Home

A Bus Signal Priority System Using Automatic Vehicle Location

1. 13 2 4 3 Priority Phase Selection and Configuration ener 14 3 Adaptive Transit Signal Priority Strategy sess 16 16 16 3J1 2 Far Side BUS Stop istos eer etr taa Ete Eae 17 3 2 Estimation of Bus Dwell Time at Bus 18 3 3 Priority Acknowledgement Rules 2 eere enne ennt nnne 18 3 3 1 Priority Request Time Time Factor eene enne nnne 19 3 3 2 Bus Schedule Adherence Lateness Factor LF seen 19 3 3 3 Number of Passengers Passenger Factor 2 22001 020 2 eene enne 19 3 4 Signal Timing Treatment 042228 no ooi Rr rete i d AT ee 19 3 5 Signal Priority 1 20 4 Experiment Setup and Testi entente di 21 21 21 Wi Fi Communication Latency 23 1 802 1 4 1 2 Program Signal Controller and Signal Priority Interface see 23 4 2 Program Low Priority Pre Emption Input esses ener enne 24 4 2 1 25 Field Testing Como Avenue and 29 Avenue 56 26 4 3 5 Resultsand Data 29 5 1 Analyze Data Collected From Onboard Equipment sse ener 29 5 1 1 Signal Priority Request for Gre
2. Main Street Traffic Light Figure 5 9 Vehicle Speed Profile and TSP Request Westbound 5 2 Phasing and Timing Information from Signal Controller We tried to obtain real time signal timing and phasing information from the EPAC traffic controller through the the serial communication interface on the traffic controller A serial communication analyzer was utilized to monitor the serial port activities Detail information regarding the serial analyzer and the signal controller serial communication are included in Appendix F It is difficult to find out the timing and phasing commands without the knowledge of the serial communication commands Signal controller vendor uses special software MarcNX www itssiemens com to communicate with the traffic controller though the serial communication interface MarcNX software allows monitoring and controlling of traffic from a central computer center in the Microsoft Windows environment Due to the proprietary nature of the communication protocol the vendor is unwilling to share the information with us One possible solution to get the controller timing and phasing information is to tap onto the controller cabinet back panel with a simple circuitry design as shown in Figure 5 10 The data collection system as shown in Figure 5 10 was developed by Professor Henry Liu and his research group at University of Minnesota The SMART SIGNAL systems were deployed on over a dozen of actuated intersections in the Twin
3. SIGNAL PHASING AND TIMING INFORMATION OF COMO amp 2978 AVENUE 1 Geometry Layout and Phase Assignment NER ac zs we sung loc T OF n E ng cr p WALSAS NI aAQN au 2 1 NI OTAN NI iM T340H SALA IL 8810N 58925 Ervapn Care uasa s APOAY TENEIS EAM OFC AD SITOUVELNNTA PA OIN EA Cae 117 51 306 0110 2 Sue X Mal E mEt Tiga 14 7 nijsduad aie HaTloulHDna SAV 1 3 eje 2 perele e e ela 9 89 TAT Jj va AG VIVES ova Wao alme or MOM EITA RING 9 TEA TSM 30153120 angio ta 57 NHLI OA 1172 024v130 LEN UON3LX 1092 Ct do Y mad i ZW PST sd pu ETT LHYHO
4. lt DLE gt lt STX gt lt ACK gt lt NUL gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt B7 F3 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt F 1 lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SOH gt lt DLE gt lt ETX gt B9 A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt SOH gt lt NUL gt 78 lt NUL gt lt NUL gt lt NUL gt 96 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt H 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 2D 44 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt STX gt lt DLE gt
5. Detail information about the Garmin GPS receiver is included in Appendix G The mobile embedded signal priority system 15 packaged in a NEMA enclosure as shown in Figure 2 13 This design allows us to easily deploy the prototype system to various field testing and validation at different intersections or on different buses The wireless signal priority strategy will be tested using the Minneapolis Wi Fi network and the 5 9 GHz DSRC radio Detail testing results are discussed in Chapter 4 VID Passenger Stop Location Traffic Bus Schedule Door Status etc Controller Antenna Antenna Modem Modem TXIRX 8 GPS Receiver Tx Rx GPS AVL Ex Door Open Close APC UMN TSP Equipment Processor OBE Figure 2 12 GPS and Wireless Based Signal Priority System Embedded System Power Converter Figure 2 13 The Embedded Signal Priority System Packaged in a NEMA Enclosure 2 3 2 Software Design and Implementation Software design of the OBE includes three major processes GPS string processing OBE wireless communications and bus computer interface as shown in Figure 2 14 The GPS data processor parses the GPS sentences every 200 ms since the GPS receiver updates its location five times per second Software design of the OBE includes the signal priority algorithm RSE wireless communications 11 traffic controller interfaces The signal priority algorithm developed in the phase one simulation study wa
6. Dim DEG 2 RAD As Double Math PI 180 0 Dim constants As Coord Const New Coord Const constants setZone 2203 NAD83 MN South zone Dim mySPCSxy As Point2D New Point2D sin phiO Math Sin constants phi zero DEG 2 RAD gamma constants lambda zero myLatLong getY sin 0 DEG 2 RAD sin phi Math Sin myLatLong getX DEG 2 RAD Ln1 Math Log 1 0 sin phi 1 0 sin phi Ln2 Math Log 1 0 constants E sin phi 1 0 constants E sin phi Q 0 5 Ln1 constants E Ln2 constants K Math Exp Q sin phiO mySPCSxy setX constants E zero R Math Sin gamma mySPCSxy setY constants Rb constants Nb R Math Cos gamma Return mySPCSxy End Function Private Sub btnUDP_Click ByVal sender As System Object ByVal e As System EventArgs Handles btnUDP Click If frmUdpComm Is Nothing Then frmUdpComm New UDPComm frmUdpComm Show End If End Sub Private Sub Timer2 Tick ByVal sender As System Object ByVal e As System EventArgs Handles Timer2 Tick parse lat long alt etc Dim 5 idx en idx i As Integer Fori 1To6 st_idx en_idx 1 en idx GPVTG_str IndexOf st_idx If en_idx gt 0 And st_idx lt gt en_idx Then Select Case i Case 2 course Heading_str GPVTG_str Substring st_idx en_idx st_idx txtHeading Text Heading_str Case 3 reference T true heading Case 4 course Case 5 M magnetic heading Case 6 Speed Knot str GPVTG str Substring st idx id
7. F 4 Device Communications We tried with the following values for communicating with the traffic controller lt EOT gt A00 lt ENQ gt Got Reply as lt DLE gt 0 lt DLE gt lt EOT gt lt a00 gt lt ENQ gt Got Reply as 0 lt STX gt lt DLE gt lt ETX gt 1 No Reply F 10 APPENDIX G GARMIN GPS RECEIVER G 1 Garmin GPS 18 Descriptions The GPS 18 5Hz is an OEM GPS sensor for use in machine control guidance and agricultural applications that require 5 Hz position and velocity reports from a small highly accurate GPS receiver This 12 parallel channel WAAS enabled GPS comes with an integrated magnetic base for easy mounting The puck like receiver is 2 4 inches in diameter and weighs just a few ounces making it an ideal solution for applications where space is at a premium The GPS 18 5Hz stores configuration information in non volatile memory so it starts up quickly each time you use it It also has a real time clock and raw measurement output data for sophisticated high precision dynamic applications For extra precision it offers 5 Hz Measurement Pulse Output with rising edges that align to precise 0 2 second increments of UTC time as long as the receiver has reported a valid and accurate position within the past 4 seconds Figure G 1 Garmin GPS 18 5Hz Unit G 2 Test Interface A test program with Graphical User Interface GUI as shown in Figure G 2 was initially developed to test and validate the features and funct
8. gt gps_ year 1900 local_time gt tm_year myGPS gt gps_month 1 local_time gt tm_mon myGPS gt gps_day local_time gt tm_mday break latitude data atof NMEA fields field index 1 data_deg floor data 100 0 degree myGPS gt latitude data_deg data data_deg 100 0 60 0 break N S indicator myGPS gt lat_dir NMEA fields field index 1 0 if myGPS gt lat_dir S myGPS gt latitude myGPS gt latitude break longitude data atof NMEA fields field index 1 data_deg floor data 100 0 degree myGPS gt longitude data_deg data data_deg 100 60 0 break EW indicator myGPS gt long_dir NMEA_fields field_index 1 0 if myGPS gt long_dir W myGPS gt longitude myGPS gt longitude break Position fix myGPS gt position_fix fields field index 1 break Satellite used myGPS gt num_satellites atoi NMEA_fields field_index 1 break myGPS gt hdop atof NMEA fields field index 1 break Altitude meter myGPS gt altitude atof NMEA fields field index 1 break checksum convert to XY convert to cartesian myGPS break 11 end of switch field index break case GPVTG ID update GPVTG sentence Iprintf GPVTG d switch field_index case 8 s n field_index NMEA_fields field_index 1 speed Km h myGPS gt speed 1000 0 3600 0 atof NMEA fields field inde
9. is bus speed and 18 the traffic delay on bus route 17 Therefore the estimated time for westbound bus passing intersection i can be calculated as follows tua 1 7 Where t is the current time sec The desired signal priority would need to begin at 6 seconds prior to the bus arriving intersection i s where is defined as equation 5 The signal priority service can be ended at f T where Tis the time for bus to cross intersection i If both beginning and ending t of the estimated priority service fall within the green split no action needs to be taken by the controller If falls in the green split and E falls in the red split extended green time is need to ensure bus could pass the intersection However if the estimated beginning of priority service time falls within the red light period red signal truncation or early green light treatment 15 needed to offer bus priority 3 2 Estimation of Bus Dwell Time at Bus Stop Ghanim et al 2007 developed an artificial neural network modeling tool to predict the bus arrival time on approaches with nearside bus stops based on observed travel time boarding and alighting demand and current traffic condition We used a simpler linear regression model to predict dwell time based on the number of boarding and alighting passengers average headway between buses schedule adherence number of door on the
10. lt DC4 gt lt ACK gt 21 lt DLE gt lt ETX gt A0 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 21 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt C5 8D lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 22 lt DLE gt lt ETX gt A0 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 22 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt
11. lt DC4 gt lt ACK gt 29 lt DLE gt lt ETX gt A7 A2 F 9 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 29 lt NUL gt lt NUL gt lt NUL gt lt NUL gt 78 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt EOT gt lt NUL gt lt NU L gt lt NUL gt lt NUL gt lt CAN gt lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 38 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt EOT gt lt DLE gt lt ETX gt 4A 35 lt DLE gt 30 lt EOT gt F 3 Difference in Above Two Dumps Compare lt C TSP EagleController 9th Jan 10th Jan New Record HexVal7 txt 10757 bytes with gt C TSP EagleController 9th Jan 10th Jan New Record HexVal6 txt 10757 bytes 6c6 lt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC 1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 2F AB lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C6 D2 gt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 25 D1 lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3F 29 14c14 lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31433 lt DC1 gt 5C 25 lt NUL gt lt N
12. lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt BS gt lt DLE gt lt ETX gt HBFHF2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt BS gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt F6 83 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt HT gt lt DLE gt lt ETX gt BE 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt HT gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL g
13. lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt C5 8D lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 22 lt DLE gt lt ETX gt A0 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 22 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt F2 AB lt DLE gt 30 F 8 lt gt lt gt 41 30 30 lt gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 23 lt DLE gt lt ETX gt A1 lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 23 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL g
14. lt time h gt include bus_obu h int main int argc char argv int portnum char buffer BUFFER_SIZE char text 20 int nbytes 0 char dataStr BUFFER_SIZE int strPtr 0 i 0 initialize NMEA_fields NMEA fields char malloc NMEA_FIELD_SIZE sizeof char for i 0 icNMEA_FIELD_SIZE i NMEA fields i char malloc 32 sizeof char 1 init myGPS myGPS gps malloc sizeof gps initialize serial port if fd open_port 1 1 open serial port COM1 printf Error opening 1 return 1 init_port amp fd 38400 set serial port to 38400 8 n 1 thread 1 read gps sentences pthread_t thread1 char message1 read GPS int ireti Create independent threads each of which will execute function iret1 pthread_create amp thread1 NULL readGPSStr void message1 thread 2 communicate with RSU server pthread t thread 2 char message2 client int iret2 Create independent threads each of which will execute function iret2 pthread create amp thread2 NULL clientComm void message2 pthread join thread1 NULL pthread join thread2 NULL if argc gt 1 while 1 infinite loop if argv 1 t transmit read GPS sentences fputs Enter text stdout fflush stdout fgets text 20 stdin sendSerial amp fd text Iprintf done n else if argv 1 r receive while n
15. 1 perror socket exit 1 host byte order their addr sin family he gt h_addrtype their addr sin port htons PORT memcpy char amp their addr sin addr s addr he gt h_addr_list 0 gt length zero the rest of the struct memset amp their addr sin zero 0 8 bind any port cliAddr sin family AF INET cliAddr sin addr s addr htonl INADDR ANY cliAddr sin port htons 0 if bind sockfd struct sockaddr amp cliAddr sizeof cliAddr 1 perror Client bind error exit 1 int sin size sizeof their addr send message to remote server if sendto sockfd message strlen message 0 struct sockaddr amp their addr sin size 1 perror Client sendto error lol if sigsetjmp recv timed out 1 printf recvfrom timed out n n return 1 set timer and handler signal SIGALRM timeout_handler alarm RECV_TIMEOUT receive numbytes recvfrom sockfd buf MAXDATASIZE 1 0 struct sockaddr amp their_addr amp sin_size clear timer and handler alarm 0 signal SIGALRM SIG_DFL if numbytes 1 perror recvfrom exit 1 buf numbytes 0 add end of data printf Client Received s n buf close sockfd return 0 mySerial c Created on May 20 2007 3 06 PM Copyright Regents of the University of Minnesota All rights reserved f Author C
16. 1 t E i 1 god gt Bus Stop j 1 Bus Bus Stop 1 Eastbound 4 Intersection 1 1 Intersection i Intersection it Figure 3 1 An East West Corridor Example for Signal Priority 3 1 Bus Stop Location Consideration 3 1 1 Nearside Bus Stop Consider the bus traveling in the eastbound as shown in Figure 3 1 Expected bus dwell time at bus stop j can be forecasted using historical dwell time statistics Expected bus travel time aj from its current location to bus stop can be calculated via T aj de 1 1 V Where 18 bus speed is the distance from the current bus location to bus stop j is bus braking stopping time and T delay Is the traffic delay on bus route The expected bus travel time T from bus stop j to intersection i can also be calculated as follows assuming the distance from the nearside bus stop to the intersection is relatively short compared to the distance needed to accelerate to running speed 16 2 4 d T E NE Eq 2 d is the distance from eastbound bus to intersection i Where is the distance from eastbound bus to bus stop j is the bus acceleration and T is the bus clearance time Therefore the predicted time at which the eastbound bus passes intersection i can be calculated as follows ta t T T Eq 3 Where t is the curre
17. 1 7 1 3 0 0 1 0 0 4 2 2 0 3 0 1 0 0 1 13 3 9 7 3 Grand Total 114 560 606 60 769 1064 467 54 612 518 155 50 178 1054 85 34 6460 54 41 2 446 59 327 452 19 8 23 458 38 8 11 6 37 126 747 6 67 Total 18 87 94 12 119 16 5 72 08 95 24 0 3 28 16 3 13 1 5 B 1 5 1 Ly Out Left 2 E 5 IS Ped North 4 19 2006 06 30 AM 4 19 2006 06 45 PM Unshifted gt Right Peds nu yel Sped 612 50 Figure B 1 Average Volume at Como and 29th Avenue APPENDIX C EMBEDDED COMPUTER SYSTEMS 1 CPU Board a an allt 3 Address Data Control System Clocking MK1451 05 UF 14 318 MHz FPLVDS National 0530 383 SMSC ACPI Disable PWRSTNE SOFT LPC47N217 PWR Control Super WO PCI Arbitration ACPI DISABLE JUMPER Figure C 1 EPM 5 Block Diagram VersaLogic EPM 5 Reference Manual USB Keyboard and USB Mouse CBR 5009A CBR 5010B CBR 1201 cons ATX Power Supply OS Installation CD ROM Figure C 2 EPM 5 Start Configuration VersaLogic EPM 5 Reference Manual C 2 Digital VO Board R104 88 C 2 1 Relay Output Control The
18. 2 a digital I O board R104 88 manufactured by Tri M Systems http www tri m com includes 8 isolated inputs and 8 relay outputs It is added to the Puma SBC to interface with traffic controller cabinet for signal priority request Detail board layout and jumper settings of the R104 I O board are documented in Appendix C 2 A HC104 power supply module as shown in Figure 2 3 is stacked under the single computer and IO module to provide 5 and 12VDC power through the pass through connectors The Puma SBC offers a CompactFlash CF http www compactflash org socket to allow removable media storage and support bootable media Linux www linux org kernel for each embedded computer is built on a Linux host machine which compiles and creates a bootable Linux OS image on a CompactFlash disk of less than 1 Gigabyte Detail instructions on building a Linux kernel on a CompactFlash disk are discussed in Appendix C 3 Figure 2 2 R104 88 Optoisolated Input and Relay Output Board Figure 2 3 HE104 50 Watt High Efficiency PC 104 Power Supply 2 2 Wireless Communication Modules Buses can communicate with intersection signal controllers using wireless technology to request for signal priority Communication between the RSE and OBE can be tested using the 802 11x WLAN or the DSRC Dedicated Short Range Communication 802 11p protocol currently under development for wireless access to and from the vehicular environment 2 2 1 Denso WAVE Radio Modems
19. 8 relays are accessed through I O memory writes The relays are grouped in set of four and the group I O memory address is an offset from the base decode address Relays are grouped as follows Group 1 Output DOI to 4 I O address Base Address Group 2 Output DOS to DO8 I O address Base Address 1 The relays are bit mapped to the lower four data lines in each group as follows nue sos se Te C 2 2 Digital Input Reading The 8 digital inputs are accessed though I O memory reads The inputs are grouped in sets of four and the group I O memory address is an offset from the base address Inputs are grouped as follows C 2 Group 1 Output to DIA I O address Base Address 2 Group 2 Output DI5 to DI8 I O address Base Address 3 The inputs are bit mapped to the lower four data lines in each group as follows Digtatingut 503 502 soo out mese impura input2 Group inputs impuro inputs C 2 3 Base Address Settings There are four decode base addresses which are jumper selectable from the address select block J18 2404 Jumper Not insta Jumper Not Instates_ Jumperinstated Jumper Not instales Jumper Not Installed Jumper Installed jumper istana sumper instanca C 3 Connection to Signal Controller Cabinet The wiring diagram of the connection between the relay output and the controller cabinet is illustrat
20. A pair of Denso DSRC radio modems as shown in Figure 2 4 was previously purchased by Intelligent Vehicles Laboratory http www its umn edu ProgramsLabs IntelligentVehicles for research on vehicle to vehicle communications for example electronic braking The Denso radio modems were early prototypes operating at 5 9GHz using the 802 11b protocol Each onboard and roadside computer was connected to a Denso modem for wireless data communications The data flow chart of the wireless communications between the roadside and onboard equipments using the Denso radio modems is displayed in Figure 2 5 The communication distance of the DSRC modems ranges around 300 meters 1000 ft The direct point to point configuration of communication provides relatively high speed of data communication Figure 2 4 Denso DSRC Wireless Modem Lam Modem amp 1 Modem 2 Figure 2 5 Wireless Communications Using the Denso Radio 2 2 2 802 11x Wireless Modules In addition to the DSRC modems two Ruckus http www ruckuswireless com MediaFlex Wi Fi modems as shown in Figure 2 6 was used to access to the Minneapolis wireless network The RSE and OBE were each connected to a Ruckus modem to establish connection to the Internet through the Minneapolis Wi Fi network as shown in Figure 2 7 Figure 2 6 Ruckus Wi Fi Modem Minneapolis Wi Fi External IP 206 55 182 230 External IP 206 55 182 229 4 Modem 1 192 1
21. Avenue test site to validate the bus signal priority algorithm using wireless communication technology The mobile design of the wireless transit signal priority system allows us to test the prototype at different intersection or on different vehicle easily The Onboard Equipment OBE as illustrated in Figure 4 14 was placed inside a minivan with GPS receiver and radio antenna mounted on the roof of the vehicle to represent a transit vehicle The onboard embedded system interfaces with the GPS and wireless communication systems to transmit vehicle location and other information for example vehicle ID route ID passenger counts door opening status and so on to the roadside equipment The Roadside Equipment RSE continuously monitors the vehicle location when the test vehicle travels within the range of the wireless communication and then generates a signal priority request to traffic signal controller as iuulstrated in Figure 4 15 s CPF m DSRC Antenna N u 57 lt 2 GPS 0000 UN at 7 Hi Onboard Equipment m Figure 4 14 Onboard Equipment Setup 27 Roadside Equipment Figure 4 15 Roadside Equipment Setup 28 5 RESULTS AND DATA ANALYSIS Vehicle location and timing of signal priority request were collected during the field testing Data analysis and problem encountered during the field testing were discussed in this chapter Figure 5 lillustrates
22. B Bus A wins if it requests earlier than bus B does where W is the request time weighting factor W 21 A W B 1 t lt t A LB W t gt t 3 3 2 Bus Schedule Adherence Lateness Factor LF LF W xT ate Where W is the bus late time weighting factor W gt 1 and T is the number of minute the bus ate was late LF 0 when bus is ahead of its schedule 3 3 3 Number of Passengers Passenger Factor PF PF W xN passenger Where W is the bus passenger count weighting factor W gt 1 and is the number of passenger passengers on the bus The priority acknowledgement functions for bus A and B are defined as follows f A TF A B x LF A PF A f B TF A B x LF B PF B Eq 9 If the priority acknowledgement function f A is greater than f B bus A will be granted signal priority No signal priority request is granted if the acknowledge function f equals zero which means there are no passengers on the bus and no delay on bus schedule adherence 3 4 Signal Timing Treatment The projected signal phase estimated arrival time for a bus passing a signalized intersection can be calculated using the equations discussed in the previous section When the projected signal phase coincides with the priority phase which is the phase where a bus requires passing through an intersection green extension is considered if the remaining green time is insufficient However if the projected arriving pha
23. Cities area to collect traffic event data triggered by inductive loop detector pedestrian calls and phasing changes Similar data collection system can be used to obtain the current active phases and timing 34 of the active phases Collected data can then be processed by the roadside equipment to adjust the appropriate timing for signal priority request 3 3 VDC Isolation Resistor 24VDC Digital Logic Detector GND Input 5 4 Digital I O Board Figure 5 10 Controller Data Collection Interface from SMART SIGNAL Project 5 3 Wireless Connection To further investigate the feasibility of using Wi Fi for transit signal priority we also set up a private wireless network to test the communication between the OBE and RSE using the 802 11x protocol The DSRC radios were replaced by a pair of Wi Fi USB adapters each connected to the OBE and RSE and a wireless router When wireless communication was initially established prior to the test vehicle traveling outside the communication range the communication link will be temporary lost as the test vehicle traveling out of the Wi Fi coverage However the communication link will be re established as the departing vehicle turned around and re entered into the wireless coverage range as shown in Figure 5 1 la If the communication between the OBE and RSE was not established as the vehicle traveling from upstream intersection to the next wireless communication was not
24. Ethernet cards USB to serial port device home phone network device and so on In order to keep the Linux kernel to a minimal size and allow the system to be bootable from a CompactFlash memory no Graphical User Interface GUI was installed on the Linux based embedded target systems A text based web browser called Lynx http lynx isc org was then installed on the embedded computer to submit authentication scripts and passphrases to the University of Minnesota wireless network or the Minneapolis Wi Fi network when using the USB wireless adapters The Ruckus modems do not require additional authentication to access the Minneapolis Wi Fi network since the Media Access Control MAC addresses on the Ruckus modems were previously registered to the Minneapolis Wi Fi network server Dynamic Host Configuration Protocol DHCP was used to obtain IP address dynamically when the wireless modem detects the network access point Detail information regarding the NDIS wrapper for the wireless adapter and the lynx text based web browser are documented in Appendix E E Figure 2 8 LinkSys Wireless N USB Network Adapter Eu Figure 2 9 Wireless Communications Using the WUSB N Wireless Adapter UMN Wireless Adapter 1 2 2 3 Wireless Router Another configuration for our wireless testing is to communicate between the RSE and OBE though a private network A LinkSys WRT310N wireless router as shown in Figure 2 10 was used as a gateway to t
25. Install the driver Code ndiswrapper i home student Driver xp 2k name inf ndiswrapper m ndiswrapper I E 3 4 Insert the module Code modprobe ndiswrapper There should be no error messages from the modprobe command If necessary add ndiswrapper to etc modules for automatic insertion at boot Next insert the wireless device if you haven t already and watch what happens with one or more of the commands iwconfig iwlist scan ifconfig exit That ifconfig command should show the wireless wlanO or 0 etc interface although not yet configured but that s another story Just a hint if you plan on using WPA security you really should then specify the wext driver with wpa supplicant not the ndiswrapper driver E 3 5 Command samples e Configure wlan0 interface to connect to UMN TSP network iwconfig wlanO essid UMN TSP e Scan and list available wireless network iwlist wlanO scan e Request for IP through wlan0 interface dhclient wlanO e Remove dhclient file process dhclient r E 4 Test University Wireless Network Using WUSB300N Adapters Connect WUSB300N to the USB drive Ensure that there is enough signal strength and verify by looking at the blue signal shown in the device E 4 1 Authentication Script for connecting with U of M wireless network In the connection script after line key space specify your student id and password for every alphabets Below is the example for following
26. Linksys Wireless N Gigabit Wireless Router Wireless N Router is gt 1 1 2 Figure 2 11 Wireless Communications Using the WUSB N Wireless Adapter and Router 2 3 Wireless Signal Priority System Integration System integration of the embedded TSP system and software design and development are the key elements in developing the wireless signal priority system as shown in Figure 2 12 The design of the OBE includes the wireless communication modules and the interfaces to the GPS receiver and other transit vehicle information such as passenger count and door opening status The RSE include the signal priority algorithm wireless communication module and the interface to traffic signal controller 2 3 1 Hardware Design and Integration A Garmin GPS 18 5Hz unit is used provide vehicle location as part of the wireless transit signal priority system The GPS 18 receiver stores configuration information in its non volatile memory which allows the GPS unit to start up quickly It also has a real time clock and raw measurement output data for sophisticated high precision dynamic applications For extra precision it offers 5 Hz measurement pulse output with rising edges that align to precise 0 2 second increments of UTC time as long as the receiver has reported a valid and accurate position within the past 4 seconds Graphical User Interface GUI was previously developed to test the performance of the GPS 18n unit
27. ROUTE 3 TRIP DATA D 1 Route 3 Trip Counts Table D 1 Bus Route 3 Trip Counts Count of Trips SAT Total East West WK Total 2 NN POB HYD gt 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 a gt ot HR HRP PHP m m nm or ADD YD NNA DN O Grand Total D 2 Map of Bus Route 3 Route 3 Effective 3 08 08 Add terminal label to allow second bus to fit in layover Downtown St Paul Layover on Cedarferside of 6th Si accom mod ates two buses Please pull forwerd as fer as possible AN Paul Figure D 1 Map of Route 3 D 2 APPENDIX E WIRELESS DEVICES E 1 Denso DSRC Wireless Modems Figure E 1 Denso DSRC Prototype E 2 LynkSys 802 11 Wireless Modules Figure E 2 LinkSys Wireless N USB Network Adapter E 3 Steps to Install Module Assistant and Ndiswrapper E 3 1 Modify the sources files etc api sources list deb http http us debian org debian etch main contrib non free deb http security debian org stable updates main contrib non free E 3 2 Install compile ndiswrapper Code Su apt get update E 1 apt get dist upgrade apt get install module assistant ndiswrapper source ndiswrapper utils prepare m a a i ndiswrapper E 3 3
28. Serial or NTCIP Interface esses 13 Figure 2 17 Wiring Diagram from R104 VO Board to Controller Cabinet esses 14 Figure 2 18 NEMA Phase Assignments 14 Figure 3 1 An East West Corridor Example for Signal Priority sse 16 Figure 3 2 Block Diagram of Transit Signal Priority Strategy essen 20 Figure 4 1 DSRC Wireless Coverage at 22nd and Franklin Avenue esset 21 Figure 4 2 Latency of DSRC Wireless Communication at 22nd and Franklin Avenue 22 Figure 4 3 DSRC Wireless Coverage at Como and 29th Avenue sese 22 Figure 4 4 Latency 01 DSRC Wireless Communication at Como and 29th 22 Figure 4 5 Latency 01 802 11x Wireless Communication at Como and 29th 4 6006 sess 23 Figure 4 6 Latency of Wireless Communication Using UMN Wi Fi Network 23 Figure 4 7 Preempt 5 Miscellaneous 24 Figure 4 8 Preempt 5 Low Priority Menu eerte trennen 24 Figure 4 9 Low Priority Signal Priority eene eren enne 25 Figure 4 10 Program Eagle Traffic Signal Controller eese ene 25 Figure 4 11 Block Diagram of Signal Priority Request 5 26 Figure 4 12 Transit Signal Priority Test 8 26 Figure 4 13 Aerial Map of Como and 29
29. Strategies for Signal Priority Transportation Research Record No 1727 pp 20 26 Skabardonis A Geroliminis N 2008 Real Time Monitoring and Control on Signalized Arterials Journal of Intelligent Transportation Systems Volume 12 Issue 2 pp 64 74 Stibor L Zang Y Reumerman H 2007 Neighborhood evaluation of vehicular ad hoc network using IEEE 802 11p Compendium of 13th European Wireless Conference Paris France April 1 4 2007 http www ew2007 org papers 1569014956 pdf accessed October 1 2007 Torrent Moreno M Jiang D Hartenstein H 2004 Broadcast reception rates and effects of priority access in 802 11 based vehicular ad hoc networks Proceedings of the 1st ACM international workshop on Vehicular ad hoc networks Association for Computing Machinery New York NY pp 10 18 Trafficware Corporation Synchro traffic signal coordination software Albany CA http www trafficware com accessed October 1 2007 Transportation Research Board 2003 Transit Cooperative Research Program TCRP Report 100 Transit Capacity and Quality Service Manual 2 Edition Part 4 Bus Transit Capacity Chapter 1 Bus Capacity Fundamentals pp 4 3 4 9 http onlinepubs trb org onlinepubs terp terp 100 part 200 pdf accessed October 1 2008 Transport Simulation Systems 2002 AIMSUN Version 4 1 User s Manual Transport Simulation Systems TSS Barcelona Spain http www aimsun com site
30. bus GPS data schedule and trip count data WenTeng Ma Sundeep Bhimireddy and Prof Henry Liu at Department of Civil Engineering for provide access to their SMART SIGNAL traffic controller cabinet for TSP testing e Jim Welna owner of Welna II Hardware on East Franklin Avenue for providing AC power access for roadside unit testing with the Minneapolis Wi Fi network e USI Wireless for providing technical support on its wireless network in Minneapolis e Tony Juettner at Brown Traffic Products Inc for providing information on EPAC traffic controller TABLE OF CONTENTS T Introduction 1 AN or 1 1 2 Researcli ObJec yes u 2 er a e eR te Per irt ree nete re e E e 1 1 3 Literature Review oie irren NR RR cos NN P e e ed e mun dent 1 5 2 1 Embedded Computers o Rb 5 2 2 Wireless Communication Modules esses 6 2 2 1 Denso WAVE Radio Modems trennen rentrer innen 6 2 2 2 802 1 1 Wireless eet ettet iii 7 2 253 Wireless use pt notat udi dor Eua Certa epit edo 9 2 3 Wireless Signal Priority System Integration sees 10 10 11 2 4 Signal Control Interface aee tie e data 12 DAL S1ghab Priority coiere E Pe 5 e e ee Week ooze ves 12 nennen enne
31. e ntt oe No Data Communication 0 T T T T Wireless Communication Latency ms 39 35 4 39 44 1 39 527 40 01 3 40 10 0 40 18 6 Time mm ss s Figure 4 2 Latency of DSRC Wireless Communication at 22nd and Franklin Avenue Similar testing was performed at the intersection of Como and 29 Avenue to compare the performance of DSRC radio at different location As shown in Figure 4 3 the wireless coverage range at Como test site is much shorter than that at Franklin Avenue The shorter communication range was probably caused by the significant amount of trees along the Como Avenue which might contribute additional reflections absorptions and refractions The average wireless data communication latency using the Denso DSRC radio ranges between 3 and 5 milliseconds as shown in Figure 4 4 at Como and 29 Avenue Y meter 321220 Cc 3 321200 321180 Signal Coverage 270 m 0 17 miles 321160 861900 861950 862000 862050 862100 862150 862200 862250 862300 X meter Figure 4 3 DSRC Wireless Coverage at Como and 29th Avenue 8 5 6 LE sS E 99h 4 mmm gt 11A mm o 8 4 AAA mn nn mn V Cte C 99999 2 v No Data Communication 2 0 E e e LO 59 11 0 59 19 7 59 28 3 59 37 0 59 45 6 59 54 2 00 02 9 00 11 5 00 20 2 Time
32. eie ve deest Neg uei G 2 LIST OF FIGURES Figure 2 1 Puma 104 Plus Single Board Computer esses 5 Figure 2 2 R104 88 Optoisolated Input and Relay Output 6 Figure 2 3 HE104 50 Watt High Efficiency PC 104 Power 1 1 401000 6 Figure 2 4 Denso DSRC Wireless 7 Figure 2 5 Wireless Communications Using the Denso 7 Figure 2 6 Ruckus Wi Fi Moden 7 Figure 2 7 Wireless Communications Using the Ruckus 8 Figure 2 8 LinkSys Wireless N USB Network 9 Figure 2 9 Wireless Communications Using WUSB N Wireless Adapter sss 9 Figure 2 10 Linksys Wireless N Gigabit Wireless Router 10 Figure 2 11 Wireless Communications Using the WUSB N Wireless Adapter and Router 10 Figure 2 12 GPS and Wireless Based Signal Priority 11 Figure 2 13 The Embedded Signal Priority System Packaged in a NEMA Enclosure 11 Figure 2 14 Software Design of the Signal Priority System eese 12 Figure 2 15 Eagle EPAC M40 Traffic Signal Controller sse 13 Figure 2 16 TSP Initiation Thrugh
33. gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 2F AB lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C6 D2 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 F 5 lt DLE gt lt STX gt lt EM gt lt DC4 gt 2F lt DLE gt lt ETX gt lt ESC gt 69 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 2F AB lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C6 D2 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt NUL gt lt DLE gt lt ETX gt B8 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt NUL gt lt NUL gt 46 lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 5CHA2 lt DLE gt 30 lt EOT gt lt EOT gt 41 30
34. lt DLE gt lt ETX gt 22 5C lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ENQ gt lt DLE gt lt ETX gt BB 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ENQ gt lt NUL gt 96 lt NUL gt lt NUL gt lt NUL gt 96 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 32 B7 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 F 6 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ACK gt lt DLE gt lt ETX gt BB 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ACK gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt NUL gt lt NUL gt 40 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt N
35. lt DLE gt lt STX gt lt ACK gt lt SI gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 50 36 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 20 lt DLE gt lt ETX gt A1 F2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt BS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt lt N UL gt lt NUL gt lt NUL gt lt CAN gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 38 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt NUL gt lt DLE gt lt ETX gt CC A5 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt
36. lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt H8BHCD lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SO gt lt DLE gt lt ETX gt BC 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt F 3 lt DLE gt lt STX gt lt ACK gt lt SO gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 98 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SI gt lt DLE gt lt ETX gt BD C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt
37. lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt F6 83 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt HT gt lt DLE gt lt ETX gt BE 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt HT gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt N UL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3E 7A lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt LF gt lt DLE gt lt ETX gt BE 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt LF gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt N
38. lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt F 7 NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 43 34 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt CR gt lt DLE gt lt ETX gt BC A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt CR gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt H8BHCD lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SO gt lt DLE gt lt ET
39. of each system and potential constraints while requesting for signal priority in real time applications 4 1 Wireless Communication Testing Wireless communication testing for Denso DSRC radios and Wi Fi module were tested at two different test sites East Franklin Avenue at 2274 Avenue and Como Avenue at 29 Avenue in Minneapolis A pair of data communication programs using User Datagram Protocol UDP were written in C language and running on both roadside and onboard embedded computers The onboard computer receives the vehicle location from the GPS receiver every 200 ms 5 Hz and sends vehicle ID passenger counts location priority request and other information to the roadside computer wirelessly The roadside equipment immediately returns the data string received from onboard computer Wireless communication latency is calculated from the time difference between the data string sent to RSE and received back on the onboard computer 4 1 1 DSRC Communication Latency As shown in Figure 4 1 the roadside equipment is placed at location A where latency testing begins along the East Franklin Avenue The onboard equipment is placed inside a passenger vehicle The onboard computer continuously sends out UDP data to the roadside unit through the Denso DSRC radio modem as the vehicle traverses from location A to B then turns around at B The test vehicle passes through location C and turns around again at location D then returns back to starting locatio
40. pulsating 1 30 Hz ground true logic input When the preempt link value in the PREEMPT MISCALLENAEOUS menu equals to the preempt command then a constant input actuation will place a call for low priority routine According to the Eagle SEPAC manual enabling the low priority routine will insert a delay of 500 milliseconds into the recognition of a standard preempt routine This delay will allow the traffic controller to determine whether the request is a low priority or preemption call When a low priority routine is enabled the preempt call for the same input is a pulse signal and the duration of the pulse signal must be longer than 1 second Preempt channel 5 was configured as low priority channel to accept inputs from the roadside computer HHH Ga 505 Bra Figure 2 15 Eagle EPAC 40 Traffic Signal Controller 2 4 2 Wiring Diagram of Priority Input There are several ways to initiate TSP request on the signal controller An external request from the digital input 1s the simplest way to initiate the request However there will be no TSP responses from the signal controller The RSE has no information whether the request was granted or not Another way to initiate the TSP request is to interface with the controller serial interface RS 232 or communicate through the NTCIP interface for example Los Angeles Metro TSP project as illustrated in Figure 2 16 TSP reugets were sent directly to the con
41. routers allow the communication The mediating gateway is typically a network address translation NAT device or a proxy server Routers by default will forward packets with RFC 1918 http tools ietf org html rfc1918 addresses Unlike public Internet routers that need additional configuration to discard these packets internal routers do not need any additional configuration to forward these packets Someone may argue that latency of data communication between the onboard system and the roadside system may increase significantly when introducing additional software or the NAT gateway However variation of the network latency plays a more critical role than the latency itself Latency can be compensated for realtime application as long as the wireless network is reliable Using the Minneapolis Wi Fi network for TSP application can certainly reduce cost by taking advantage of the existing infrastructure However availability of data bandwidth and quality of service concern of network reliability and data security need to be addressed when choosing the Wi Fi technology The DSRC radio is potentially good with excellent performance short range with fast data communication rate but the availability of DSRC is currently limited We certainly don t know whether there will be national rollout The UMN TSP system uses wireless technology to establish data communication between transit vehicles and roadside systems It is not limited to any particul
42. strPtr 0 i20 while 1 while nbytes read fd buffer BUFFER_SIZE gt 0 for i20 i lt nbytes i dataStr strPtr buffer i strPtr if buffer i n dataStr strPtr O terminate string strPtr 0 parseGPSStr dataStr end for end while end while 1 of readGPSStr routine void sendSerial int fd char text int num num write fd text strlen text send packet printf d bytes sent n num end of sendSerial int getSentencelD int sID 1 extract data from each parsed text field if stremp NMEA fields 0 GPGGA 0 sID GPGGA ID else if stremp NMEA fields 0 GPVTG 0 510 GPVTG 10 return sID end of getSentencelD int parseGPSField int sentencelD int field index double data data deg char int int data time t now struct tm local time switch sentencelD case GPGGA 10 update GPGGA sentence switch field index case 2 gt gps_mm 100 0 case 3 case 4 case 5 case 6 case 7 case 8 case 9 case 10 case 14 myGPS gt gpstime atof NMEA fields field index 1 myGPS gps hh floor myGPS gt gpstime 10000 0 myGPS gt gps_mm floor myGPS gt gpstime myGPS gt gps_hh 10000 0 100 0 myGPS gt gps_ss myGPS gt gpstime myGPS gt gps_hh 10000 0 myGPS now time 0 local_time localtime amp now myGPS
43. updated prepared by Advanced Traffic Management Systems Committee and Advanced Public Transportation Systems Committee of the ITS America Washington D C Jarmar Technologies JAMAR Hand held traffic data collector DB 400 Horsham PA http www jamartech com accessed November 1 2007 Kim W and Rilett L R 2005 An Improved Transit Signal Priority System for Networks With Nearside Bus Stops Transportation Research Board 84 Annual Meeting Compendium of Papers CD ROM Washington D C King County Department of Transportation 2002 An Evaluation of Transit Signal Priority in Aurora Avenue North Transit Speed and Reliability Program King County Department of Transportation King County WA Kittelson amp Associates Inc 2006 LADOT County Transit Signal Priority System Technical report Kittelson amp Associates Inc Portland OR Li M Wu G Li Y L Bu F Zhang W B 2007 Active Signal Priority for Light Rail Transit at Grade Crossings TRB 86th Annual Meeting Compendium of Papers CD ROM Washington D C Li M Y Zhou K Zhang W B Liu H and Tan C W 2005 Adaptive Transit Signal Priority on Actuated Signalized Corridors Transportation Research Board 84 Annual Meeting Compendium of Papers CD ROM Washington D C Liao C F Davis G A 2006 Bus Signal priority Based on GPS and Wireless Communications Phase I Simulation Study Final Report ITS Institute CTS University of M
44. usually granted after a preprogrammed time offset after detection Engineers have to adjust the detector location receiver line of sight and timing offset for each intersection in order to ensure its effectiveness These TSP strategies do not consider the bus s speed and its distance from intersection when determining the appropriate time to request signal priority The proposed study would like to incorporate the GPS AVL system on the buses in Minneapolis and develop a signal priority strategy based on the bus s timeliness with respect to its schedule number of passengers location and speed of a bus Wireless communications systems have made rapid progress and are commercially available Bus information e g speed location number of passengers bus ID can be transmitted wirelessly to a traffic controller or to a regional Traffic Management Center TMC in making decisions for signal priority There are several wireless communication systems installed on each bus under the current Metro Transit setup An 800 MHz Motorola digital voice radio is used for communication between bus driver and Transit Control Center TCC Another 800 MHz analog data radio is used to poll bus location and passenger count data every minute A Wireless Local Area Network WLAN 802 11x is also installed on the bus This is used to upload download files between the bus and the TCC central server when the bus is within the proximity of the transit garage 1 2 Research Obje
45. vehicle fare collection method and bus type Estimated passenger arrival rates will be used to forecast bus dwell time at each stop Based on the collected data we assume the passenger arrivals at each stop follow a Poisson distribution with an arrival rate A calculated from the mean of the collected passenger arrival rate A Poisson process subroutine was developed to generate numbers of passengers boarding and alighting at each stop during the simulation Bus dwell time at a bus stop for boarding can be estimated using the following equation D Ai f x 0 j zs fa T dos Eq 8 Where 15 is the bus dwell time for boarding at stop j A t is the passenger arrival rate for stop t J is the arrival time of bus at stop t j is the arrival time of bus k 1 at stop and T boarding 19 the average boarding time per passenger 3 3 Priority Acknowledgement Rules After receiving a signal priority request from a bus the signal controller has to determine whether or not to grant the request Only one bus will get the priority service if there are multiple requests at the same intersection from buses on different approaches The signal controller will ignore all bus priority requests if there is an emergency vehicle preemption request The signal controller will consider the following three components when determining which bus will receive the priority service 18 3 3 1 Priority Request Time Time Factor TF A
46. views or policy of the Intelligent Transportation Systems Institute or the University of Minnesota The authors the Intelligent Transportation Systems Institute the University of Minnesota and the U S Government do not endorse products or manufacturers Trade or manufacturers names appear herein solely because they are considered essential to this report ACKNOWLEDGEMENTS We would like to thank the Intelligent Transportation Systems ITS Institute and Center for Transportation Studies CTS University of Minnesota for supporting this project The ITS Institute is a federally funded program administrated through the Research amp Innovative Technology Administration RITA We also would like to recognize the following people and organizations for their invaluable assistance in making this research possible Bryan Newstrom at Intelligent Vehicle Laboratory Department of Mechanical Engineering for providing support on embedded Linux operating system e Intelligent Vehicle Laboratory Department of Mechanical Engineering for using its Denso DSRC radio modems e Minnesota Traffic Observatory Department of Civil Engineering for using the lab facility e Scott Tacheny Don Sobania and their electricians at the City of Minneapolis Department of Public Works for providing traffic data signal timing plan and numerous discussions and responses to our questions e Gary Nyberg Janet Hopper and John Levin at Metro Transit for providing
47. 0 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ACK gt lt DLE gt lt ETX gt BB 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ACK gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt NUL gt lt NUL gt 40 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 77 82 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt BEL gt lt DLE gt lt ETX gt BA lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt BEL gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 64 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt DF 71 lt DLE gt 30 lt EOT gt
48. 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SOH gt lt DLE gt lt ETX gt B9 A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt SOH gt lt NUL gt 78 lt NUL gt lt NUL gt lt NUL gt 96 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 2D 44 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt STX gt lt DLE gt lt ETX gt B9 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt STX gt lt NUL gt 96 lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt NUL gt lt NUL gt 40 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt A3 F7 lt DLE g
49. 415 432 Mirchandani P B Knyazyan A Head K L Wu W 2001 An Approach Towards the Integration of Bus Priority Traffic Adaptive Signal Control and Bus Information Scheduling Systems Computer Aided Scheduling of Public Transport Journal of Scheduling Springer Verlag Germany pp 319 334 Mirchandani P B Lucas D E 2004 Integrated Transit Priority and Rail Emergency Preemption in Real Time Traffic Adaptive Signal Control Journal of Intelligent Transportation Systems Technology Planning and Operations Vol 8 Issue 2 pp 101 115 http www informaworld com smpp content content a713904020 db all order page accessed October 1 2007 Rakha H Ahn K Collura J 2006 Transit Signal Priority Project Along Route 1 Lessons Learned Virginia Transportation Research Council Charlottesville VA VTRC 06 CR Saint Cloud Metropolitan Transit Commission 2000 Transit Priority Evaluation Report Final Report St Cloud MN Siemens Traffic Controls SCOOT Split Cycle Offset Optimisation Technique www scoot utc com accessed October 1 2007 Siemens Intelligent Transportation Systems 2002 SEPAC Actuated Signal Control Software User s manual http www itssiemens com en t nav228 html accessed October 1 2007 Siemens Intelligent Transportation Systems Eagle EPAC M50 Traffic Control Unit http www itssiemens com en u_nav2131 html accessed October 1 2007 Skabardonis A 2000 Control
50. 68 1 2 Modem 2 1 192 168 1 1 Figure 2 7 Wireless Communications Using the Ruckus Modem Since Minneapolis wireless network does not cover the University of Minnesota UMN campus area a pair of LinkSys http www linksys com Wireless N USB adapters as shown in Figure 2 8 was also used during the development phase to test the wireless communication systems using the University of Minnesota wireless network from the lab The RSE and OBE were each connected to a adapter to establish connections through the UMN wireless network as shown in Figure 2 9 USB wireless adapters are usually plug and play after installing the device drivers in Windows operation system However many vendors do not release specifications of the hardware or provide a Linux driver for their wireless network cards An NDISwrapper http ndiswrapper sourceforge net joomla open source project implements Windows kernel Application Programming Interface API and Network Driver Interface Specification NDIS API within Linux kernel A Windows driver for wireless network card is then linked to this implementation so that the driver runs natively as though it is in Windows without binary emulation With the NDISwrapper most miniPCI builtin PCI PCMCIA Cardbus only or USB wireless network cards work in Linux with x86 or x86 64 Although NDISwrapper is intended for wireless network cards other devices are known to work according the NDIS wrapper project website for example
51. 7 TW Vas AO 504994130 don Figure 1 Como and 29th Avenue Geometry Layout and Phase Assignment 1 A 2 Signal Timing Data 2 Phase Data Como 29th Avenue SOURCE Database File Edit View Device Help 6 5 X T ean Green fr Yellow Change Red Clearance Vehicle Basic Timing A Vehicle Density Timing Pedestrian Timing A General Control For Help press F1 2 Figure 2 Signal Timing Data from MarcNX Software 2 IntersectionLayout Data Como 29th Avenue SOURCE Database File Edit Help su ane window esL et eer wo wer wer meL mer mer sou ser son 0 0 0 0 0 0 0 0 0 0 0 0 Number of Lanes Shared Lane 0 0 0 0 0 0 0 0 Saturation Flow vphpl 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 1900 Lane Width ft 12 12 12 12 12 12 12 12 12 12 12 Grade 35 0 0 0 8 Storage Lane ft f i 1 Storage Lanes Protected Phase Permissive Phase Street Name i gt i 4 gt gt Intersection Layout Volume Detector 1 12 Volume Detector 13 24 Location For Help press F1 2 Figure A 3 Intersection Data from MarcNX Software A 2 APPENDIX B TRAFFIC VOLUME AT COMO 6 2978 AVE The following are the traffic counts collected by the City of Minneapolis in 2006 at Como and 29 Avenue Table B 1 Traffic
52. 7 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt AB C1 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 28 lt DLE gt lt ETX gt A6 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 28 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 40 7F lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt
53. 9999 9 meters Geoidal height 999 9 to 9999 9 meters Null Differential GPS Null Differential Reference Station ID G 2 2 Track Made Good and Ground Speed VTG Table G 2 VTG Sentence GPVTG lt 1 gt T lt 2 gt M lt 3 gt N lt 4 gt K lt 5 gt hh lt CR gt lt LF gt True course over ground GPS 18 PC and 000 to 359 degrees GPS 18 5Hz 000 0 to 359 0 degrees leading zeros will be transmitted Magnetic course over ground 000 to 359 degrees GPS 18 5Hz 000 0 to 359 0 degrees leading zeros will be transmitted Speed over ground GPS 18 PC and LVC 000 0 to 999 9 knots GPS 18 5Hz 000 00 to 999 99 knots leading zeros will be transmitted Speed over ground GPS 18 PC and LVC 0000 0 to 1851 8 kilometers per hour GPS 18 5Hz 0000 00 to 1851 89 leading zeros will be transmitted Mode indicator only output if NMEA 0183 version 2 30 active A Autonomous D Differential E Estimated N Data not valid G 2 Garmin GPS Display GPGG4 035857 4 4507 34025 N 03330 36447 211 1 8 297 5 30 8 GPWTG 318 3 1 316 7 M 000 01 N 0000 03 K 76 Figure G 2 GPS Receiver Test Interface G 3 2 3 GPS Test Interface GUI Source Code Imports System IO Public Class GpsDisplay Inherits System Windows Forms Form Dim dataRcvd DATA SIZE 2 As Byte Public UTC str As String Dim NMEA type Lat str NS str Long str EW str As String Dim PFix str SatUsed str Alt str AltUnit s
54. C4 gt lt ACK gt lt EOT gt lt DLE gt lt ETX gt BA F2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt EOT gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 22 5C lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ENQ gt lt DLE gt lt ETX gt BB 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ENQ gt lt NUL gt 96 lt NUL gt lt NUL gt lt NUL gt 96 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt H 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 32 B7 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 3
55. C4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 5 81 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt FF gt lt DLE gt lt ETX gt BD 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt FF gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 43 34 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt CR gt lt DLE gt lt ETX gt BC A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt CR gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt
56. Counts at Como and 29 Avenue From North From East From South From West 5 T 1 3 3 9 y 6 2 07 00 AM 3 28 9 8 2 0 0 1 07 15 3 5 8 12 2 0 D 1 07 30 AM 3 11 4 3 0 2 1 07 45 5 12 5 13 3 1 2 4 26 36 4 5 1 5 3 3 5 3 2 D 0 2 2 1 2 0 1 5 3 5 1 0 4 0 0 0 1 z 2 0 3 0 0 6 43 9 25 8 1 1 0 1 4 7 2 5 4 6 D 1 5 5 5 5 7 2 4 3 3 1 4 1 gt e al ww un winwos oo wa mo www uw ooo Nocon wono jos ur Sink woowo Bi ON vn oo on an Blua oonn mjo ane From East From South From West L sume ugs ew PE A Peds Rignt Tnru 605 Right LemR Peds int Total in in ot 10 12 sol ol 1 2 1 157 5 1 139 6 5 D 0 2 0 4 7 1 1 3 0 0 3 0 1 2 1 0 0 1 0 2 7 16 2 27 7 1 2 3 4 3 0 2 1 4 0 3 0 2 3 4 0 2 0 1 5 5 6 4 6 B 12 2 16 0 1 3 2 2 0 5 2 3 2 4 3 5 1 3 4 1 5 2 3 4 2 B 7 3 5 0 4 10 32 7 1 7 1 2 2 2 3 2 D 3 0 0 0 1 0 1 D 0 0 0 0 0 0 0 D 19 5 0 0 1 1 Total 1 29 28 1 44 51 1 7 25 27 2 3 4 58 4 295 05 00 PM 4 13 1 2 0 0 1 20 8 2 169 05 15 2 4 1 3 3 1 23 3 3 121 05 30 PM 2 2 3 5 3 0 0 1 31 1 1 102 20 5 3 6 30 27 4 0 6 2 9 2 0 3 4 0
57. DLE gt lt E TX gt F2 AB lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 23 lt DLE gt lt ETX gt A1 lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 23 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt lt RS gt 76 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 24 lt DLE gt lt ETX gt A3 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 24 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt
58. ITS Intelligent Transportation Systems A Bus Signal Priority System Using Automatic Vehicle Location Global Position Systems and Wireless Communication Systems Final Report Prepared by Chen Fu Liao Gary A Davis Priya lyer Department of Civil Engineering University of Minnesota CTS 08 18 CENTER FOR TRANSPORTATION STUDIES UNIVERSITY OF MINNESOTA Technical Report Documentation Page 1 Report No 2 3 Recipients Accession No CTS 08 18 4 Title and Subtitle 5 Report Date A Bus Signal Priority System Using Automatic Vehicle Location Global Position Systems and Wireless Communication Systems 7 Author s 8 Performing Organization Report No 9 Performing Organization Name and Address 10 Project Task Work Unit No Department of Civil Engineering CTS project 2007089 University of Minnesota 11 Contract C or Grant G No 500 Pillsbury Drive S E Minneapolis MN 55455 0116 12 Sponsoring Organization Name and Address 13 Type of Report and Period Covered Intelligent Transportation Systems Institute Final Report University of Minnesota 14 Sponsoring Agency Code 200 Transportation and Safety Building 511 Washington Ave SE Minneapolis Minnesota 55455 15 Supplementary Notes http www cts umn edu Publications ResearchReports 16 Abstract Limit 250 words Current signal priority strategies implemented in various US cities mostly utilize s
59. N radio that are already installed on the Metro Transit buses We plan to identify potential software or firmware changes that are needed to allow wireless communications between the bus onboard computer and other roadside equipment using the 802 11x wireless communication protocols Unprotected Wi Fi networks pose multiple threats to the transit system Data encryption access authentication and dedicated Virtual Private Networks VPNs will be investigated and evaluated as potential solutions to protect the transit wireless network We also would like develop a communication framework between the buses and the roadside infrastructure for ITS applications that can potentially be deployed by Metro Transit region wide Our intent is to investigate the feasibility and reliability of implementing a vehicle to infrastructure wireless communication framework for the various intelligent transit applications described in the study Minnesota is one of five communities nationwide to receive funding through the U S Department of Transportation s Urban Partnership Agreement UPA program to develop strategies and to implement and deploy applications to reduce traffic congestions in the Twin Cities As part of the UPA program Metro Transit is working with consultants to design concept of operation to provide transit signal priority TSP along Central or Nicollet Avenue running in parallel with I 35W The idea of the wireless based TSP approach is to utilize as much a
60. S Text 5 str If NS str IndexOf S gt 0 Then gpsLat 1 gpsLat End If Case 5 Longitude Long str receivedSentence Substring st idx en idx st idx tmpStr Long str Substring 0 3 gpsLong Convert2Double tmpStr tmpStr Long str Substring 3 gpsLong Convert2Double tmpStr 60 txtLong Text Long str Substring 0 3 Long str Substring 3 Case 6 E W indicator EW str receivedSentence Substring st idx idx st idx IbIEW Text EW str If EW_str IndexOf W gt 0 Then gpsLong 1 gpsLong End If Case 7 Positioin Fix PFix_str receivedSentence Substring st_idx en_idx st_idx Select Case PFix_str Case 0 txtPFix ForeColor Color Red txtPFix Text Invalid Case 1 txtPFix ForeColor Color Blue txtPFix Text Valid SPS Case 2 txtPFix ForeColor Color Blue txtPFix Text Valid DGPS Case 3 txtPFix ForeColor Color Blue txtPFix Text Valid PPS End Select Case 8 Satellite used SatUsed str receivedSentence Substring st idx idx st idx txtSatUsed Text SatUsed str Case 9 HDOP Horizontal dilution of precision Case 10 alittude Alt str receivedSentence Substring st idx en idx 5 idx txtAlt Text Alt str Case 11 altitude unit AltUnit str receivedSentence Substring st idx en idx st idx IbIAItUnit Text AltUnit str End Select End If Next i Elself NMEA type IndexOf GPVTG gt 0 Then Timer2 Enabled True GPVTG str received
61. SP request 7 sent at 02 47 8 A Vehicle arrives at intersection TSP request terminated T T T T T T 02 29 8 02 384 02 47 0 02 55 7 03 04 3 03 13 0 03 21 6 03 30 2 03 38 9 Time mm ss s Cn E ee Main Street Traffic Light Figure 5 8 Vehicle Distance to Intersection and DSRC Wireless Coverage Westbound 33 Vehicle speed versus time for the early green scenario in the westbound approach was analyzed as shown in Figure 5 9 The test vehicle was traveling with the wireless communication connection from 02 38 to 03 15 duration of 37 seconds The vehicle was travelling toward the signalized intersection when the light is red Signal priority was requested when the test vehicle began to slow down due to the queue in front of the test vehicle Traffic controller acknowledged the priority request and provided an early green around 02 59 After receiving the green light on the main approach the speed of the test vehicle increased as the queue in front began to discharge Test vehicle left the intersection around 03 04 at speed around 17 MPH The average wireless data communication latency is about 4 3 ms for the westbound testing using the DSRC radio Speed MPH TSP request sentat 02 47 8 20 1 25 Vehicle arrives atNntersection 10 DSRC Wireless Communication Established 0 m T 7 T T 02 29 8 02 38 4 02 47 0 02 55 7 03 04 3 03 13 0 03 21 6 03 30 2 03 38 9 Time mm ss s
62. Sentence End If sentence type txtLongDeg Text Convert ToString Math Round gpsLong 1000000 1000000 txtLatDeg Text Convert ToString Math Round gpsLat 1000000 1000000 convert lat long to XY gpsLatLong setLatLong gpsLat gpsLong SPCS XY convert2XY gpsLatLong txtPosX Text Convert ToString Math Round SPCS XY getX 100 100 txtPosY Text Convert ToString Math Round SPCS XY getY 100 100 Catch ie As Exception txtError Text ie Message tmpStr vbNewLine End Try Next sent_i End Sub Public Function Convert2Double ByVal str As String As Double Dim retVal As Double retVal 0 If IsNothing str Then Return 0 End If If str Length gt 0 Then retVal Convert ToDouble str End If Return retVal End Function Private Sub btnExit_Click ByVal sender As System Object ByVal e As System EventArgs Handles btnExit Click recTimer Enabled False Timer2 Enabled False Timer1 Enabled False moRS232 Close Application Exit End Sub Private Sub GpsDisplay_Closing ByVal sender As Object ByVal e As System ComponentModel CancelEventArgs Handles MyBase Closing moRS232 Close Application Exit End Sub Private Sub NMEAStr_Box_TextChanged ByVal sender As System Object ByVal e As System EventArgs Handles NMEAStr_Box TextChanged End Sub convert lat long to XY Public Function convert2XY ByVal myLatLong As Point2D As Point2D Dim sin phiO sin phi As Double Dim gamma Ln1 Ln2 R Q As Double
63. Substring 3 gpsLong Convert2Double tmpStr 60 txtLong Text Long str Substring 0 3 Case 7 E W indicator EW str receivedSentence Substring st idx idx st idx IbIEW Text str If EW_str IndexOf W gt 0 Then gpsLong 1 gpsLong End If Case 8 Speed Knot str receivedSentence Substring st idx en idx 51 idx vehSpeed Convert2Double Knot str 1 150779448 convert from knot to MPH txtSpeed Text Convert ToString Convert ToUInt16 vehSpeed Case 9 course Heading_str receivedSentence Substring st_idx en_idx st_idx txtHeading Text Heading_str ww Long_str Substring 3 End Select End If Next i Elself NMEA type IndexOf GPGGA gt 0 Then Fori 2To11 st_idx en_idx 1 en idx receivedSentence IndexOf st_idx If en idx gt 0 Then Select Casei Case 1 sentence ID NMEA type receivedSentence Substring st idx st idx Case 2 UTC time UTC str receivedSentence Substring st idx en_idx st_idx lbITime Text UTC str Substring 0 2 UTC str Substring 2 2 UTC_str Substring 4 Case 3 latitude Lat_str receivedSentence Substring st_idx en_idx st_idx tmpStr Lat str Substring 0 2 gpsLat Convert2Double tmpStr tmpStr Lat_str Substring 2 gpsLat Convert2Double tmpStr 60 txtLat Text Lat_str Substring 0 2 Lat str Substring 2 Case 4 N S indicator NS str receivedSentence Substring st idx idx st idx IbIN
64. UL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 70 3A lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 26 lt DLE gt lt ETX gt A2 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 26 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 47 lt FS gt lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 27 lt DLE gt lt ETX gt A3 C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 2
65. UL gt lt NUL gt lt NUL gt lt FF gt 2F AB lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C6 D2 gt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 25 D1 lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3F 29 22c22 lt DLE gt lt STX gt lt ACK gt lt NUL gt lt NUL gt 46 lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 5C A2 gt lt DLE gt lt STX gt lt ACK gt lt NUL gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt B7 F3
66. UL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 20 78 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt VT gt lt DLE gt lt ETX gt BF lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt VT gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt E5 81 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt FF gt lt DLE gt lt ETX gt BD 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt FF gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt
67. UL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 77 82 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt BEL gt lt DLE gt lt ETX gt BA lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt BEL gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 64 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt DF 71 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt BS gt lt DLE gt lt ETX gt HBFHF2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt BS gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt
68. UL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 47 lt FS gt lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 27 lt DLE gt lt ETX gt A3 C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 27 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt AB C1 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 28 lt DLE gt lt ETX gt A6 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 28 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt
69. X gt BC 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt SO gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt f28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 98 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt SI gt lt DLE gt lt ETX gt BD C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt SI gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 50 36 lt DLE g
70. _cflag amp CSTOPB options c_cflag amp CSIZE options c_cflag CS8 tcsetattr fd TCSANOW amp options H 2 Bus Roadside Unit Sample Source Code bus rsu udp c This is the roadside unit RSU interface to communicate with bus onboard unit OBU through radio to get bus GPS AVL data and process signal priority request to traffic signal controller Created on July 30 2007 5 36 PM Copyright Regents of the University of Minnesota All rights reserved pr Chen Fu Liao Sr Systems Engineer Minnesota Traffic Observatory MTO ITS Institute CTS Department of Civil Engineering University of Minnesota 500 Pillsbury Drive SE Minneapolis MN 55455 include lt stdio h gt include lt stdlib h gt include lt unistd h gt include lt errno h gt include lt string h gt include lt sys types h gt include lt sys socket h gt include lt netinet in h gt include lt arpa inet h gt include lt sys wait h gt include lt signal h gt include bus_rsu h int main int argc char argv thread 1 communicate with OBU client pthread t thread1 char message1 UDPserver int ireti Create independent threads each of which will execute function iret pthread create amp thread1 NULL serverComm void message1 pthread join thread1 NULL return 0 end of main void serverComm void data listen on sock fd new connec
71. a bus receives green signal extension along Como Avenue Figure 5 1 Bus Receives Signal Priority 5 1 Analyze Data Collected From Onboard Equipment Vehicle location speed time and priority request status were recorded while the test vehicle was traveling from the 27 to 315 Avenue along the Como Avenue As shown in Figure 5 2 each red dot represents one wireless communication string recorded from onboard computer Signal priority data string was collected at every 200 milliseconds since the Garmin GPS receiver can only provide position update at 5 Hz when the onboard equipment establishes communication with the roadside equipment The onboard equipment will record GPS data string after one second of timeout period if the wireless communication link was lost in the vehicular environment 5 1 1 Signal Priority Request for Green Extension Signal priority request for green extension on the main street Como Avenue was analyzed in this experiment In Figure 5 2 the vehicle started at location A outside the coverage range of wireless communications The DSRC wireless communication was established between location B and F However during this particular testing there were communication gaps nearby location C D and E where the communication between the vehicle and the roadside equipment was lost ocassionally Figure 5 3 shows the distance from the test vehicle to the intersection over test period The test vehicle was initially idling at about 180 m
72. accessed October 1 2007 Transport Simulation Systems 2002 GETRAM Extensions Version 4 1 User s Manual TSS Barcelona Spain 42 Wadjas Y Furth P G 2003 Transit Signal priority Along Arterials Using Advanced Detection Transportation Research Record No 1856 pp 220 230 Wischhof L Ebner A Rohling H Lott M Hafmann R 2003 Adaptive Broadcast for Travel and Traffic Information Distribution Based on Inter Vehicle Communication Proc IEEE Vehicular Technology Conference VTC 2003 Orlando FL Wu H Lee J Hunter M Fujimoto R Guensler R Ko J 2005 Efficiency of Simulating Vehicle Vehicle Message Propagation in Atlanta Georgia I 75 Corridor Transportation Research Record No 1910 pp 82 89 Xu Q Hedrick K Sengupta R VanderWerf J 2002 Effects of Vehicle vehicle roadside vehicle Communication on Adaptive Cruise Controlled Highway Systems Proceedings of IEEE 56th Vehicular Technology Conference Birmingham AL Volume 2 pp 1249 1253 Zhang J 2003 Zero Public Infrastructure Vehicle Based Traffic Information System Transportation Research Board 82 Annual Meeting Compendium of Papers CD ROM Washington D C Zheng J Wang Y Liu H Hallenbeck M E 2007 Modeling Impact of Near Side Bus Stop on Transit Delays at Transit Signal Priority Enabled Intersections TRB 86th Annual Meeting Compendium of Papers CD ROM Washington D C 43 APPENDIX
73. affic signals SPLIT McLeod suggested that differential conditional priority strategies e g granting priority for lateness give the best results as these provide a good balance between travel time and passenger waiting time Furth and Mueller 2000 conducted a field study with three priority conditions no priority absolute priority and conditional priority at a transit route in the Netherlands The study found absolute priority caused large delays to other traffic while conditional priority caused little if any additional delay Dion and Rakha 2005 developed a simulation approach to integrate TSP within an adaptive traffic control system They evaluate three different signal control scenarios and found adaptive signal control reduced negative impacts on general traffic while providing signal priority to buses Recently Mirchandani amp Lucas 2004 developed a Categorized Arrival based Phase Reoptimization at Intersection CAPRI strategy that integrates transit signal priority within a real time traffic adaptive signal control system called RHODES Real time Hierarchical Optimized Distributed Effective System 2001 Weighted bus and phase constrained approaches were developed for providing transit priority through the RHODES CAPRI framework Mirchandani et al 2001 proposed a hierarchical optimization approach where traffic signals are determined by considering delays of all vehicles on the network as well as bus passenger counts a
74. apolis Wi Fi network currently does not offer static IP assignment for each subscriber This could cause communication issues for TSP applications whenever a unit has to recycle power USI wireless will need to modify the network connection settings in order to allow static IP address assignment and direct wireless communications between the RSE and OBE in the vehicular environment External IP 206 55 182 229 af External IP 206 55 182 230 Minneapolis Wi Fi Sd an an Modem 1 92 168 1 2 3 Party Modem 2 192 168 1 1 Application Figure 5 12 Wireless Data Communication through a 3rd Party Application 36 6 FUTURE WORK We would like to meet with USI wireless to pursue possible modification of network access with special IP assignment or other options for wireless connectin to OBE and RSE The phase III wireless TSP project was awarded by ITS institute Phase III project proposed to instrument four to six intersections with RSEs and install OBEs on a few buses with interface to the bus AVL GPS system The proposed phase III research project will evaluate the impact of TSP deployment along a selected corridor We would like to evaluate the tSP performance along a corridor as compared to the results from other deployments e g LA Chicago etc We will invtigate the reliability and explore the limitation of our TSP system We plan to examine and evaluate the existing transit control systems SMARTCoM AVL system and WLA
75. ar wireless technology This report documents the development verification and validation of the embedded signal priority prototype systems field testing results and limitations of using the Minneapolis Wi Fi network for TSP Detail documentations of the system design and integration are included in the appendices 1 INTRODUCTION Transit Signal Priority TSP for transit has been studied and proposed as an efficient way to improve transit travel amp operation Bus signal priority has been implemented in several US cities to improve schedule adherence reduce transit operation costs and improve customer ride quality Signal priority strategies have helped reduce the transit travel time delay as discussed in the literature ITSA 2002 but the transit travel time reduction varies considerably across studies Collura et al 2003 Signal priority and preemption are often used synonymously however they are different processes Signal preemption is traditionally used for emergency vehicles EV or at railroad crossing Preemption interrupts normal intersection signal process to provide high priority for special events Signal priority modifies the normal signal operation in order to accommodate better service for transit vehicles ITSA 2004 1 1 Background Current signal priority strategies implemented in various US cities mostly utilized sensors to detect buses at a fixed or at a preset distance away from the intersection Signal priority is
76. bedded system interfaces with the GPS and wireless communication systems to transmit vehicle location and other information for example vehicle ID route ID passenger counts door opening status and so on to the roadside equipment The RSE continuously monitors the vehicle location when it travels within the range of the wireless communication and then generates a signal priority request to traffic signal controller as needed Field testing results show that the test vehicle successfully submitted a signal priority request through the wireless communication as it is traveling toward the intersection instrumented with roadside equipment The test vehicle was initially traveling from a location outside the communication range of the DSRC WAVE radios As soon as the vehicle moved within the wireless communication range the adaptive signal priority algorithm began to monitor the location and speed of the test vehicle and submited a request for priority through the roadside interface to the signal controller when the vehicle was ready to enter the intersection The Eagle EPAC traffic signal controller is capable of providing green extension or red truncation or early green to the qualified or authenticated vehicle as it is approaching the intersection The signal priority request is dropped when the test vehicle passes the intersection or when the duration of priority call exceeds the maximum call setting We also tested our signal priority systems using th
77. bytes read fd buffer 255 gt 0 printf d bytes received n nbytes for i20 i lt nbytes i dataStr strPtr buffer i strPtr if buffer i n printf Data received s n dataStr strPtr 0 for while y while 1 else if argc 1 1 debug testing char testStr strepy testStr GPGGA 053856 0 4507 34256 N 09330 37989 W 1 05 2 5 283 4 M 30 8 M 6F Iprintf test str s n testStr parseGPSStr testStr printf n strepy testStr GPVTG 317 8 T 316 1 M 000 24 N 0000 45 K 71 Iprintf test str s n testStr parseGPSStr testStr printf loop here if return 0 end of main void clientComm void data char buf BUFFER SIZE int num char while 1 infinite loop num char sprintf buf d d 02d 02d 04 1f lf lf golf BUS ID COUNT myGPS gps hh myGPS gps mm myGPS 9ps ss myGPS cartesian x myGPS cartesian y myGPS gt speed send2RSU buf 128 101 111 119 msleep 20 end of while end of clientComm int msleep unsigned long milisec struct timespec req 0 time t sec int milisec 1000 milisec milisec sec 1000 reg tv sec sec req tv_nsec milisec 1000000L while nanosleep amp req amp req 1 continue return 1 void readGPSStr void data int nbytes 0 char dataStr BUFFER_SIZE char buffer BUFFER SIZE int
78. cation from westbound approach was analyzed in this experiment In Figure 5 7 the vehicle started at location A The DSRC wireless communication was established from location A to C However during this particular testing there were communication gaps nearby location B where the communication link between the vehicle and the roadside equipment was lost ocassionally 32 Distance meter Figure 5 7 Recorded GPS Data Point Along Como Ave SE Westbound Figure 5 8 shows the distance from the test vehicle to the intersection versus time The test vehicle was initially idling at about 175 meters upstream away from the intersection at location A The vehicle moved within the wireless communication range at 02 38 when the adaptive signal priority algorithm began monitoring the location and speed of the test vehicle Priority request was sent at around 02 48 to the roadside equipment to request for early green as the vehicle approaching the intersection The test vehicle arrived at the intersection at around 03 04 as illustrated in Figure 5 8 The vehicle was intentionally started when the traffic signal on Como Avenue became red The DSRC wireless communication was established from 02 38 to 03 15 Signal light on Como Avenue was red as the test vehicle approaching the intersection Signal priority was requested through the wireless communication interface at 02 48 e GPS Data 250 200 150 __ O NSO 100 T
79. cle A pair of DSRC WAVE radios and 802 11x wireless modems were used for testing wireless communications between the onboard equipment OBE and the roadside equipment RSE Communication coverage and latency were measured for both DSRC and 802 11x Wi Fi adapters to better understand the performance of each system and the potential constraints while requesting for signal priority in real time applications The performance evaluation of the wireless communication using the Denso DSRC radios and Wi Fi module were tested at two different test sites East Franklin Avenue at 22 Avenue and Como Avenue at 29 Avenue in Minneapolis The DSRC system was tested at both test sites The wireless performance testing using the Minneaplis Wi Fi network was performed at Franklin test site due to the USI wireless access point router was not yet installed at the Como test site A pair of data communication programs using User Datagram Protocol UDP were written in C language and running in both roadside and onboard embedded computers Signal priority request output on the roadside equipment was connected to a pre emption input channel on the signal controller through wirings in the controller cabinet Program of the traffic controller was also configured and activated to accept external pre emption inputs The traffic signal controller was programmed by the City of Minneapolis traffic engineer to specify corresponding delay dwell maximum call and extension time Develo
80. ctives We would like to provide effective signal priority to buses with minimal impact on other traffic using the already equipped GPS AVL system on the bus The GPS system offers better information regarding bus trajectory than the presence detection sensors previously used while requesting for traffic signal priority Our objective is to investigate the performance of GPS AVL and deploy a wireless based adaptive signal priority strategy to provide reliable and efficient bus transit services with minimal impact on traffic flow Metro Transit buses currently equip with 800MHz data and voice radio and 802 11b g systems We would like to utilize the existing systems with little or no additional hardware installation on the buses for signal priority or other transit related ITS applications Communication with the roadside unit e g traffic controller for signal priority can later be established using the DSRC Dedicated Short Range Communication 802 11p protocol for wireless access in vehicular environment after the implementation and deployment of the VII initiatives The improved transit services will hopefully make the transit system more attractive to the public and increase ridership Simulation studies and field data collection were conducted to estimate changes in bus travel time delay as well as potential impact on other traffic 1 3 Literature Review The vision of the Vehicle Infrastructure Integration VII is to deploy a nationwide communicat
81. data input and monitoring in Hexadecimal Decimal Octal Binary and ASCII formats It also allows user to change or monitor RS 232 s line states Serial Port Monitor http www aggsoft com serial port monitor htm 232 Analyzer for sending the commands http www 232analyzer com 232default htm Here is the Hex data for the above communication along with the difference in the packet content F 1 Hex Dump for Phase Value of Six lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt 2F lt DLE gt lt ETX gt 5C 31 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 25 D1 lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3F 29 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt 2F lt DLE gt lt ETX gt lt ESC gt 69 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt 2F lt NUL gt lt DC4 gt 33 31 33 lt DC1 gt 5C 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt FF gt 25 D1 lt SOH gt 39 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3F 29 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt NUL gt lt DLE gt lt ETX gt B8 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt
82. e 5 12 both OBE and RSE receive dynamic IP addresses assigned under a private network for example IP 192 168 1 xxx connected to the wireless modems or adapters OBE and RSE reside in their own intranet as configured by the Wi Fi network server The OBE or RSE can freely communicate to the world through the Minneapolis Wi Fi network However the OBE cannot communicate with the RSE directly through the Wi Fi network due to security settings from the USI wireless servers We also investigated other options as recommended by USI wireless to use port forwarding and Network Address Translation NAT for wireless communications between OBE and RSE Because both the onboard and roadside computers reside with their own private domain the NAT settings configured within each Ruckus modem only allow intranet communication within the private domain The translated network address cannot pass though the barriers imposed by the DHCP settings of the USI wireless servers and modem settings USI wireless technical support later confirmed that the wireless communication between two clients within their network was not possible under the current network configuration We were then advised by the USI wireless to use third party software to achieve communications between our onboard and roadside equipment The data communication latency might be increased significantly when introducing additional software for wireless communication through the USI wireless network The Minne
83. e Minneapolis Wi Fi network In 2006 the City of Minneapolis signed a 10 year contract with USI Wireless of Minnetonka http www usiwireless com to provide city wide wireless broadband technology According to the City of Minneapolis the Minneapolis wireless network will cover all 59 square miles of Minneapolis providing residents businesses and visitors with wireless broadband access anywhere in the city The network will allow the city to deliver services more efficiently and effectively However the current settings and configuration of the Minneapolis Wi Fi network would not allow direct TCP UDP communications through their Wi Fi network between the OBE and RSE Both OBE and RSE can receive dynamic IP addresses assigned under the private network within the intranet connected to the wireless modems or adapters The OBE or RSE can freely communicate to the Internet through the Minneapolis Wi Fi network individually However the OBE cannot communicate with the RSE directly through the Wi Fi network due to security settings on the servers of USI wireless network We were advised by the USI wireless technical support to use third party software to communicate between our onboard and roadside equipment through Minneapolis Wi Fi network If a device on a private network needs to communicate with other networks a mediating gateway is needed to ensure that the outside network is presented with an address that 15 real or publicly reachable so that Internet
84. ed in Figure C 3 Como Ave and 29th Minneapolis R104 Digitall O P Cabinet Relay Board PRE EMPT IN5 579B Disconnect 579B from 600 24 VDC 599 Figure C 3 Connect Relay Output to Controller Cabinet C 3 JUMPER 1 TO 8 1 1 2 3 2 npe 2 2 3 3 2 z a 1 4 7 1 npu 5 2 1 Input 6 2 3 1 npu 2 2 1 npu 8 E 3 12U OUTPUT COMMON 54 OUTPUT L Buerd 2 0 Akb sss Selection DDR 240H OFF OFF DDR 260H OFF DOR 280H OFF ON DDR ON ON mera Impr Univ age Selertion DIGITRL INPUTS 5 Inu Seren Ter Junper B 4 5U Irputl JN OFF 10 150 Input OFF ON 24 280 Irput OFF OFF OFF Other a imere Digital Inputs are not rity Sensitive input signal tbe ted to terminais and 3 JUMPER 18 TO m LS JIGITAL OUTPUTS a aci Figure C 4 R104 Digital I O Relay Board Layout Tri M Engineering R104 88 User Guide C 4 Instructions to Build Debian Linux Kernel 1 Install Debian Linux on a development PC 2 apt cache search debootstrap apt cache install debootstrap 3 cd debian bus run buildroot hud build kernel image script 4 edit files after finished without error edit vim device
85. ed in the RSE to determine which phase and in what direction will the transit vehicle need signal priority The standard NEMA phase assignment for a main street in east west direction is shown in Figure 2 18 Sample priority phase selections and configuration 15 shown in Table 2 1 where the I O channels and priority inputs are specified 8 PHASING DIAGRAM Figure 2 18 NEMA Phase Assignments 14 Table 2 1 Priority Phase Selections and Configuration 15 3 ADAPTIVE TRANSIT SIGNAL PRIORITY STRATEGY To illustrate our priority strategy consider a simple eastbound westbound corridor as shown in Figure 3 1 For a bus approached a bus stop or signalized intersection there are basically two scenarios a nearside bus stop or a far side bus stop For the nearside bus stop a bus will stop for boarding alighting before passing the signalized intersection as illustrated in Figure 3 1 by the eastbound bus approaching stop j and intersection i Estimated bus dwell time at the nearside bus stop needs to be considered by the signal controller to provide signal priority to the bus in a timely manner For the far side bus stop a bus passes through the intersection first before its arrival at the stop see Figure 3 1 westbound bus approaching intersection i and bus stop k Bus travel time to the intersection needs to be considered when providing priority Westbound 60 x Bus Stop Bus Stop k Bus Stop k
86. ehicle Wireless Communication Protocols for Enhancing Highway Traffic Safety IEEE Communications Magazine Volume 44 Issue 1 pp 74 82 B hm M Pfliegl R Fr tscher A 2008 Wireless Infrastructure To Vehicle Communication Technologies to Increase Road Safety Along Motorways Transportation Research Board 87 Annual Meeting Compendium of Papers CD ROM Washington D C Bretherton R D Hounsell N B Radia B 1996 Public Transport Priority in SCOOT Proceedings of the 3 Annual World Congress on ITS Systems Orlando FL Collura J Rakha H and Gifford J 2003 Guidelines for the Planning and Development of Emergency Vehicle Preemption and Transit Priority Strategies Prepared by the Virginia Tech Transportation Institute Blacksburg VA and George Mason University School of Public Policy Arlington VA Crout D T 2005 Evaluation of Transit Signal Priority at the Tri County Metropolitan Transportation District of Oregon TriMet Proceedings of the 12 Annual World Congress on ITS Systems Nov 6 10 San Francisco CA Dion F Rakha H 2005 Integration of Transit Signal Priority Within Adaptive Traffic Control Systems Transportation Research Board 84 Annual Meeting Compendium of Papers CD ROM Washington D C Farradyne P B 2005 VII Architecture and Functional Requirements Version 1 1 U S Department of Transportation www vehicle infrastructure org documents VH 20Architecture 20vers
87. en 1 29 5 1 2 Eastbound Signal Priority Request for Early Green Red Truncation sess 31 5 1 3 Westbound Signal Priority Request for Early Green Red 32 5 2 Phasing and Timing Information from Signal Controller 2 34 5 3 Wireless Connections a Cerne Matte oret eter vasa Adan 35 5 4 Minneapolis Wireless Network esessesseeseeeeeesee 36 6 F t re 37 7 Summary and 5 0 11 38 IRE IIT RN 40 Appendix A Signal Phasing and Timing Information of Como amp 29 Ave Appendix Traffic Volume at Como amp 29 Ave Appendix Embedded Computer Systems Appendix Bus Route 3 Trip Data Appendix Wireless Devices Appendix F Serial Communication with the EPAC M40 Traffic Controller Appendix G Garmin GPS Receiver Appendix H Sample Source Code Appendix I Indemnity Letter LIST OF TABLES Table 2 1 Priority Phase Selections and Configuration cccccccescesscessceesceeeeeeseeeseeeseecseecsaecaeenseenseeeaeee 15 Table B 1 Traffic Counts at Como and 29 tette tentent B 1 Table D 1 Bus Route 3 Trip D 1 Table G 1 GGA Sentence 1 211 2 0 00000000000000 G 2 Ei AE VAALEAA E EEE
88. ensors to detect buses at a fixed or preset distance away from an intersection Traditional presence detection systems ideally designed for emergency vehicles usually send signal priority request after a preprogrammed time offset as soon as transit vehicles were detected without the consideration of bus readiness The objective of this study is to integrate the already equipped Global Positioning System Automated Vehicle Location GPS AVL system on the buses in Minneapolis and develop an adaptive signal priority system that could consider the bus schedule adherence its number of passengers location and speed Buses can communicate with intersection signal controllers using wireless technology to request for signal priority Similar setup can also be utilized for other transit related Intelligent Transportation Systems ITS applications The City of Minneapolis recently deployed wireless technology to provide residents businesses and visitors with wireless broadband access anywhere in the city Communication with the roadside unit e g traffic controller for signal priority may be established using the readily available 802 11x WLAN or the Dedicated Short Range Communication DSRC 802 11p protocol currently under development for wireless access in vehicular environment This report documents the development verification and validation of the embedded signal priority prototype systems field testing results and limitations of using the City of Minneapo
89. environment A set of PC 104 stand alone Single Board Computer SBC was selected for the embedded system development Additional I O modules were integrated to the embedded system to perform data communication between traffic signal controller and roadside computer and a transit vehicle and onboard computer pair of 5 9 GHz Wireless Access in Vehicular Environment WAVE radio modules was manufactured by DENSO Corporation http www denso co jp en The DSRC radio modems and 802 11x wireless adapters were utilized to establish wireless communications between the onboard equipment OBE and the roadside equipment RSE Performance of wireless communication is highly affected by the changing environment in which transmission errors are unavoidable and quite common Wireless signals suffer attenuations as they propagate through space and other obstacles cause absorptions and reflections Communication coverage and latency were tested for both DSRC and 802 11x Wi Fi modules at two different locations East Franklin Avenue at 2274 Avenue and Como Avenue at 29 Avenue in Minneapolis The latency of DSRC radio ranges from 3 to 6 milliseconds at both test sites The latency of the University of Minnesota UMN wireless network ranges from 10 to 30 milliseconds depending on location The DSRC modem has potentially excellent performace with a high data communication rate however the availability of DSRC is limited and we don t know whether there wil
90. es from controller were also collected and sent to central control via cellular communication Iteris Inc www iteris com was recently selected by LACMTA for the design acquisition deployment and ongoing operation and maintenance of bus traffic signal priority systems at 211 signalized intersections maintained by18 local agencies along Manchester Boulevard Garvey Boulevard Cesar Chavez Avenue and Atlantic Boulevard King County MTA in Washington is also planning to design wireless TSP system similar to the implementation in LA County Pace the suburban bus division of the Regional Transportation Authority provides bus services throughout Chicago s six county suburban region Pace recently awarded several research projects to deploy bus rapid transit Cermak Golf Road and south suburban and transit signal priority Cicero Avenue and Rand Road through the SAFETEA LU bill http www pacebus com sub vision2020 federal projects asp Pace is working with a consulting company to identify a wireless based system to provide signal priority to buses and report status and performance back to the transit operation center Signal priority requests for transit or emergency vehicles can potentially be sent to the signal controller through the vehicle to infrastructure communication architecture as described in VII architecture Farradyne 2005 Signal priority for transit vehicles has been studied and proposed as an efficient way to improve transit tra
91. esota By Name Title Date
92. est the data communication between the embedded target computers According to the product specification from LinkSys http www linksys com the access point built into the WRT310N router uses the Wireless N draft 802 11n wireless networking technology The IEEE 802 11n builds on previous 802 11 standards by adding multiple input multiple output MIMO and 40 MHz operation to the physical PHY layer MIMO uses multiple transmitter and receiver antennas to improve the system performance The 40 MHz operation uses wider bands compared to 20 MHz bands in previous 802 11 operations to support higher data rates Wider bandwidth channels are cost effective and easily accomplished with moderate increases in digital signal processing By overlaying the signals of multiple radios WRT310N router s MIMO technology multiplies the effective data rate Unlike ordinary wireless networking technologies that are confused by signal reflections MIMO actually uses these reflections to increase the range and reduce dead spots in the wireless coverage area The robust signal travels farther maintaining wireless connections much farther than standard Wireless G The Wireless N USB adapters were used to evaluate the performance of the wireless router in the outdoor environment The RSE and OBE were each connected to the wireless N adapters and established communications to each other through the WRT310N access point as illustrated in Figure 2 11 Figure 2 10
93. established automatically when the vehicle traveling within the communication range of the wireless network as shown in Figure 5 11b An automation program is need to continuously look for authenticated access point and establish communication as the OBE travels toward the upcoming intersection The wireless network needs to have the capability to establish communication in a timely manner in order for the TSP algorithm to process the priority request efficiently and effectively b Figure 5 11 Establish Wi Fi Connections 35 5 4 Minneapolis Wireless Network In 2006 the City of Minneapolis signed a 10 year contract with USI Wireless of Minnetonka http www usiwireless com to provide city wide wireless broadband technology According to the City of Minneapolis the Minneapolis wireless network will cover all 59 square miles of Minneapolis providing residents businesses and visitors with wireless broadband access anywhere in the city The network will allow the city to deliver services more efficiently and effectively We would like to investigate the possibility of using the USI wireless services for providing transit signal priority through the Minneapolis Wi Fi network We subscribed couple lines of services and purchased two wireless modems for testing The configuration and design of current Minneapolis Wi Fi network does not allow direct TCP UDP communications through their Wi Fi network between the OBE and RSE As illustrated in Figur
94. eters upstream away from the intersection The vehicle gradually moved within the wireless communication range at 25 32 when the adaptive signal priority algorithm began monitoring the location and speed of the test vehicle Priority request was sent at 29 Distance meter around 25 36 to the roadside equipment to request for green extension as the vehicle approaching the intersection The test vehicle arrived at the intersection around 25 46 as illustrated in Figure 5 3 GPS Data T Bus Stop Figure 5 2 Recorded GPS Data Point Along Como Ave SE Eastbound e GPS Data 250 200 150 DSRC Wireless Coverage 597 Vehicle arrives at intersection TT TSP request terminated 25 06 2 25 14 9 25 23 5 25 322 25 40 8 25 49 4 25 58 1 26 06 7 26 15 4 26 24 0 Time mm ss s Figure 5 3 Vehicle Distance to Intersection and DSRC Wireless Coverage Eastbound Test 1 Vehicle speed versus time was also analyzed as plotted in Figure 5 4 The posted speed limit at the test site is 35 MPH We drive the test vehicle at a relative lower speed to represent the lower average bus traveling speed at the test site The test vehicle was traveling with the wireless communication established from 25 32 to 25 56 24 seconds The vehicle was travelling at an average speed of 25 MPH from the time when priority request was sent 25 36 to the time when vehicle passed through the intersection 25 46 There were 4 vehile
95. formation regarding the UDP protocol can be found at Internet Engineering Task Force IETF http www ietf org rfc rfc768 txt Signal Priority Algorithm GPS Process Wireless Communications Wireless Communications Traffic Controller Interface Bus Computer Interface Onboard Equipment UMN TSP Processor Figure 2 14 Software Design of the Signal Priority System 2 4 Signal Control Interface Signal priority request is sent from the RSE to the signal controller through the digital I O board The traffic signal controller needs to be programmed and configured to accept the external input for priority requests Priority phase assignments and bus route information are also needed to help RSE determine where is bus coming from and which phase to provide green extension or red truncation 2 4 1 Signal Priority The Eagle EPAC traffic controller as shown in Figure 2 15 includes provisions for internal preemptors with the capability of handling six unique preempt sequences The preemption program accepts commands from 6 preempt inputs and provides the timing and signal display programmed to occur in response to each Preemption controls are internally applied Internally applied preempt controls will have priority Each preempt input provides two modes of priority control based on the form of the input signal The standard input form is a continuous ground true logic input The 12 alternate input form for low priority is a
96. hen Fu Liao Sr Systems Engineer Minnesota Traffic Observatory MTO ITS Institute CTS Department of Civil Engineering University of Minnesota 500 Pillsbury Drive SE Minneapolis MN 55455 Y include lt stdio h gt include lt string h gt include lt unistd h gt include fcntl h include lt errno h gt include lt termios h gt int open_port int portnum int fd char portfile 20 O if portnum 1 sprintf portfile dev ttySO else if portnum 2 sprintf portfile dev ttyS1 else if portnum 3 sprintf portfile dev ttyS2 else if portnum 4 sprintf portfile dev ttyS3 else printf open port unrecognized port number return 1 if fd open portfile O_RDWR 0 NOCTTY O_NDELAY 1 perror open port unable to open dev ttySO return fd void init port int fd unsigned int baud struct termios options note the termios structure does not support a baud rate of 14400 tcgetattr fd amp options switch baud case 9600 cfsetispeed amp options B9600 cfsetospeed amp options B9600 break case 19200 cfsetispeed amp options B19200 cfsetospeed amp options B19200 break case 38400 cfsetispeed amp options B38400 cfsetospeed amp options B38400 break default cfsetispeed amp options B9600 cfsetospeed amp options B9600 break options c_cflag CLOCAL CREAD options c_cflag amp PARENB options c
97. hh time hour short gps mm time minute double gps ss time second ss ss double latitude double longitude double altitude char lat dir hemisphere N S char long dir EorW double cartesian x state plane in meters east double cartesian y state plane in meters north double height antenna height in meters double hdop 4 is good gt 5 bad double diff_age age of differential GPS data record double speed gps speed in m s double heading heading angle in radians measured from north 0 to east double dt time sec between gps strings int position fix 0 invalid 1 valid SPS 2 valid DGPS 3 valid PPS int num satellites 9 5 bus obu c This is the bus onboard unit OBU to acquire GPS AVL data and send bus data through radio to roadside unit RSU residing in traffic control cabinet for priority request Created on May 20 2007 3 06 PM Copyright Regents of the University of Minnesota All rights reserved ll pr Chen Fu Liao Sr Systems Engineer Minnesota Traffic Observatory MTO ITS Institute CTS Department of Civil Engineering University of Minnesota 500 Pillsbury Drive SE Minneapolis MN 55455 include lt asm io h gt include lt stdio h gt include lt stdlib h gt include lt string h gt include lt errno h gt include lt pthread h gt include
98. hway scenario Marca 2006 performed testing and benchmarked possible throughput of 802 11b wireless communication technology for vehicle to roadside infrastructure communications B hm et al 2008 evaluated different wireless communication technologies including broadcast cell based and dedicated short range technologies and their effectiveness of transmitting road safety relevant information from infrastructure to vehicle I2V as part of the Co operative Systems for Intelligent Road Safety COOPERS program co funded by the European Commission Ahmed et al 2008 developed a blue tooth and wireless mesh networks platform for traffic network monitoring The platform uses traveling cars as data collecting sensors or probes and uses wireless municipal mesh networks to transmit collected traffic data Los Angeles County Metropolitan Transportation Authority LACMTA has implemented wireless technology in a transit signal priority system along several corridors using the IEEE 802 11b protocol Kittleson amp Associates 2006 The wireless system on each bus sends an IP addressable message to an access point that covers three to four intersections A wireless client installed in the signal cabinet communicates with a modified traffic controller firmware to request for signal priority TSP request was sent wirelessly from bus onboard unit to an access point connected to traffic controller through a serial RS 232 interface Bus messages and TSP respons
99. i As Integer Try st idx 0 en idx receivedSentence IndexOf st idx NMEA type receivedSentence Substring st idx idx st idx If NMEA type IndexOf GPRMC 0 Then Fori 2To9 st_idx en_idx 1 en idx receivedSentence IndexOf st_idx If en_idx gt 0 And st_idx lt gt en idx Then Select Casei Case 1 sentence ID NMEA type receivedSentence Substring st idx en_idx st idx Case 2 UTC time UTC str receivedSentence Substring st idx en_idx st_idx G 4 IbITime Text UTC_str Substring 0 2 UTC str Substring 2 2 UTC str Substring 4 Case 3 status PFix str receivedSentence Substring st idx idx st idx Select Case PFix str Case V txtPFix ForeColor Color Red txtPFix Text Invalid Case A txtPFix ForeColor Color Blue txtPFix Text Valid End Select Case 4 latitude Lat str receivedSentence Substring st idx idx st idx tmpStr Lat str Substring 0 2 gpsLat Convert2Double tmpStr tmpStr Lat str Substring 2 gpsLat Convert2Double tmpStr 60 txtLat Text Lat str Substring 0 2 Lat str Substring 2 Case 5 N S indicator NS str receivedSentence Substring st idx en idx st idx IbINS Text NS str If NS str IndexOf S gt 0 Then gpsLat 1 gpsLat End If Case 6 Longitude Long str receivedSentence Substring st idx en idx st idx tmpStr Long str Substring 0 3 gpsLong Convert2Double tmpStr tmpStr Long str
100. idance CCA and its implementation requirements in the context of the vehicle to vehicle wireless network Alexander et al 2006 designed and deployed a transportable rural intersection surveillance system encompassing RADAR Radio Detection and Ranging LIDAR Light Detection and Ranging camera systems and wireless communications between infrastructure and vehicles to investigate the gap acceptance behavior of drivers at rural intersections Wireless communications systems have made rapid progress in the past decade and are commercially available McNally et al 2003 developed an in vehicle GPS based system to provide real time vehicle guidance information through wireless communication technologies Fitzmaurice 2005 reviewed the recent technology advances and regulatory changes that have encouraged the mobile wireless applications in rail and urban transit environments Torrent Moreno et al 2004 investigated a study on the probability of reception of a broadcast message by another car and how to provide priority access for important warnings in 802 11 based vehicular ad hoc networks V ANET One of the key usages of VANET is to support vehicle safety applications through the broadcast operations for informing the immediate neighboring vehicles Stibor et al 2007 evaluated the number of communication partners in communication range and maximum communication duration for a vehicular ad hoc network using the IEEE 802 11p transceivers in a hig
101. innesota Minneapolis MN CTS 06 07 Liu H Skabardonis A Zhang W B 2003 A Dynamic Model For Adaptive Bus Signal Priority Transportation Research Board 8274 Annual Meeting Compendium of Papers CD ROM Washington D C Liu H Skabardonis A Zhang W B Li M 2004 Optimal Detector Location for Bus Signal Priority Transportation Research Record No 1867 Washington D C Marca J E 2006 Mobile throughput of 802 11b from a moving vehicle to a roadside access point Transportation Research Board 85 Annual Meeting Compendium of Papers CD ROM Washington D C McLeod F Hounsell N 2003 Bus Priority at Traffic Signals Evaluating Strategy Options Journal of Public Transportation Volume 6 No 3 pp 1 14 http www nctr usf edu jpt pdf JPT 206 3 pdf accessed October 1 2007 McNally M G Marca J E Rindt C R Koos A M 2003 TRACER In vehicle GPS based Wireless Technology for Traffic Surveillance and Management California PATH Research Report UCB ITS PRR 2003 23 http www path berkeley edu PATH Publications P DF PRR 2003 PRR 2003 23 pdf accessed October 1 2007 Metro Transit 2006 Bottineau Corridor Transit Signal Priority Conceptual Design Minneapolis MN 41 Mirchandani P B Head K L 2001 real time traffic signal control system Architecture algorithms and analysis Transportation Research Part C Emerging Technologies Vol 9 No 6 Elsevier pp
102. ion 201 201 202005 07 5 accessed November 1 2007 Federal Highway Administration FHWA 2004 Traffic Analysis Toolbox Volume III Guidelines for Applying Traffic Microsimulation Modeling Software FHWA HRT 04 040 McLean VA Fitzmaurice M 2005 Use of Wireless Local Area Networks in Rail and Urban Transit Environments Transportation Research Record No 1916 pp 42 46 Furth P G Mueller T H 2000 Conditional Bus Priority at Signalized Intersections Better Service with Less Traffic Disruption Transportation Research Record No 1731 pp 23 30 Furth P G SanClemente J L 2006 Near Side Far Side Uphill Downhill Impact of Bus Stop Location on Bus Delay Transportation Research Record No 1971 pp 66 73 Ghanim M Dion F Abu Lebdeh G 2007 Projected Transit Arrival Time Prediction Tool for Transit Signal Priority with Nearside Bus Stops Transportation Research Board 86 Annual Meeting Compendium of Papers CD ROM Washington D C 40 Hourdakis J Michalopoulos P J Kottommannil 2003 Practical procedure for calibrating microscopic traffic simulation models Transportation Research Record No 1852 pp 130 139 ITS America 2002 An Overview of Transit Signal Priority prepared by Advanced Traffic Management Systems Committee and Advanced Public Transportation Systems Committee of the ITS America Washington D C ITS America 2004 An Overview of Transit Signal Priority revised and
103. ionalities of the Garmin 18 5 Hz GPS receiver The Garmin 18 receiver has the following National Marine Electronics Association NMEA 0183 output sentences including GPALM GPGGA GPGSA GPGSV GRMC GPVTG GPGLL PGRME PGRMF PGRMT PGRMV and PGRMB Garmin proprietary sentences Two sentences GPGGA and GPVTG are used in this project to get the GPS position and ground speed Please refer to Garmin user maul for more detail http www8 garmin com manuals 425_TechnicalSpecification pdf G 2 1 Global Positioning System Fix Data GGA Table G 1 GGA Sentence GPGGA lt 1 gt lt 2 gt lt 3 gt lt 4 gt lt 5 gt lt 6 gt lt 7 gt lt 8 gt lt 9 gt M lt 10 gt M lt 11 gt lt 12 gt hh lt CR gt lt LF gt UTC time of position fix hhmmss format for GPS 18 PC or LVC hhmmss s format for GPS 18 5Hz Latitude ddmm mmmm format for GPS 18 PC LVC ddmm mmmmm for GPS 18 5Hz leading zeros will be transmitted 3 gt Latitude hemisphere N or S A gt lt lt 4 Longitude dddmm mmmm format for GPS 18 PC LVC dddmm mmmmm for GPS 18 5Hz leading zeros will be transmitted lt 5 gt Longitude hemisphere E or W GPS quality indication 0 fix not available 1 Non differential GPS fix available 2 Differential GPS WAAS fix available 6 Estimated Number of satellites in use 00 to 12 leading zeros will be transmitted Horizontal dilution of precision 0 5 to 99 9 Antenna height above below mean sea level 9999 9 to 9
104. ions network along the national roadways that enables communications between vehicles and roadside infrastructure to improve transportation and quality of life The report from Federal Highway Administration FHWA documents the VII architecture and its design requirements Farradyne 2005 Significant amount of research projects focusing on various intelligent transportation systems ITS applications under the VII framework have been investigated since the introduction of the VII initiative Data collected through the VII network could potentially enable hundreds of possibilities including safety mobility and commercial uses from intersection collision avoidance and dynamic route guidance to road level weather advisories and electronic toll collection For example Wischhof et al 2003 and Zhang 2003 investigated the dissemination of vehicle based traffic and travel information through the VII network Wu et al 2005 evaluated the efficiency of message propagation between vehicles through simulation Xu et al 2002 study the effect of vehicle vehicle vehicle roadside communication on the performance of adaptive cruise control ACC systems through simulations Collision avoidance technologies that use the VII infrastructure are also being developed as part of the Cooperative Intersections Collision Avoidance Systems CICAS http www its dot gov cicas index htm initiative Biswas et al 2006 presented the concept of Cooperative Collision Avo
105. ity of Minneapolis is willing to participate as a validation site using a limited number of intersections provided that it is assured that any damages caused to Minneapolis property shall be the responsibility of the University of Minnesota THEREFORE The University of Minnesota hereby provides the following indemnification to the City of Minneapolis In consideration for the City of Minneapolis participation as a validation site the University of Minnesota hereby accepts responsibility for any and all loss injury or damage to the property of the City of Minneapolis that results from the City of Minneapolis participation as a validation site including without limitation any damage to or negative effect on the Eagle traffic control system firmware used in the validation intersections and the University of Minnesota shall pay and indemnify the City of Minneapolis from any and all costs or expenses associated with such damage including costs of replacement or repair material and labor costs and shipping costs including priority shipping Excluded from this indemnity are damages or costs caused by the willful or wanton conduct of employees of the City of Minneapolis however this exclusion applies only to the extent that the costs or damages are attributable to such willful or wanton conduct This letter of indemnity has been approved by an authorized representative of the Regents of the University of Minnesota Regents of the University of Minn
106. king with a consulting company to identify wireless based systems to provide bus signal priority and to report priority status and system performance back to its transit operation center The objective of this study 1s to develop a wireless based Transit Signal Priority TSP system that will integrate the already installed Global Positioning System Automated Vehicle Location GPS AVL system on the buses in Twin Cities An adaptive signal priority strategy developed from phase I study was incorporated to consider the bus schedule adherence its number of passengers location and speed Buses can communicate with intersection signal controllers using wireless technology to request for signal priority Similar setup can also be utilized for other transit related ITS applications The goals of the phase 2 study are to evaluate the performance of DSRC Dedicated Short Range Communication and Wi Fi network develop wireless communication prototype using commercial off the shelf COTS products implement adaptive TSP algorithm and validate the signal priority strategy based on the AVL GPS and wireless technology The City of Minneapolis recently deployed wireless technology to provide residents businesses and visitors with wireless broadband access anywhere in the city Communication with the roadside equipment e g traffic controller for signal priority was tested using the available 802 11x Wireless Local Area Network WLAN or the DSRC modems in vehicular
107. l be national rollout The Wi Fi network has the advantage of using existing infrastructure in Minneapolis however data latency and bandwidth need to be considered The wireless system evaluation helps us better understand the performance of each system and potential constraints while requesting for signal priority in real time application Data communication programs using User Datagram Protocol UDP were developed on a host machine and then later downloaded to both roadside and onboard embedded computers Signal priority request output from roadside equipment was connected to a pre emption input channel on the signal controller inside the controller cabinet Program in the traffic controller was also configured and activated to accept external pre emption inputs The traffic signal controller was programmed by the City of Minneapolis traffic engineer to specify corresponding delay dwell maximum call and extension time Developed prototype systems were deployed and tested at an intersection at Como and 29 Avenue near the University of Minnesota campus to validate the bus signal priority algorithm using different wireless communication protocols The mobile design of the wireless transit signal priority system allows us to test the prototype at different intersections and on different vehicles easily The OBE was placed on a test minivan with GPS receiver and radio antenna mounted on top of the vehicle to represent a transit vehicle The onboard em
108. less network 50 45 40 35 30 gt uu En m AA a SG 15 Be E M e 70 T 6 10 Wireless Communication Latency ms 40 38 8 40 39 6 40 40 5 40 414 40 422 40 43 1 40 44 0 40 44 8 40 45 7 40 46 6 Time mm ss s Figure 4 6 Latency of Wireless Communication Using UMN Wi Fi Network 4 2 Program Signal Controller and Signal Priority Interface Output of the signal priority request from the roadside computer was connected to the pre emption input channel on the signal controller through wirings in the controller cabinet Traffic signal controller was configured and activated to accept external pre emption inputs The traffic signal controller was 23 programmed by the City of Minneapolis traffic engineer to specify corresponding delay dwell maximum call and extension time 4 2 Program Low Priority Pre Emption Input Traffic signal at the intersection of Como and 29 Avenue is controlled by an Eagle MI0 NEMA traffic controller housing in a P type cabinet The NEMA controller allows up to six pre empt inputs from external calls Each pre emption input can operate in high or low priority mode Preemption input 5 in low priority mode was configurred to provide green extension or red truncation to the main street Como Ave in signal phase 2 and 6 for our field testing The low priority input and its settings can be programmed through the LCD interface miscellaneous and low priority menu of the Eagle con
109. lis Wi Fi network for Transit Signal Priority TSP 17 Document Analysis Descriptors 18 Availability Statement Transit Signal Priority TSP Automated Vehicle Location No restrictions Document available from AVL Wireless Communication Dedicated Short Range National Technical Information Services Communication DSRC Springfield Virginia 22161 19 Security Class this report 20 Security Class this page 21 No of Pages 22 Price Unclassified Unclassified 111 A Bus Signal Priority System Using Automatic Vehicle Location Global Position Systems and Wireless Communication Systems Final Report Prepared by Chen Fu Liao Gary A Davis Department of Civil Engineering University of Minnesota Priya Iyer Department of Electrical and Computer Engineering University of Minnesota December 2008 Published by Intelligent Transportation Systems Institute Center for Transportation Studies 200 Transportation and Safety Building 511 Washington Avenue S E Minneapolis Minnesota 55455 The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the information presented herein This document is disseminated under the sponsorship of the Department of Transportation University Transportation Centers Program in the interest of information exchange The U S Government assumes no liability for the contents or use thereof This report does not necessarily reflect the official
110. lt ETX gt B9 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt STX gt lt NUL gt 96 lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt NUL gt lt NUL gt 40 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt A3 F7 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ETX gt lt DLE gt lt ETX gt B8 C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ETX gt lt NUL gt 78 lt NUL gt lt NUL gt lt NUL gt 64 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C1 68 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt D
111. lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 40 7F lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 29 lt DLE gt lt ETX gt A7 A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 29 lt NUL gt lt NUL gt lt NUL gt lt NUL gt 78 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt EOT gt lt NUL gt lt NU L gt lt NUL gt lt NUL gt lt CAN gt lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 38 lt EOT gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt EOT gt lt DLE gt lt ETX gt 4A 35 lt DLE gt 30 lt EOT gt F 2 Hex Dump for Phase Value Seven lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt 2F lt DLE gt lt ETX gt 5C 31 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE
112. lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 9CHE7 lt DLE gt 30 lt gt lt gt 41 30 30 lt gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 25 lt DLE gt lt ETX gt A2 A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 70 3A lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 26 lt DLE gt lt ETX gt A2 52 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 26 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt N
113. map and menu list under debian_bus hud root boot grub directory edit vim fstab under debian_bus hut root etc change defaults ro to defaults errors remount ro with corresponding boot drive dev hda1 PUma board or dev hdc1 for Cobra 5 modify debian_bus hud root etc rc local for program execution after bootup 6 format CF disk mount CF mount dev sda1 media usbdisk format CF use command gparted if auto mounted unmount first GNOME File menu Partition gt umount delete old fat16 partition Partition gt delete check boot in Partition gt manage flags create new partition to EXT3 as Primary partition if error unmount and reformat again use df h to view disk files 7 copy directories cp r hud root media usbdisk sync sync flash with CF 8 remove the media usbdisk boot grub devices map rm media usbdisk boot grub devices map 9 install grub loader sudo grub install root diectory media usbdisk dev sda1 Note grub install wants to install on the computer running it and the devices map does not match the running computer so it complains If you look at the devices map file right after grub install it will match your computer compare boot grub devices map to media usbdisk boot grub devices map Which is wrong so you have to recopy the file from hud root boot grub to the usbdisk 10 cp debian_bus hud root boot grub devices map media usbdisk boot grub C 5 APPENDIX D BUS
114. mm ss s Figure 4 4 Latency of DSRC Wireless Communication at Como and 29th Avenue 22 4 1 2 802 11x Wi Fi Communication Latency Additional testing was also conducted using the Wi Fi adapter through a LinkSys WRT310N router at Como test site The average wireless data communication latency using the Linksys Wireless N adapter is about 23 milliseconds as shown in Figure 4 5 Test vehicle initially established wireless communication with the RSE at 55 35 As the vehicle travelled away from the RSE the OBE lost connection between 56 05 and 56 38 Wireless communication was re established as the test vehicle turned around and traveled within the wireless coverage distance The coverage distance of the Wi Fi system is about 100 meters 50 mu ner Aul eate Faget fne thun N 4 gt No Data Communication 1 m o o 7 7 4 91 55 29 3 55 46 6 56 03 8 56 211 56 384 56 55 7 57 13 0 Time mm ss s Wireless Communication Latency ms Figure 4 5 Latency of 802 11x Wireless Communication at Como and 29th Avenue The wireless prototype system was also tested using the University of Minnesota UMN Wi Fi network The average wireless data communication latency using the Linksys Wireless N adapter WUSB300 is about 15 milliseconds as shown in Figure 4 6 Wireless communication was established as long as the test vehicle stays within the area covered by the wire
115. mmunication Using the Minneapolis Wi Fi network for TSP application can certainly reduce cost by taking advantage of the existing infrastructure However availability of data bandwidth and quality of service concern of network reliability and data security need to be addressed when choosing the Wi Fi technology The DSRC radio is potentially good with excellent performance short range with fast data communication rate but the availability of DSRC is currently limited We certainly don t know whether there will be national rollout The UMN TSP system uses wireless technology to establish data communication between transit vehicles and roadside systems It is not limited to any particular wireless technology 39 REFERENCES 3M Opticom Priority Control System http solutions 3m com wps portal 3M en US Traffic Safety TSS Offerings Systems Opticom accessed October 1 2007 Ahmed H EL Darieby M Abdulhai B Morgan Y 2008 Bluetooth And Wi Fi Based Mesh Network Platform for Traffic Monitoring Transportation Research Board 87 Annual Meeting Compendium of Papers CD ROM Washington D C Alexander L Cheng P Gorjestani A Menon A Newstrom B Shankwitz C Donath M 2006 The Minnesota Mobile Intersection Surveillance System Proceedings of 9th International IEEE Conference on Intelligent Transportation Systems Toronto Canada pp 139 144 Biswas S Tatchikou R Dion F 2006 Vehicle to V
116. n A through location E The vehicle lost communication nearby location B and during the CDE curve The UDP protocol allows the vehicle to re establish the communication with roadside computer as soon as it enters the wireless communication coverage range Wireless signal coverage of the DSRC radio and vehicle GPS data were plotted in Figure 4 1 where X and Y represent the coordinate of the Stake Plane Coordinate System SPSC of Minnesota South FIPSZONE 2203 The wireless communication distance of the DSRC radio is about 650 meters or 325 m radius at 22 Ave and East Franklin Avenue Y meter GPS Data mEBSTOPS AWB STOPS No Signs 318400 4 Start End Location B 5 x X a M 1 a ES A 318350 2 x wu SignalCoverage 650 m 0 4 miles 318300 859200 859400 859600 859800 860000 860200 860400 X meter Figure 4 1 DSRC Wireless Coverage at 22nd and Franklin Avenue The average wireless data communication latency using the Denso DSRC radio ranges between 4 and 6 milliseconds as shown in Figure 4 2 The onboard computer lost it UDP data packets periodically around 39 44 The wireless link was totally lost between 40 05 and 40 10 21 16 5 12 sse se sot tn tmo t 0 00 5 0 Hh Inm dutem inre mene e
117. n Data from MarcNX A 2 Figure B 1 Average Volume B 2 Figure C 1 EPM 5 Block Diagram VersaLogic EPM 5 Reference C 1 Figure C 2 EPM 5 Start Configuration VersaLogic EPM 5 Reference C 2 Figure Connect Relay Output to Controller Cabinet eese eene C 3 Figure C 4 R104 Digital I O Relay Board Layout Tri M Engineering R104 88 User Guide C 4 Figure D 1 Map of Route casi ete Er te n eee RR deat RE D 2 Figure E 1 Denso DSRC Prototype ee ee ai an E 1 Figure E 2 LinkSys Wireless N USB Network Adapter esee enne E 1 Figure GT Garmin GPS 18 Unit etat e e TR e re pte e etnies G 1 Figure G 2GPS Receiver Test Interface ee anerkennen G 3 EXECUTIVE SUMMARY Current signal priority strategies implemented in various US cities mostly utilize sensors to detect buses at a fixed or preset distance away from an intersection Traditional presence detection systems ideally designed for emergency vehicles usually send a signal priority request after a preprogrammed time offset as soon as transit vehicles were detected without the consideration of bus readiness Significant amount of research projects focusing on various intelligent transportation systems ITS applications under the Vehicle Infrastructure Integ
118. nd schedule while providing transit priority RHODES BUSBAND 2 WIRELESS TRANSIT SIGNAL PRIORITY W TSP SYSTEMS A set of PC 104 stand alone Single Board Computer SBC as shown in Figure 2 1 was selected for the embedded system development The Puma series EPM 5 SBC manufactured by VersaLogic http versalogic com and additional I O modules were integrated to perform data communication between traffic signal controller and a transit vehicle A pair of 5 9GHz DSRC Dedicated Short Range Communications prototypes WAVE Wireless Access in Vehicular Environment radio modules manufactured by DENSO Corporation http www denso co jp en and 802 11x wireless modems were used for wireless communications between the embedded computers 11111 Figure 2 1 Puma 104 Plus Single Board Computer 2 1 Embedded Computers The Puma SBC features the AMD GX 500 processor which offers 500 MHz equivalent performance while drawing only one watt of power This highly integrated processor provides extremely fast on board transfers 6 GB per second high speed memory access The Puma can operate as a stand alone SBC or can be combined with specialized PC 104 or PC 104 Plus I O boards for additional functionality Pass through connectors for the PC 104 and PC 104 Plus interfaces provide support for many off the shelf I O boards Block diagram and start configuration of the Puma EPM 5 SBC board is included in Appendix C 1 As shown in Figure 2
119. ng across different municipalities that were unwilling to provide signal priority for transit Results from this previous evaluation study were not promising With the installation of GPS system on its fleet Metro Transit now constantly monitoring bus locations in relation to their schedules in order to provide more reliable transit services and enhance transit operation and management Bus location travel time delay and other traffic information can also be collected and integrated to assist traffic operation management and to inform the traveling public Metro Transit would like to use the already installed GPS AVL system as the basis of a transit based intelligent transportation system ITS Bus information e g speed location number of passengers bus ID can be transmitted wirelessly to a traffic controller or to a regional Traffic Management Center TMC in making decisions to grant signal priority request Several wireless communication systems were installed on Metro Transit buses as standard system configuration An 800 MHz Motorola digital voice radio is used for communication between bus driver and Transit Control Center TCC Another 800 MHz analog data radio is used to poll bus location and passenger count data every minute A Wireless Local Area Network WLAN 802 11x is also installed on the bus to automatically upload or download data files between the bus computer and the central server at TCC when the bus is within the pro
120. nt time sec And estimated time for the bus leaving stop j is i 1 T T 4 The desired signal priority request should then be sent at seconds prior to the bus departure time at stop j That is at time 2 where D eo Pa Eq 5 1 18 the controller processing time f 18 the communication latency time and fon 15 an additional time constant const The signal priority service should be ended at f T where Tis the time for the bus to cross intersection i If both beginning t and ending 1 of the estimated priority service fall within the green split no action needs to be taken at the controller If f jT falls in the green split and f falls in the red split extended green time is needed to ensure that bus could pass the intersection However if the estimated beginning of priority service time 6 falls within the red light period red signal truncation or early green light treatment is needed to provide bus signal priority 3 1 2 Far side Bus Stop For a bus approaching an intersection prior to its arrival at next bus stop for example the bus traveling in westbound as shown in Figure 3 1 signal priority should be provided based on bus traveling speed and traffic conditions The estimated time 7 to arrive at intersection i can be calculated as dus Ta Where d is the distance from westbound bus to intersection i
121. nt to evaluate the data communication latency A simulation program was developed to read the recorded GPS data from a text file and test signal priority request output through wireless communications in the Minnesota Traffic Observatory at University of Minnesota Figure 4 11 illustrates the diagram of the signal priority request by including both roadside and onboard hardware in the simulation This setup provides the flexibility of performing system functional test without interrupting traffic in the field during the system verification process As the vehicle approaches an intersection in the simulation the signal priority request is sent through the digital I O interface in the roadside equipment in this hardware in the loop simulation setup Detail information regarding the R104 88 digital I O board is included in Appendix C 2 Similar simulation testing using the roadside unit to investigate and evaluate the response from the signal control was also performed in the traffic signal shop in the City of Minneapolis Public Works department This 1s to perform the system reliability test and ensure that traffic controller will recover from signal priority requests 25 Onboard Equipment UMN TSP Processor Signal Priority Algorithm GPS Data File Vehicle Location Wireless B Wireless Communications Communications Bus Computer TSP Request Traffic Controller Interface Output Figure 4 11 Block Diagram of Signal Priority Request Simulati
122. null V return 1 start stop daemon start quiet pidfile PIDFILE exec DAEMON DAEMON_ARGS return 2 Add code here if necessary that waits for the process to be ready to handle requests from services started subsequently which depend on this one As a last resort sleep for some time Function that stops the daemon service do stop Return Oifdaemon has been stopped 1ifdaemon was already stopped 2ifdaemon could not be stopped other if a failure occurred kill cat PIDFILE start stop daemon stop quiet retry TERM 30 KILL 5 pidfile PIDFILE name NAME RETVAL RETVAL 2 amp amp return 2 3t Wait for children to finish too if this is a daemon that forks and if the daemon is only ever run from this initscript If the above conditions are not satisfied then add some other code that waits for the process to drop all resources that could be needed by services started subsequently A last resort is to sleep for some time start stop daemon stop quiet oknodo retry 0 30 KILL 5 exec DAEMON 6 2 88 return 2 Many daemons don t delete their pidfiles when they exit rm f PIDFILE return RETVAL gps h file include lt math h gt define MN_STATE_SOUTH 2203 define COORDINATE_SYS MN_STATE_SOUTH define DEG 2 RAD M PI 180 0 typedef struct double gpstime UTC short gps month short gps day short gps year short gps
123. numbytes 0 printf Server Received s n buf this is the child process if fork child does not need the listener H 11 close sockfd printf Reached Inside if sendto sockfd buf numbytes 0 struct sockaddr amp their_addr sin_size 1 perror Server sendto error lol close sockfd exit 0 else printf Server send is OK n parent does not need this close sockfd while return 0 H 12 APPENDIX 1 INDEMNITY LETTER LETTER OF INDEMNITY FOR BUS SIGNAL PRIORITY BASED ON GPS AND WIRELESS COMMUNICATIONS PHASE IT WHEREAS the University of Minnesota Center for Transportation Studies is undertaking a research program for bus signal priority based on GPS and wireless communications which has advanced to Task 4 system validation WHEREAS the GPS Bus Priority System may represent a significant advancement over bus priority systems currently in use in various cities WHEREAS all Metro Transit busses currently are equipped with GPS and a validated system could rapidly be implemented with the current Metro Transit fleet WHEREAS traffic simulation has demonstrated that the GPS system would not cause traffic problems for non bus vehicles and would significantly improve transit performance reducing delays improving adherence to schedules reducing fuel costs and greenhouse gas emissions making transit a more attractive option and WHEREAS the C
124. on 4 3 Field Testing Como Avenue and 29 Avenue SE Como and 29 Avenue as shown in Figure 4 12 was selected by the City of Minneapolis and Metro Transit as our test site The selected intersection located relatively far away from nearby signal intersections operates as a standalone intersection with no coordination with nearby signalized intersections The isolated characteristic of the intersection offers great opportunity to perform functional test for the wireless based signal priority system Aerial photo of the test site is shown in Figure 4 13 Bus route 3 operates along Como Avenue and carries significant amount of riders each day There are 220 bus trips along Como Avenue on a regular weekday Detail trip count information and route map of bus route 3 is included in Appendix D The test vehicle will traverse between the 27 and 31 Avenue along Como Avenue during the testing Vehicle location speed priority request status time were recorded on a USB memory stick on the onboard computer Detail information regarding the phasing and timing settings at Como and 29 Avenue is included in Appendix A Traffic count and turning movement collected by the City of Minneapolis in 2006 is also included in Appendix B Figure 4 12 Transit Signal Priority Test Site 26 Figure 4 13 Aerial of Como and 29th Avenue SE in Minneapolis from Google com The developed prototype systems as described previously were deployed at Como and 29
125. on and speed Bus location and its distance corresponding to the next bus stop and signalized intersection were calculated to identify a nearside versus a far side bus stop scenario The control diagram for the priority strategy is shown in Figure 3 2 Bus dwell time at each stop was computed based on the passenger arrival using the Poisson distribution Bus travel times to the intersection and the bus stop were calculated to determine when to submit priority request prior to its arrival at the signalized intersection Signal priority settings in the controller were programmed to provide green extension or red truncation The EPAC controller is running on a background coordination cycle to ensure that the intersection returns back to its timing and stays coordinated with the neighboring intersections Readintersection andbusstop data Nearside bus stop Farside bus stop Estimate bus dwell arrival time at bus stop andtravel time to next intersection Figure 3 2 Block Diagram of Transit Signal Priority Strategy 20 4 EXPERIMENT SETUP AND TESTING Performance of wireless communication is highly affected by the changing environment in which transmission errors are unavoidable and quite common Wireless signals suffer attenuations as they propagate through space and other obstacles cause absorptions and reflections Communication coverage and latency were tested for both DSRC and 802 11x Wi Fi modules to better understand the performance
126. ority request was sent at around 59 30 to the roadside equipment to request for early green or red truncation as the vehicle approaching the intersection Priority request was granted and the signal turned green around 59 40 The test vehicle arrived at the intersection at around 59 45as shown in Figure 5 5 Speed MPH 59 110 59 19 7 59 28 3 59 37 0 59 45 6 59 542 00 02 9 00 11 5 00 20 2 Time mm ss s Main Street Traffic Light Figure 5 6 Vehicle Speed Profile and TSP Request Eastbound Test 2 Vehicle speed versus time for the early green scenario was analyzed as plotted in Figure 5 6 The test vehicle was traveling within the wireless communication range from 59 24 to 59 56 duration of 32 seconds The vehicle was travelling toward the signalized intersection when the signal light is red Signal priority was requested when the test vehicle began to slow down due to the queue in front of the test vehicle Traffic controller acknowledged the priority request and provided an early green around 59 41 After receiving the green light on the main approach the speed of the test vehicle increased as the queue in front began to discharge Test vehicle left the intersection around 59 45 at speed around 16 MPH The average wireless data communication latency is about 4 1 ms for the eastbound test 2 using the DSRC radio 5 1 3 Westbound Signal Priority Request for Early Green Red Truncation Signal priority request for red trun
127. ped prototype systems were deployed and tested at the intersection of Como and 29 Avenue nearby the University of Minnesota campus to validate the bus signal priority algorithm with green extension and red truncation early green strategy The mobile design of the wireless TSP system allows us to easily test the prototype system at different intersection and on different vehicle The OBE was placed inside a minivan with GPS receiver and radio antenna mounted on top of the vehicle to represent a transit vehicle The onboard embedded system interfaces with the GPS and wireless communication systems to transmit vehicle location and other information for example vehicle ID route ID passenger counts door opening status and so on to the roadside equipment The RSE continuously monitors the vehicle location when it travels within the communication range of the wireless network The RSE will generate signal priority request to traffic signal controller as governed by the TSP strategy implemented in the RSE The field test results demonstrate that the test vehicle 1s able to successfully submit signal priority request through the wireless network as it is traveling toward the intersection instrumented with roadside equipment The vehicle is initially traveling from a location outside the DSRC WAVE radio coverage range As soon as the vehicle moves within the wireless communication range the adaptive signal priority algorithm begins to monitor the location and
128. ration VIT framework have been investigated since the introduction of the VII initiative Data collected through the VII network could potentially enable hundreds of possibilities including safety mobility and commercial uses from intersection collision avoidance and dynamic route guidance to road level weather advisories and electronic toll collection Wireless communications systems have made rapid progress in the past decade and are commercially available Los Angeles County Metropolitan Transportation Authority MTA has implemented wireless technology in a transit signal priority system along a corridor using the IEEE 802 11b protocol The wireless system on each bus sends an IP addressable message to an access point that covers three to four intersections wireless client installed in the signal cabinet communicates with a modified traffic controller to request signal priority King County MTA in Washington is also planning to design wireless TSP system similar to the implementation in LA County Pace a suburban bus division of the Regional Transportation Authority provides bus services throughout Chicago s six county suburban region Pace recently was awarded with several research projects to deploy bus rapid transit Cermak Golf Road and south suburban and transit signal priority Cicero Avenue and Rand Road through the Safe Accountable Flexible Efficient Transportation Equity Act A Legacy for Users SAFETEA LU bill Pace 1s also wor
129. s at nearside bus stops Kim and Rilett 2005 proposed a weighted least squares regression model in simulation to estimate bus dwell time in order to overcome nearside bus stop challenges Ghanim et al 2007 developed an artificial neural network modeling tool to predict intersection bus arrival time on approaches with nearside bus stops Rakha et al 2006 performed field and simulation evaluation along US Route 1 corridor They recommended further consideration on existence of queues in transit signal priority strategy and suggested no near side bus stop implementation Furth and SanClemente 2006 investigated the impact of bus stop location on bus delay They found far side bus stops cause small reduction in delay or no effect Nearside bus stops more often increase bus delay A bus priority algorithm could also be integrated into an adaptive intersection signal control model Research based on the bus priority facilities available within the Split Cycle Offset Optimization Technique SCOOT traffic signal control system was conducted by Bretherton et al 1996 Traffic signal priorities can be controlled by a central SCOOT computer or by a local traffic signal controller A local controller can achieve faster TSP response to buses than a centralized control Different strategy options for providing bus priority at signals are compared by McLeod amp Hounsell 2003 using the simulation model called Selective Priority to Late buses Implemented at Tr
130. s at the command prompt of the target machine This would allow you to know the IP address Start the communication between both the devices E 5 APPENDIX F SERIAL COMMUNICATION WITH THE EPAC M40 TRAFFIC CONTROLLER In order to communicate with the traffic controller and read its data we monitored the serial communication carried out by the MarcNX software with the device The MarcNX software was provided by the SEIMENS Ltd MarcNX software obtains phase data by carrying out multiple combinations of commands namely Write Set RTS Clear RTS Read and Set timeouts within an iterative loop The communication for obtaining phase data is a 2 way mode where in the software performs the write operation by writing a certain data characters and waits for the device to write the same piece of information This whole operation happens in a timeout mode However the serial monitor software which 1 am using can capture only the first 100 bytes of data in every operation Due to loss of the protocol information describing the frame format memory location command checksums etc and our study could not reveal the proper commands to communicate with the device We captured new upload session for Phase Value of 6s and 7s The Advanced Serial Port Monitor tool from AGG Software is used to check the flow of data through computer s serial COM port The serial port analyzer is used to control and monitor serial devices right from the PC It supports
131. s in front of the test vehicle during the experiment But detail traffic condition in front of the test vehicle was not captured due to the insufficient data from the loop detectors 30 Speed MPH 25 06 2 25 14 9 25 23 5 25 322 25 40 8 25 494 25 58 1 26 06 7 26 15 4 26 240 Time mm ss s Figure 5 4 Vehicle Speed Profile and TSP Request Eastbound Test 1 e GPS Data 250 200 ne vo 150 w 100 8 a 50 0 59 11 0 59 197 59 28 3 59 37 0 59 45 6 59 54 2 00 02 9 00 11 5 00 20 2 Time mm ss s DD Main Street Traffic Light Figure 5 5 Vehicle Distance to Intersection and DSRC Wireless Coverage Eastbound Test 2 5 1 2 Eastbound Signal Priority Request for Early Green Red Truncation Another scenario was also tested to evaluate the controller s response to priority request for early green In Figure 5 5 the vehicle was intentionally started when the signal on Como Avenue turned red The DSRC wireless communication was established from 59 24 to 59 56 Signal light on Como Avenue was red as the test vehicle approaching the intersection Signal priority was requested through the wireless communication at 59 30 Figure 5 5 shows the distance from the test vehicle to the intersection versus time The test vehicle was initially idling at about 180 meters upstream away from the intersection The adaptive signal priority algorithm began monitoring the location nand speed of the test vehicle at 59 24 31 Pri
132. s information from the existing AVL system and bus mobile infrastructure in order to reduce intsllation and maintenance cost and implementation time We would like to build upon our previous research effort on wireless TSP and work together with the City of Minneapolis and Metro Transit to improve the transit reliability and run time adherence in the Twin Cities 37 7 SUMMARY AND DISCUSSION The objective of the phase II study is to develop a wireless based transit signal priority system that will incorporate the Global Positioning System Automated Vehicle Location GPS AVL system on the buses while determing when to submit priority request to signal controller An adaptive signal priority strategy developed from phase I study was implemented to consider the bus schedule adherence its number of passengers location and speed Buses can communicate with intersection signal controllers using wireless technology to request for signal priority or other ITS applications Communication with the roadside unit e g traffic controller for signal priority was tested using the available 802 11x WLAN and the DSRC Dedicated Short Range Communication prototype system for wireless access in vehicular environment A set of PC 104 stand alone Single Board Computer SBC was used for the embedded system development Additional I O modules were integrated to the embedded system to perform data communication between the traffic signal controller and a transit vehi
133. s ported to the host machine recompiled and downloaded to the target computers for testing Transmission Control Protocol TCP is optimized for accurate delivery rather than timely delivery TCP sometimes incurs relatively long delays in the order of seconds while waiting for out of order messages or retransmissions of lost messages and it 15 not particularly suitable for real time applications The User Datagram Protocol UDP does not guarantee reliability or ordering in the way that TCP does UDP faster and more efficient is suitable for time sensitive applications that do not need guaranteed delivery UDP is used to establish the data communication between the OBE and RSE UDP uses a connectionless communication setup A process using UDP does not need to establish a connection before sending data and when two processes stop communicating there are no additional control messages Communication consists only of the data segments themselves A network node can communicate with another network node using UDP without first negotiating any kind of handshaking or creating a connection Because of this UDP is very efficient for protocols that send small amounts of data at irregular intervals UDP provides a message oriented interface Each message is sent as a single UDP segment which means that data boundaries are preserved However this also means that the maximum size of a UDP segment depends on the maximum size of an IP datagram More detail in
134. se is different from the priority phase phase arrangement such as phase suppression or red truncation is needed to provide green time to the buses minimum green time has to be served prior to terminating the phase There has been some concern about returning the intersection timing to its original coordination after providing signal priority to buses Some priority strategies require many cycles before the signal timing is resynchronized to its regional coordination Siemens 2002 Recently an advanced controller provides the signal priority recovery with a cycle by including optional transit phases in the timing plan Siemens The bus signal priority strategy will resynchronize to its neighbor intersections in the next cycle by reducing the amount of green time extended in the next cycle priority phase Signal priority requests in the following cycle will be ignored in order to facilitate coordination recovery For example if the request from bus A or B in cycle i was granted at an intersection priority requests from bus C and D will not be considered because cycle i will be used for coordination recovery 19 3 5 Signal Priority Implementation The priority strategy was implemented using the C programming language and compiled on a Linux host machine Executable binary code was then downloaded to each OBE and RSE When a bus travels within the wireless communication range the signal priority program will continuously monitor the bus locati
135. speed of the test vehicle and submits request for priority through the roadside interface to the traffic signal controller Traffic signal controller is capable of providing green extension or red truncation or early green to the qualified vehicle as it is approaching the intersection The signal priority request 1s dropped when the test vehicle passes the intersection or when the call duration reaches the maximum call setting 38 An experiment to test the signal priority systems using the Minneapolis Wi Fi network was also attempted But the configuration of current Minneapolis Wi Fi network does not allow direct TCP UDP communications through their network servers between the OBE and RSE Both OBE and RSE receive dynamic IP addresses assigned under the private network connected through to the wireless modems or adapters The OBE or RSE can freely communicate to the world through the Minneapolis Wi Fi network However the OBE cannot communicate with the RSE directly through the Wi Fi network due to security settings from the USI wireless servers We were advised by the USI wireless technical support to use third party software to communicate between our onboard and roadside equipment through Minneapolis Wi Fi network The data communication latency might be increased significantly when introducing additional layer of data communication However the variation of the network latency plays a more importance role for realtime application using wireless co
136. stem EventArgs Handles recTimer Tick recLatLongStr SPCS XY toStr recDataSize 1 xtError Text rec recDataSize ToString End Sub Private Sub btnClear Click ByVal sender As System Object ByVal e As System EventArgs Handles btnClear Click rcvdBuffer End Sub End Class APPENDIX SAMPLE SOURCE CODE H 1 Bus Onboard Unit Sample Source Code etc rc local script file bin sh e rc local su root c etc init d runrsu start amp exit 0 etc init d runrsu script file bin sh PATH should only include usr if it runs after the mountnfs sh script PATH sbin usr sbin bin usr bin DESC Daemon for running the RSU unit NAME prog_rsu_udp DAEMON usr sbin S NAME DAEMON_ARGS options args PIDFILE var run NAME pid SCRIPTNAME etc init d SNAME Exit if the package is not installed x DAEMON exit O Read configuration variable file if it is present r etc default SNAME amp amp etc default 8NAME Load the VERBOSE setting and other rcS variables lib init vars sh Define LSB log_ functions Depend on Isb base gt 3 0 6 to ensure that this file is present lib Isb init functions Function that starts the daemon service do start Return Oifdaemon has been started 1if daemon was already running 2ifdaemon could not be started start stop daemon start quiet pidfile PIDFILE exec DAEMON test gt dev
137. t 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 20 lt DLE gt lt ETX gt A1 F2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt BS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt DLE gt lt NUL gt lt NUL gt lt N UL gt lt NUL gt lt NUL gt lt CAN gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 38 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 40 lt NUL gt lt DLE gt lt ETX gt CC A5 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 21 lt DLE gt lt ETX gt A0 62 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 21 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt
138. t 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt ETX gt lt DLE gt lt ETX gt B8 C2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt ETX gt lt NUL gt 78 lt NUL gt lt NUL gt lt NUL gt 64 lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt ETX gt 84 lt ETX gt 84 lt NUL gt 50 lt NUL gt 8C lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 4F lt DLE gt lt DLE gt 20 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt C1 68 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt EOT gt lt DLE gt lt ETX gt BA F2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt EOT gt lt NUL gt 3C lt NUL gt lt NUL gt lt NUL gt 3C lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt SOH gt 2C lt SOH gt 2C lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 23 lt NUL gt lt GS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 30 lt NUL gt lt NUL gt 40 40 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt
139. t lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt lt RS gt 76 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 24 lt DLE gt lt ETX gt A3 32 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 24 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt E TX gt 9CHE7 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt 25 lt DLE gt lt ETX gt A2 A2 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt 25 lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt N
140. t lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 3E 7A lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt LF gt lt DLE gt lt ETX gt BE 92 lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt LF gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt RS gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DLE gt lt ETX gt 2D 78 lt DLE gt 30 lt EOT gt lt EOT gt 41 30 30 lt ENQ gt lt DLE gt 30 lt DLE gt lt STX gt lt EM gt lt DC4 gt lt ACK gt lt VT gt lt DLE gt lt ETX gt BF lt STX gt lt DLE gt 31 lt EOT gt 61 30 30 lt ENQ gt lt DLE gt lt STX gt lt ACK gt lt VT gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt LF gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt DC4 gt lt NUL gt lt DC4 gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt lt NUL gt 28 lt NUL gt lt D
141. ter detection Engineers usually have to adjust the detector location receiver line of sight and timing offset for each intersection in order to ensure its effectiveness Liu et al 2004 presented a theoretical model to quantitatively address the relation between bus detector location and effectiveness of transit signal priority systems Li et al 2007 proposed an active signal priority optimization model for Light Rail Transit LRT in a simulation study by estimating the train travel and dwell time Most TSP strategies do not consider the transit s speed and its distance from the intersection when determining the appropriate time to request signal priority Metro Transit in Twin Cities Metro area http www metrotransit org previously performed an evaluation to provide signal priority for buses on Lake Street in Minneapolis using 3M Opticom systems A special software modification was made to provide transit priority using green extension and red truncation strategies However the Opticom system ideally designed for emergency vehicle preemption EVP was not able to adjust the trigger timing for buses approaching nearside bus stops and buses often missed the priority green period when they were ready to depart Since several intersections along Lake Street were already operating at their capacity the potential for providing transit priority without delaying vehicle traffic was somewhat constrained There were also issues of buses traveli
142. th Avenue SE in Minneapolis from Google com 27 27 28 Figure 5 1 Bus Receives Signal nnne nenne nnns 29 Figure 5 2 Recorded GPS Data Point Along Como Ave SE 30 Figure 5 3 Vehicle Distance to Intersection and DSRC Wireless Coverage Eastbound Test 1 30 Figure 5 4 Vehicle Speed Profile and TSP Request Eastbound Test 1 30 Figure 5 5 Vehicle Distance to Intersection and DSRC Wireless Coverage Eastbound Test 2 31 Figure 5 6 Vehicle Speed Profile and TSP Request Eastbound Test 2 32 Figure 5 7 Recorded GPS Data Point Along Como Ave SE Westbound sse 33 Figure 5 8 Vehicle Distance to Intersection and DSRC Wireless Coverage Westbound 33 Figure 5 9 Vehicle Speed Profile and TSP Request Westbound sene 34 Figure 5 10 Controller Data Collection Interface from SMART SIGNAL 35 Figure 5 11 Establish Wi Fi 35 Figure 5 12 Wireless Data Communication through a 3rd Party 36 Figure A 1 Como and 29th Avenue Geometry Layout and Phase Assignment eese A 1 Figure A 2 Signal Timing Data from MarcNX 2 Figure Intersectio
143. tion on new fd int sockfd new fd address information struct in my_addr H 10 connector s address information struct sockaddr_in their addr int sin size struct sigaction sa int yes 1 int numbytes char buf MAXDATASIZE if sockfd socket AF_INET 5006 DGRAM 0 1 perror Server socket error lol exit 1 else host byte order my addr sin family AF_INET printf Server socket sockfd is OK n short network byte order my addr sin port htons MYPORT automatically fill with my IP my addr sin addr s addr htonl INADDR_ANY printf Server Using 96s and port d n inet ntoa my addr sin addr MYPORT zero the rest of the struct memset amp my addr sin zero O 8 if bind sockfd struct sockaddr amp my_addr sizeof struct sockaddr 1 perror Server bind error exit 1 else clean all the dead processes sa sa_handler sigchld handler sigemptyset amp sa sa mask sa sa flags SA RESTART printf Server bind is OK n if sigaction SIGCHLD amp sa NULL 1 perror Server sigaction error exit 1 while 1 sin size sizeof their addr if numbytes recvfrom sockfd buf MAXDATASIZE 1 0 struct sockaddr amp their addr amp sin size 1 perror recvfrom exit 1 else printf Server The recv is OK n buf
144. tr As String Dim GPVTG str Heading str Knot str As String Dim rcvdBuffer As String Dim gpsLat gpsLong As Double Dim gpsLatLong As New Point2D Dim sentenceSize As Integer 2 Dim recordSize As Integer Dim SPCS XY As New Point2D Private Sub GpsDisplay Load ByVal sender As System Object ByVal e As System EventArgs Handles MyBase Load SPCS XY New Point2D rcvdBuffer Timer1 Enabled True recLatLongStr End Sub Private Sub Timer1_Tick ByVal sender As System Object ByVal e As System EventArgs Handles Timer1 Tick read serial buffer Dim header i header As Integer Read the NetworkStream into a byte buffer Output the data received from iServer Dim iBytes sent i As Integer Dim receivedSentence tmpStr As String For sent i 1 To sentenceSize iBytes moRS232 Read DATA SIZE rcvdBuffer moRS232 InputStreamString header i rcvdBuffer IndexOf header rcvdBuffer IndexOf header i 1 If header i gt 0 And header gt 0 And header gt header i Then receivedSentence rcvdBuffer Substring header i header header i rcvdBuffer rcvdBuffer Substring header IbIBufLen Text rcvdBuffer Length Else Exit Sub End If dataRcvd moRS232 InputStream If CheckBoxLog Checked Or sent i 1 Then NMEAStr_Box Text receivedSentence Else NMEAStr_Box Text receivedSentence End If NMEAStr Box SelectionStart NMEAStr_Box TextLength parse lat long alt etc Dim st_idx en_idx
145. troller as shown in Figure 4 7 and 4 8 0 NO amp LINK PEF DURATION LOCK OUT UU B 1 2723 45 2 5 0 D d 0 R F PRIOR MENU LOW PRIORITY N LOCK EXTEND 000 DURATION LOCK OUT 000 E ENTER F PRIOR MENU Figure 4 8 Preempt 5 Low Priority Menu The low priority menu includes options to specify the dwell delay and extend settings DELAY is the waiting time that the low priority actuation must be activated prior to normal signal controller operation being interrupted for the low priority routine EXTEND is the additional time that the low priority actuation should be extended from the termination of the actuation DURATION is the time required by the preemption prior to a transition back to normal controller operation DWELL is the time offered to provide green on the priority phase MAXCALL is the time that a low priority call can remain active and be considered valid Figure 4 9 illustrates the corresponding priority settings of the Eagle M40 signal controller Figure 4 10 shows that traffic engineer Scott Tacheny from the City of Minneapolis programmed signal priority settings in the controller prior to the field testing 24 lt gt Max Call Priority Call Priority Green Delay Dwell Extend Figure 4 9 Low Priority Signal Priority Request Tae m Figure 4 10 Program Eagle Traffic Signal Controller 4 2 2 Signal Priority Request Simulation Vehicle location was recorded in previous experime
146. troller using the proprietary commands Signal controller firmware usually needs to be modified by the controller manufacturer in order to accept the external commands It is very difficult to obtain the communication protocol of the traffic controller due to the proprietary nature Traffic Controller Wireless Client Onboard With Modified RT Wireless or Router Firmware Client Figure 2 16 TSP Initiation Thrugh Serial or NTCIP Interface 13 Wiring diagram of a single preemption channel is illustrated in Figure 2 17 Two wires from the normally closed output of the R104 digital I O board were connected to the preemption input and the 24VDC logic common respectively NEMA controllers require a standard 6 25 Hz signal at 50 duty cycle for the low priority input logic circuits and a ground true logic for the high priority or preemption continuous 6 25 Hz pulse signal low priority call for transit vehicle priority calls was generated from the RSE when bus is ready to pass through upcoming intersection Standard Traffic Controller Minneapolis P Cabinet PRE EMPT IN5 579B 24 VDC 41 42 Do not connect to 599 TSP Processor AVL amp Onboard and Wireless Wireless Client Router Client Router R104 Digital 1 0 Relay Board N O Figure 2 17 Wiring Diagram from R104 I O Board to Controller Cabinet 2 4 3 Priority Phase Selection and Configuration A priority phase selection table is configur
147. user ID E 2 Username Password Command logfile created by Lynx 2 8 5rel 1 04 Feb 2007 0 lynx Argl accept_all cookies Arg2 cmd script myCommandScript Arg3 www google com key y key lt space gt key s key t key u key d key x key 0 key 8 key J keyt key s key p key P keyr key o key j key key 1 key J key J key y key Down Arrow key Right Arrow key key q key J key y Save the above script in a file called connect After receiving an IP address from the UofM wireless network execute command at the prompt lynx accept all cookies cmd script myConnectScript www google com This should allow you to connect to the UofM Wireless network E 4 2 Automatic script generated by the lynx Go to home scripts If scripts directory does not exists then create a folder under home After receiving an IP address from the UofM wireless network execute command at the prompt gt The user could also create a new connection script by specifying the following command E 3 gt lynx all cookies log myLogScript www google com Note When invoking the google com link the connection could automatically bring the wireless network access authentication UI Specify UMN X500 Userid and Password when prompted This should allow you to connect to the UofM Wireless network the logging sequence of commands would be sa
148. ved in the filename as specified with the option myLogScript Next time after rebooting use the same script for calling the command 6 lt lynx accept all cookies cmd script myLogScript www google com User can also execute the following script file myExtIP sh to obtain external IP address when using the Minneapolis wireless network bin bash wget www whatismyip com automation n09230945 asp O o dev null echo exit 0 Execute this at the command prompt of the target machine This would allow you to get the external IP address Start the communication between both the devices E 5 Test Minneapolis Wi Fi Network Using Ruckus Modems Steps Connect the ruckus modem to the Ethernet port Ensure that the modem is powered on and has enough strength Note that this modem would work only for USI wireless network Ensure that the interfaces file has the following details This file describes the network interfaces available on your system and how to activate them For more information see interfaces 5 The loopback network interface auto lo iface lo inet loopback The primary network interface auto ethO iface 6110 inet dhcp E 4 After starting the machine one should notice that the machine gets connected to USI wireless network automatically After this create a file called myExtIP sh bin bash wget www whatismyip com automation n09230945 asp O o dev null echo exit 0 Execute thi
149. vel time and schedule adherence to reduce transit operation costs and to improve customer riding quality Signal priority strategies have helped reduce the transit travel time delay as discussed in the literature ITS America 2002 but the transit travel time reduction varies considerably across studies Collura et al 2006 Unlike signal preemption which interrupts the normal intersection signal process to provide high priority for special events emergency vehicle or railroad crossing transit signal priority TSP modifies the normal signal operation in order to accommodate better service for transit vehicles ITS America 2004 Transit signal priority has been implemented in several US cities Seattle Portland Los Angeles and Chicago as well as in Europe Various technologies have been deployed for bus priority including Opticom St Cloud 2000 inductance loop detectors Los Angeles and RF tag Seattle King County 2002 Recently Crout 2005 at Tri County Metropolitan Transportation District of Oregon TriMet proposed two types of analyses corridor and intersection level to evaluate the effectiveness of the TSP effort on transit operations over 300 signals implemented with signal priority Current signal priority strategies implemented in various US cities mostly utilize sensors to detect buses at a fixed or at a preset distance away from the intersection Signal priority is usually granted after a preprogrammed time offset af
150. x 5 idx vehSpeed Convert2Double Knot str 1 150779448 convert from knot to MPH txtSpeed Text Convert ToString Convert ToUInt1 6 vehSpeed Case 7 unit N Knot Case 8 speed Case 9 speed unit K Km h End Select End If Next i End Sub Private Sub btnGraph Click ByVal sender As System Object ByVal e As System EventArgs Handles btnGraph Click If ISNothing frmGraph Then frmGraph New GraphXY Display the new form frmGraph Show Else If Not fr mGraph IsDisposed Then frmGraph WindowState FormWindowState Normal frmGraph BringToFront Else frmGraph New GraphXY frmGraph Show End If End If End Sub Private Sub chkRec_CheckedChanged ByVal sender As System Object ByVal e As System EventArgs Handles chkRec CheckedChanged If chkRec Checked Then recLatLongStr recDataSize 0 recTimer Enabled True Else recTimer Enabled False Dim result As DialogResult result MessageBox Show Save recDataSize ToString recorded data Record Lat Long data MessageBoxButtons YesNo MessageBoxlcon Question MessageBoxDefaultButton Button1 If result DialogResult Yes Then Dim myStream As System IO Stream If SaveFileDialog1 ShowDialog DialogResult OK Then myStream SaveFileDialog1 OpenFile Dim w As New BinaryWriter myStream If Not myStream Is Nothing Then w Write recLatLongStr End If End If End If End If End Sub Private Sub recTimer_Tick ByVal sender As System Object ByVal e As Sy
151. x 1 break end of switch field index break default break end of switch sentencelD return 0 end of parseGPSField pr client UDP c Created on July 20 2007 3 06 PM Copyright Regents of the University of Minnesota All rights reserved pr Minnesota Traffic Observatory MTO ITS Institute CTS Department of Civil Engineering University of Minnesota 500 Pillsbury Drive SE Minneapolis MN 55455 a stream socket client function include lt stdio h gt include lt stdlib h gt include lt unistd h gt include lt errno h gt include lt string h gt include lt netdb h gt include lt sys types h gt include lt netinet in h gt include lt sys socket h gt include lt signal h gt include lt setjmp h gt include lt sys time h gt include clientTCP h define RECV_TIMEOUT 1 timeout in seconds static sigjmp_buf timed out timeout handler void timeout handler int signum signal SIGALRM SIG DFL siglongjmp recv timed out 1 int send2RSU char message char hostname int sockfd numbytes char buf MAXDATASIZE struct hostent he connector s address information struct sockaddr_in their addr cliAddr get the host info if ne gethostbyname hostname NULL perror gethostbyname exit 1 create a socket for connection if sockfd socket AF_INET SOCK_DGRAM 0
152. ximity of the transit garage Researchers at California PATH Partners for Advanced Transit and Highways studied an Adaptive Bus Signal Priority ABSP to apply an active priority strategy for buses by including bus GPS information traffic detector data and a travel time predictor to an adaptive model Liu et al 2003 Wadjas and Furth 2003 developed a methodology by adapting advanced detection and cycle length to provide transit signal priority The adaptive control includes traffic density and queue length estimation in a simulation study Skabardonis and Geroliminis 2008 developed an analytical model for real time estimation of arterial travel time A signal priority algorithm extends the active signal priority strategy initially proposed by Skabardonis 2000 was developed and incorporated into their base model to provide system wide adjustments to the signal timing plans and priority based on the real time traffic information Li et al 2005 proposed a heuristic TSP algorithm to provide signal priority to buses as well as limit negative impact on cross street traffic Traditional TSP strategies implemented in United States are mostly fixed location detection systems and implemented with time of day signal control systems TSP systems using fixed location detection usually do not work well with nearside bus stops due to the uncertainty in bus dwell time Zheng et al 2007 developed a theoretical model to estimate the corresponding delay

A Bus Signal Priority System Using Automatic Vehicle Location

Contents

Download Pdf Manuals

Related Search

Related Contents