h Summary table for all stops Stop Pr far c v f B B 1 0 795 0 843 529 440 025 33 145 2 0 588 0 828 519 340 0 41 29 22 3 0 417 0 838 525 240 0 59 26 28 4 0 769 0 811 509 390 031 45 26 The Results Although bus stop 3 has the highest dwell time and the lowest individual loading area vehicle capacity the curb lane bus capacity is actually greatest at this stop because right turn interferences are greater at the other stops The critical bus stop for
137. to traffic bus direction of travel to avoid blocking Increases riding comfort traffic while passengers board and because buses don t need to alight pull in and out of stops Bicycle lanes require special e Increases on street parking by consideration eliminating need for taper associated with bus pullouts Increases space for bus stop amenities Reduces pedestrian street crossing distances Boarding Increases bus speed by Requires at least two travel lanes in Islands allowing buses to use faster bus direction of travel and a significant automobile parking maneuvers e speed difference between the two lanes Requires more right of way than other treatments Pedestrian and ADA accessibility comfort and safety issues must be carefully considered May significantly impact adjacent land uses both business and residential Requires on going enforcement Bus Stop e Uses existing signal Relocation progression to bus advantage Turn Reduces travel time by Restriction eliminating need for detours to Exemption avoid turn restrictions Exclusive e Increases bus speed by Bus Lanes reducing sources of delay Improves reliability Increases transit visibility May increase walking distance for passengers transferring to a cross street bus Potentially lowers intersection level of service Safety issues must be carefully considered Traffic parking effects of eliminating an existing travel or parking lane must
138. top speed adjustment factor using Equation 2 17 6 Calculate the bus bus interference factor interpolating from Exhibit 2 55 7 Calculate the bus travel speed from Equation 2 16 8 Calculate the time to travel the 1080 meter analysis section with and without the exclusive bus lane 9 Calculate the change in person minutes of travel time for transit passengers b Determine Automobile Travel Times 10 Using the procedures provided in the Highway Capacity Manual 2000 calculate the average travel speeds for automobiles on the street without the exclusive bus lane there are several steps to this process which are not shown here 11 Repeat Steps 10 for the exclusive bus lane scenario 12 Calculate the time to travel the 1080 meter analysis section with and without the exclusive bus lane 13 Calculate the change in person minutes of travel time for automobile passengers including the added delay to the 950 diverted right turning vehicles The Results EG _ 135 Y 60 AQUI f f 0 92 Vis Vf V 12 7 km h 0 79 0 92 V 29 2 km h t Without 1 08 km 7 5 km h t 8 6 min 0 14 hr With 1 08 km 9 2 km h t 7 0 min 0 12 hr At 10 40 30 50 8 6 7 0 At 3040 person minute decrease S 17 2 km h S 15 8 km h Without 1 08 km 17 2 km h t 3 8 min 0 063 hr With 1 08 km 15 8 km h 2 4 1 min 0 068 hr At 120
139. traffic lanes have two or more traffic lanes in the direction the bus operates Traffic can use any of the lanes but buses typically operate in the curb lane Exhibit 2 58 illustrates a Type 2 mixed traffic bus lane There are no Type 3 mixed traffic bus lanes Exhibit 2 57 Type 1 Mixed Traffic Bus Lane Portland OR Part 2 BUS TRANSIT CAPACITY Page 2 59 Mixed traffic is the most common bus operating environment in North America Mixed traffic bus capacity is calculated similarly to exclusive arterial street bus lanes except that the interference of other traffic sharing a lane with buses must be accounted for Bus lane types described Chapter 5 Mixed Traffic Transit Capacity and Quality of Service Manual Mixed traffic adjustment factor This mixed traffic bus capacity procedure is an extension of the exclusive bus lane capacity procedures developed by the TCRP A 7 project The theoretical basis exists for the mixed traffic procedures but they have not yet been validated in the field Part 2 BUS TRANSIT CAPACITY Exhibit 2 58 Type 2 Mixed Traffic Bus Lane Vancouver BC Les CALCULATING VEHICLE CAPACITY The volume of mixed traffic sharing the curb lane with buses affects bus vehicle capacity in two ways 1 the interference caused by other traffic in the lane particularly at intersections which may block buses from reaching a stop or may delay a bus blocked behind a queue of cars and 2
140. trative CBD busway vehicle and person capacities are given in Exhibit 2 42 for a variety of bus types and service conditions The key assumptions are e Fares are pre paid at CBD busway stations This allows all doors to be used for loading which greatly decreases the service time per passenger since several passengers can board at the same time e Fifty percent of the maximum load point passengers board at the heaviest stop A peak hour factor of 0 67 is assumed e No delays due to signals grade separated busway e The bus clearance time at stops is 10 seconds The design failure rate is 7 5 and a 60 coefficient of variation is assumed Part 2 BUS TRANSIT CAPACITY Page 2 40 Chapter 3 Busways and Freeway HOV Lanes Transit Capacity and Quality of Service Manual e Three linear loading areas are provided at each station e The maximum load point passenger volume is limited to 40 passengers per bus for standard buses and 60 passengers per bus for articulated buses this corresponds to a load factor of approximately 1 00 and provides a seat for all passengers Exhibit 2 42 Illustrative CBD Busway Capacities l Loading Condition l A B C D Stations On Line Off Line _ On Off On Off On off On Off Passengers boarding at heaviest station Boarding passengers per bus 20 20 20 20 20 20 30 30 Boarding time per passenger o 2 0 2 0 12 12 0 7 0 7 0 5 0 5 Dwell time s 40 0 40 0
141. treet bus lanes policy and cost considerations usually dictate the lower limit for bus volumes that warrant busway or freeway HOV lane treatments Lower minimum vehicle thresholds can be expected and are usually accepted with busways than with HOV lanes however the minimum vehicle threshold may be higher in a heavily congested corridor than in one with lower levels of congestion Non users in heavily congested areas may be much more vocal about a facility they feel is under utilized than commuters in a corridor where congestion is not at serious levels Whenever considering providing busway or HOV facilities the perceptions of commuters and the public as well as any unique local conditions should be considered when developing minimum operating thresholds Exhibit 2 37 presents typical minimum freeway HOV lane operating thresholds in vehicles per hour per lane based on U S experience Exhibit 2 37 Typical Busway and HOV Lane Minimum Operating Thresholds veh h lane Ren Facility Type t Minimum Operating Threshold Separate right of way HOV 800 1 000 Freeway exclusive two directional 400 800 Freeway exclusive reversible 400 800 Freeway concurrent flow 400 800 Freeway contraflow HOV 400 800 HOV queue bypass lanes 100 200 Exhibit 2 38 presents general planning guidelines for busways and bus priority treatments associated with freeways For more information on busway and freeway HOV facility plann
142. tributed Y Assuming bus use of the mixed traffic lane to pass other buses the heavy vehicle saturation flow adjustment factor fuv is 0 968 Y The area saturation flow adjustment factor is 0 90 for a CBD Y The bus stop location factor f is 0 50 for a Type 2 exclusive bus lane from Exhibit 2 48 Y For pre timed signals the actuated control adjustment factor K is 0 50 Y For on line stops assume a 10 second clearance time Y Za 1 44 for a 7 5 bus stop failure rate from Exhibit 2 15 Y Assume a 60 coefficient of variation of dwell times Y The adjustment factor K for random bus arrivals from Equation 2 10 is 0 50 Y For two linear on line berths the number of effective berths Nes is 1 85 from Exhibit 2 17 Y From Example Problem 6 the capacity of the lane adjacent to the bus lane is 747 vph Y Average bus speeds under the mixed traffic operation described in Example Problem Part 2 BUS TRANSIT CAPACITY 6 are 7 5 km h 4 7 mph Page 2 84 Chapter 8 Example Problems Outline of Solution Transit Capacity and Quality of Service Manual All of the input parameters are known Travel speeds will be calculated for passenger vehicles and buses with and without the exclusive bus lane using methodologies from the Highway Capacity Manual 2000 These speeds will be converted to travel times over the length of the 1080 meter 3520 foot analysis section Using the vehicle occupancies given above the travel time differe
143. ty given by Equation 2 7 if typical passenger trip lengths are short relative to the length of the bus route or bus lane The maximum person capacity of a bus lane at its maximum load point is determined by the bus lane s maximum vehicle capacity Pip max Pay B PHF mlp max Equation 2 8 where maximum person capacity of a bus route or bus lane at its maximum load point p h and B bus lane vehicle capacity bus h from the appropriate Chapter 3 4 5 procedure P mlp max Part 2 BUS TRANSIT CAPACITY Page 2 22 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual PLANNING APPLICATIONS Exhibit 2 20 summarizes the bus vehicle and person capacity factors and calculations identified in this chapter and suggests ways that each can be improved to provide additional capacity Note that in some cases increasing capacity requires a trade off with decreased quality of service Exhibit 2 20 Factors Influencing Bus Capacity Item Ways To Improve Each Item CAPACITY FACTORS Greater use of pre paid fares Use low floor vehicles Encourage one way door flows on two door buses Provide multiple stream doors for boarding and alighting e Increase bus frequency to reduce the number of standees e Implement proof of payment fare collection e Use on line stops e Enact and enforce laws that require cars to yield to buses re entering a street e Implement queue jumps at traffic signals Coeff
144. uing 81 to 100 90 Forced Flow Poor Operation over 100 110 Results in more than one lane operation Person capacity The people per hour that can be served by varying bus flow rates and passenger load factors are given in Exhibit 2 22 This table provides a broad person capacity planning guide assuming that key boarding points are sufficiently dispersed to achieve these bus loads It suggests maximum person flow rates of about 6 450 people per hour per lane on downtown streets and 8 700 people per hour per lane on arterial streets Corresponding maximum values for seated passenger flow rates are 4 300 and 5 800 people respectively Exclusive use of articulated buses would increase these values by 15 to 20 percent Exhibit 2 22 Maximum Bus Passenger Service Volumes For Planning Purposes Hourly Flow Rates Based on 43 Seats Per Bus i vvA voeu uerm Passengers Seat Buses per 0 00 0 51 0 76 1 01 1 26 Hour 0 50 0 75 1 00 1 25 1 50 ARTERIAL STREETS 25 or less 535 805 1 075 1 340 1 610 26 to 45 965 1 450 1 935 2 415 2 900 46 to 75 1 610 2 415 3 225 4 030 4 835 76 to 105 2 255 3 385 4 515 5 640 6 770 106 to 135 2 900 4 350 5 805 7 255 8 705 CBD STREETS g 20 or less 430 645 860 1 075 1 290 21 to 40 860 1 290 1 720 2 150 2 580 41 to 60 1 290 1 935 2 580 3 225 3 870 61 to 80 1 720 2 580 3 440 4 300 5 160 81 to 100 2 150 3
145. ume of buses operating on a roadway coupled with a high degree of bus and automobile congestion exclusive bus lanes may be considered to provide more attractive and reliable bus service Most bus lanes take the form of reserved bus lanes on city streets usually in the same direction as the general traffic flow There are a number of bus only streets such as Denver s 16 Street Portland s Fifth and Sixth Avenue Transit Mall and Vancouver s Granville Mall Contraflow center lanes in Montr al with center median waiting are unusual but have been successful Policy and cost considerations generally set the lower limit for bus volumes that warrant priority treatments on arterials while bus vehicle capacity sets the upper limit A study of bus operations in Manhattan recommended the following desirable maximum a m peak hour bus volumes for arterial street bus lanes e Two lanes exclusively for buses 180 buses hour e One lane exclusively for buses partial use of adjacent lane 100 buses hour e One lane exclusively for buses no use of adjacent lane 70 buses hour e Buses in curb lane in mixed traffic 60 buses hour Exhibit 2 33 presents general planning guidelines for bus priority treatments on arterial streets A comparison of person volumes on buses operating in mixed traffic with person volumes in other vehicles operating on the street can also be used to help decide when to dedicate one or more lanes to exclusive bus use Part 2 B
146. us operations reduces the street vehicle capacity by one lane if buses stay in the lane Type 1 and right turns are prohibited or made from the second lane Allowing right turns from a Type 1 bus lane reduces street vehicle capacity by less than one full lane e A dual bus lane Type 3 reduces arterial vehicle capacity by up to two lanes Because dual lanes usually would be implemented when buses already preempt most of the curb lane the actual capacity reduction in arterial traffic would be less The Madison Avenue dual bus lane experience in New York indicates that prohibiting right turns eliminating weaving movements and strict enforcement of regulations actually increased general traffic flow and speeds over what was experienced with an existing Type 2 bus lane e The effects of a Type 2 bus lane where buses may enter the adjacent lane will be between those of the Type 1 and Type 3 lanes For low bus volumes buses entering the mixed traffic lane would have little effect on the capacity of the mixed traffic lane As bus volumes in a Type 2 lane increase their impact on the adjacent lane increases to a point where some traffic is discouraged from using the adjacent lane The passenger vehicle equivalency of a bus traveling without stops is estimated in the Highway Capacity Manual at 1 5 2 0 passenger vehicles However for Type 2 bus lanes merging weaving and diverging maneuvers could raise this equivalency to 3 4 or more The effects of
147. y Exhibit 2 52 illustrates the same situations except that the 20 buses per hour employ a two stop skip stop operation and the adjacent lane is assumed to have a v c ratio of 0 5 For a given right turning volume the corresponding bus lane vehicle capacity is about 67 higher than if skip stops were not used Part 2 BUS TRANSIT CAPACITY Page 2 50 Chapter 4 Exclusive Arterial Street Bus Lanes Transit Capacity and Quality of Service Manual Exhibit 2 51 Illustrative Exclusive Bus Lane Vehicle Capacity Non Skip Stop Operation g C z 0 5 Near side Stops 2 Linear Berths Bus Lane Vehicle Capacity bus h 0 50 100 150 200 250 300 350 400 Right Turning Volume veh h 100 peds 60 s dwell 400 peds 60 s dwell 800 peds 60 s dwell ipis 100 peds 30 s dwell 400 peds 30 s dwell 800 peds 30 s dwell NOTE Assumes 15 second clearance time 25 queue probability 60 coefficient of variation of dwell times permitted right turn signal phasing shared right turn lane and bus volumes minimal in relation to right turn volumes Par 1 0 Exhibit 2 52 Illustrative Exclusive Bus Lane Vehicle Capacity Skip Stop Operation gC z 0 5 Near side Stops 2 Linear Berths v c 0 5 140 Em hii T o B gt 100 Wi a as re e ms f Eo 5 40 ax EI o 0 0 50 100 150 200
148. ype 3 bus lanes provide for exclusive use of two lanes by buses The curb lane of Type 1 and 2 lanes may or may not be shared with other traffic The greater the degree of exclusivity of the bus lane and the greater the number of lanes available for buses to maneuver the greater the bus lane capacity Bus lane types are illustrated and discussed in more detail in Chapter 4 Exclusive Arterial Street Bus Lanes and in Chapter 5 Mixed Traffic Skip Stop Operation Bus lane capacity can be increased by spreading out bus stops so that only a portion of the routes using the bus lane stop at a particular set of stops Skip stop operation is different than limited stop service where certain buses on a particular route do not stop at selected stops This block skipping pattern allows for a faster trip and reduces the number of buses stopping at each bus stop although it also increases the complexity of the bus system to new riders and may also increase passenger walking distances to bus stops Skip stop operation is discussed further in Chapter 2 Operating Issues Platooning When skip stops are used forming buses into platoons at the start of the skip stop section maximizes the efficiency of the skip stop operation Each Page 2 12 Chapter 1 Bus Capacity Basics Transit Capacity and Quality of Service Manual platoon is assigned a group of stops in the skip stop pattern to use The platooned buses travel as trains through the skip stop section

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