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Automatic vehicle location for measurement of corridor level of service


Material Information

Automatic vehicle location for measurement of corridor level of service "The Miami Method"
Running title:
Miami Method
Physical Description:
28 p. : ill. ; 28 cm.
Miami (Fla.) -- Dept. of Planning, Building, and Zoning
University of South Florida -- Center for Urban Transportation Research
University of South Florida, Center for Urban Transportation Research
Place of Publication:
Tampa, Fla.
Publication Date:


Subjects / Keywords:
Global Positioning System   ( lcsh )
Intelligent transportation systems -- Florida   ( lcsh )
Motor vehicles -- Automatic location systems -- Florida   ( lcsh )
bibliography   ( marcgt )


Includes bibliographical references (p. 26.).
Additional Physical Form:
Also available online.
Statement of Responsibility:
by the Center for Urban Transportation Research, College of Engineering, University of South Florida.
General Note:
"September 1994."
General Note:
Prepared for the City of Miami Department of Planning, Building and Zoning.

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University of South Florida Library
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University of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 026092023
oclc - 42000358
usfldc doi - C01-00420
usfldc handle - c1.420
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Automatic vehicle location for measurement of corridor level of service :
"The Miami Method" /
by the Center for Urban Transportation Research, College of Engineering, University of South Florida.
1 7 246
Miami Method
[Tampa, Fla.] :
University of South Florida, Center for Urban Transportation Research,
28 p. :
ill. ;
28 cm.
"September 1994."
Prepared for the City of Miami Department of Planning, Building and Zoning.
Includes bibliographical references (p. 26.).
Also available online.
Global Positioning System.
Intelligent transportation systems
z Florida.
Motor vehicles
x Automatic location systems.
Miami (Fla.).
Dept. of Planning, Building, and Zoning.
University of South Florida.
Center for Urban Transportation Research.
t Center for Urban Transportation Research Publications [USF].
4 856


Automatic Vehicle location for Measurement of Corridor level-of -Service: The Miami Method Prepared for the City of Miami Department of Planning Building and Zoning by the Center for Urban Transportation Research College of Engineering University of South Florida


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AUTOMATIC VEHICLE LOCATION FOR MEASUREMENT OF CoRRIDOR LEVEL oF SERVIcE: "THE MIAMI METHOD" prepared for the City of Miami Department of Planning, Building and Zoning (Project No. 150002, Account Code No. 560703) by the Center for Urban Transportation Research College of Engineering University of South Florida {Project Account No. 21-17-125-LO} September 1994


AVL for Measurem('nf of Couidor LOS ACKNOWLEDGMENTS The Center for Urban Transportation Research (CUTR) would like to recognize and thank several key individuals for their assistance and contribut io n s to this evaluatio n p roject and r e port. Clark Turner served as the p roject originator and manager for the Ciry of Miami Stephen Tine was the primary liaison and coordinator with the project vendor, AirTouch Teletrac Others f rom Air Touc h Teletrac who provided assistance during th i s project were Seth Miller (contract admin istra t ion), Allen l-lum (Vice Preside nt and General Manager-Miami Operations), Miguel Lopez (softwar e training) Ward Benjamin (insta llat ion trouble-shooter), Doron Ben -Yehezkd and John Mango (technology consu l tants) Michael Duckett (RF Field Technician), and Mark Licht (Executive Vice President and M-IS coord in ator). Mario Bizz io an d Joseph Morffi two University o f Miami undergraduate tran s portation engineering students who worked for Clark Turner t hro ughou t this project, paiticipated in validation tests and manned the project workstation at the City of Miami's office Mike Moore, of the Dade Co unry MPO, provided l i nk node map data for the City of Miami. The25 volunteer test drivers recrnited by the City of Miami (in addi ti on to Clark T urner, Mario Bizzio and Jose ph Morffi } included Mark Alvarez. Dennis Boyd ,James Campbe ll P. Court ney Collins Jo hn Cox, Ken Cox, Alex David, Sarah Eat on, Bill Fogarty, Francisco Garcia, Olga Garcia, David LaGrae, Sandra Latey, Hector L ima, Enrique Nunez, Fernando Paiva, Harold Ruck, Kathleen T urner, Maria Wallace, Tom Wammack, Dave Whittington, and Karen Wilson. Finally, the principal in vestigator f or this evaluation and report was Michael Pietrzyk, Senior Research Associate and M-IS Progra m Manage r at CUTR. Data compilat i on, eval uat ion analysis, and customized reporting sof tware were developed by Amy Polk, CUTR Research Associate. Report graphics wer e pr e pared by graduate student research assistants Lisa Argiry,Joseph Hagge and Venkat Vani kuti. R eport design and editing were done by Patricia Henderson, CUTR Communications Manager, and Janet Becker, CUTR Pr ogram Assistant. 2 "The Method"


' AVL for McNJ.Wn:mt.nt of Corridor LOS I CONTENTS Executive Summary ............. ... ... ................ ...... ......... .............................................. .... .... 5 Background .. .... ... .. .... .. ........ .... ... ... ............................ ............................. .. ..... .. .... ....... 6 AVL Technology Description ............... ......... ..... ...... . .......... ......... ... ... ..... ... .... 9 Evaluation Description........................................................ ... ........ .. .... .... ..... ..... .. ....... 13 Evaluation Results......................... ....... ...... ........................................ ............................ 18 Conclusion and Recomm endation for Future Tests ......... ........ .......... .... ... ... .... ........ 25 References ....................................... .............. ...... ........................................................... 26 'The Miami Mcrllod" 1 3


AVL fot Measurement of Corridor LOS


AVL for Me

AVL for MeMuremenf of Conidor LOS BACKGROUND Determination of roadway level-of-service (LOS) plays an important role in Florida's future_ U nder Florida's 1985 Growth Management act, "a dequate" public infra s tructure must be available in an area to support future development for development to occur. There are seven types of public facilities. However, one typetransportation-is ofien the determining factor for whether or not new develop ment can go forward. Adequacy is defined by LOS standards, which are adopted by local governments as part of thei r local comprehensive plans. In commenting on th e 1985 Growth Management Act, the Florida Departme nt of Tran s porta tion (FOOT) referenced, and the Department of Community Affairs (DCA) later adopted, t he roadway level-of-service determination process described in the 1985 High111a,y Capaci{y Manual (HCM). That methodology based its determination on vehicle operating speeds, a paradigm shift from the 1965 HGM, which based its methodology on a volume-to-capacity ratio. However, direct measurement of operat ing speeds by field observation was a labor inten sive and relative costly alternative (at least, until recently). The 1985 HCM, therefore, outlined a series of formulas to estimate roadway operating speeds from static not trip specific, variables. Unfortu nately, due to the highly dynamic nature of vehicle operating conditions, the Hw'vf formulas have been found to yield results with significant error com ponems. It is believed tha t recent technological advances in signal processing and mobile communications can make direct measurement of vehicle operating speeds an inexpensive and accurate alternative to conventional means of speed data collection and monitoring. A u tomatic vehicle locat io n is a means o f cominuoJIJfy monitoring the location of vehicles in a road network_ For the AirTouch T eletrac A VL system, vehicles are equipped with \chide locating units (VLUs), which include a transponder t h e size of a commo n VHS tape t hat u niquely identifies each vehicle and a palm-sized, "pancak e ante nna t hat transmits and receives r ad io-frequency (RF) communica tion signals in the 900 MHz band to a central location at regular intervals. Birth of the "Miami Method" The standard methodology for determining roadway LOS proved to be unworkable for the City of Miami. Th a t methodology penalized Miami as a densely-populated urban area, failed t o recognize the added value o f the area's extensive tran sit network capacity, and would have allowed for no new development in the city. I n 1989, the City developed a new methodology for roadway LOS determination that was innovative in several ways. It used persontrips, not vehicle-trips, as the basic uni t of travel demand and it measured all available transportation capacity a long transportation corridors that could include rail lines and bus transit routes as well as roads. Miami's method measured 6 "The Miitmi Method"


AVl. for Mc.muement of Conidor capacity as a perc e ntage o f the s um of seats in individual vehicles o n roadways and seat s o n a t r ansit v e hicle, either rail or bus. The Mia mi metho dology currently uses a person-trip based vehicle to c apacity as th e determin ant of c orri d or level-of-setvic e but i t propos e s to use average speeds a s the LOS measurem e nt, b ased o n the ou tcome of t hi s eval uation. Th e City Plann i ng Divis i o n i den t ifie d 17 transporta t ion co rrid o r s within the city bou ndaries. They are shown in Figur e 1. Figur e 1 MIAMI' S TRANSPORTATION C O RRIDOR S .,.. ... i N 0 t .-. .. 2 6rni I "Tile Miami Method" 7 I


AVL fo1 Mt:-.-uuremenr of Corr1dor LOS In 1988, Clark Turner, transportation planner for t he City of Miami proposed that A VI. t echnology cou l d be used t o measure vehicl e speeds on specific corridors. In J 994 City o f Miami staff approached the Center for Urba n Tr an sportation Rese-.uch (CUTR) at the Un iversity of South Florida in Tampa to set up an evaluation of the use of A VI. to measure average vehicle travel speeds on Miam i's 17 corridors In accordance with Resolution No. 94-97 from the Cit y Commission meeting of Feb ruary 17, 1994, throug h a grant from the Metropolitan Planning Organization for the Miami Urbanized Area, the C ity Manager was authorize d t o e ngage the services of CUTR to prepare a technical study "toward refinement and com pletion of the City's Transporta ti on Corridors Plan." This p l an represents the transportation element of t h e Miami Comprehens iv e Neighborhood P lan for 1989-2000. AirTouch Teletrac CUTR recruited AirTouch Teletrac to serve as the vendor of the AVL system. AirTouch Tel etrac was recruited because of its local presence, proven customer s atisfaction, and willingness to participate in the evaluation. W i th corporate h eadquarters in Garden Grove, California, Air Touch Teletrac is a joint ven t ur e between A ir Touc h Comm uni cations (formerl y "PacTel Co r poration ") and North A m erica n Teletrac and i s a leading provider o f wireless commercial and consumer vehicl e l ocat ion and related mobile data commun i cations services. Recently, it was announced that AirTouch Communications and U.S. West intend to combine their cellular telephone operat i ons to f orm a $17 bill ion wireless management company over the western half of t he U.S. serving 1 6 of t he na ti on's top 30 markets F or this evaluation, AirTouch T ele trac agreed to provide 25 vehicle location units, one workstation an d o ne copy of it s Fleet Di rect or .. software to th e City of M i ami for a 113-day period a t nominal cost {to cover installa tion and removal ofVLUs). Th e A irT ouch T eletrac A VI. system uses gro un d -based radio-navigat i o n in six U.S. metropolita n areas: greate r Los Angeles, Chicago, De troit Dallas/Ft Wort h, Hous t on and th e Great er Miami area. AirTouch Teletrac sells its services to both commercial fleets that use the system for computer-aided d ispatching and fleet monitoring and private vehicle owners who use the system for stolen vehicle recovery and emergency roadside assistance. I n south Flori da A ir Touch Teletrac curre n tl y mai ntai n s a network of 27 receJvtng antennas t hr oughout Da d e Broward, and Palm Beach counties. Its A VI. system is capa ble of tracking vehicles anywhere in the tri cou nty area. AirTouch Teletrac guarantees the accuracy o f its AVL system to the nearest 150 feet (0.028 miles or 0.000417latitudinaV longitudinal units) in any of i t s six metropo lit a n areas of coverage. AirT ouc h T eletrac s taff state t h at, because of south Florida's relativel y flat terrain, the accuracy o f the south flo r ida system i s w i thin the nearest 50 fee t (0.0094 mi les or 0 .000139 latitudinal/ l ongitu d inal units) 8 'The Mi

Signals the receiving antennas are transmitte

AVL for Measurement of Corridor LOS Signpost When vehicles that regularly travel a fixed route, such as transit buses, many fleet operators have found chat signpost -based positioning systems offer an affordable alternative to more advanced A VL technologies. Antennas are placed at locations throughout the vehicle's known route and record the time when the vehicle passes. A signpost-based A VL system also can be a valuable byproduct of systems int e nded for other purposes. For example, reader antennas that communicate with vehicle tags for Electro nic Toll Collection (ETC, also known a s Automatic Vehicle I dentification or A VI) also can track the location of vehicles from one toll booth to another. The Harris County Toll Road Authority in Houston and the Illinois State Toll Highway Authority in Chicago are currently using such systems. Drawbacks to signpost -based systems include their inability to track vehicles off their norma l route. Ground-Based Radio-Navigation In "terrestrial" or "ground -based" radio-navigation theAVL vendor sets up several receiving antennas in a metropo lic;,n area. Each equipped vehicle broadcasts a radio-frequency (902-928 MHz) signal to all nearb y receiving antennas From the time it takes for the signal to travel to the antenna, the distance of the v ehicle to the antennas can be determined. I f the vehicle's signal was received by three or more antennas the vehicle's posit i on can be uniquely determined (i.e., multi -lat eration). Since the variable cost per vehicle is low, ground-based radio-navigation systems are among th e most in expensive A VL systems for the user. However, since the fixed cost of constructing the necessary infrastruCture requires significant financial investment on the part of the A VL vendor, these systems usually are available only in dense urban areas with large market potential. LORANC LORANC (Long-Range Aid to Navigation ) uses low frequency radio waves to provi de signa l coverage. The federal goven unem set up the communication system to aid the U.S. Geological Survey in mapping. Instead of using multiple receivers to locate a signal transmitter LORAN uses a single r eceiver to locate multiple transmitters. LORAN.C often experiences radio frequency and electromag netic interfer ence Close proxim ity to overhead power lines and RF signal booster stations in urban and industria l areas can cause significant error on the time difference calculations. In addition, LORAN-C positioning systems can experience error due to poor signal reception in urban canyons. Due to t hese drawbacks and uncertainty about the government's future plans for this system, a decrease in the number of commercial AVL systems using LORAN.C has occurred. Global Positioning System (GPS) Global Positioning Systems (GPS) use a network of24 satcUites in a geosynchronous orbi t with Earth. Antennas capable of receiving these satellit e signals can determine their own location. GPS antennas 10 MMmi MNhod"


AVL for of Corndor LOS receive the sa tellite signals free of charge; however, a license must be obtained. The U.S. Depar t ment of Defense launched the satellites in order to track objects of interest on the ground. The system was used to track tanks and even individual soldiers during the Persian Gulf War. Differential GPS {DGPS) One potential problem using GPS for automatic vehicle location is that the Department of Defense intentionally degrades the accuracy of GPS positioning data used for non -defense purposes Several companies have addressed the need for additional accuracy by manufacturing systems that broadcast the corrections to the positioning data to special receivers ("differential GPS receivers"} using a variety of wireless transm i ssion media. Technology Options Compared According to a comparative analysis of positioning technology performed for Metro Mag&in<, while GPS and DGPS are the most accurate of positioning technologies, they are also the most expensive. LORAN-C, radio-navigation, and GPS signals have some difficulty transmitting through large obstructions, such as mountains, tunnels parking garages, and urban canyons formed by large buildings that line many downtown city streets. GPS signals also have trouble transmitting through opaque ob jects such as leaves on trees. The Teletrac System The Teletrac system takes advantage of several technologies (e.g., digital paging, digital mapping, spread spectrum transmission, LORAN-C l ocation computation algorithms, and multi-processor distributed network control center}, which were originally developed to support the needs of other markets. T eletrac is licensed to operate a vehicle interrogation signal frequency and a location signal frequency transmitted by the vehicle location unit. The T eletrac radio-navigation system includes a series of simulcast high power pagin g transmitters and specialized receiver sites constructed at strategic locations throughout the metropo litan coverage area. The receiver sites gather signals from the VLUs as well as from the simulcast transmitters Receiver sites are located at high elevation locations for maximum signal visibility, and, given the particular conditions of the urban environment, Time Differences of Arrival (I'DOA} measurements from a minimum of four receiving sites are required to compute a vehicle's location (thus the multi l ateration location technology). The time delay measurement from the receiver sites is processed to compute the vehicle's latitude and longitude. Figure 2 shows a diagram of AirTouch Teletrac's multi lateration location concept, as supplied by AirTouch Teletrac Corporation. "Tite Mii:lm; Method" 11


AVL for Measurement of Corridor LOS Figure 2 BASIS CONCEPT OF THE CONCEPT OF THE LOCATION ALGORITHM Third Line of Posn. to resolve ambiguity Line of Posn.C-D D B Line of Posn. A-B Loc.atlons are computed using the lines of constant time differences between pairs of receive sites. These Time Difterences of Arrival (TDOA) form hyperbo las which cross at the location ofthe vehicle Additional lines of position from redundant receive sites allow ambiguous or "'ghost .. positions to be elim i nated. In order to obtain a mathematically unique solution, a minimum of4 sites must r ece i ve the transmission from the vehicle. Generally the greater the number of receive sites, the higher the accuracy and rel i abilicy of the location. AfrTouch Proprietary 0 1994. All rights reserved 12 Tiw MMm


AVL for MPastuement Conldor LOS EVALUATION DESCRIPTION The project kickoff meeting occurred on March 23, 1994. Vehicle installation of t he AVL devices occurred on April II, 12, and 21. Software training for Fleet Director"1 was provided by Air Touch T eletrac on April 14 at tl1eir Ft. Lauderdale office, and workstation installation at t he City P lanning office followed thereafter The 113-day, continuous field evaluati on began April 25 and officially ended August 15. The overall project completion date was September 30, 1994. W it hin its corporate boundaty area, the City of Miami previously had been divided into 1 7 travel corridors fr om which level-of-service measures were proposed to be collected and monitored. The test a r e a for tl1e project encompassed t his area, more specifically the travel corridors. To the greatest extent possible, the City of Miami recruited vol unteer drivers, who provided travel coverage along the 17 trave l corridors. Roles and Responsibilities City of Miami The City of Miami provided the financial sponsorship for this evaluation project The City was responsible for recruitment of the 25 drivers and for providing a suita bl e convenient workstat ion area wit hin the City admini s tr a tion buil ding in d owntown Miami Also, two U niversity of Miami und ergraduate transportation engineering stud e nts, working as interns for the City, provide d assistance in travel data gathering and workstation monitoring. CUTR CUTR designed imp lemented, and monitored the tests an d provided a writt e n eval uation summary un der contr act to the City. CUTR recruited and negot iated the cost-sharing agrocment with the private vendor (Air Touc h Teletrac) to provide the A VL system to the City for this evalua tion. CUTR also was r esponsib l e for developing the general evaluation plan and assessing the general accuracy and reliabi l it y o f t he tra\el speed data gathered during t he project. Finally, CUTR also was responsibl e for preparing a proposed scope o f work for the next p hase of this pro ject (discussed later in thi s report) which will identifY and assess t he broad technological and transpor ta tion planning/monitoring app li cation issues regar ding the "M iami Method for LOS measurement and integration into Congestion Management System (CMS) applications. AirTouch Teletrac Under a subcon trac tor agreement with t he University of South Florida, Air T ouch Teletrac provided the followin g f o r purposes of the evaluation: 'The Miami Method" 13


AVL for of Corridor LOS T eletrac Fleet Director'" workstation and software for a period of 60 days, later extended to I 13 days. 25 T eletrac vehicle location units (VLUs) for a period of 60 days, later extended to 113 days. Technical support and workstation training for project personnel on the use of the Teletrac system and Fleet Director" software. I nstallation and removal of the 25 vehicle location units also was performed by AirTouch T eletrac Only costs associated w ith the installati on, removal, and temporary usage of vehicle location units specificall y for t he I 13-

AVL for Mf!asurement of Co1ndor LOS "pancake" antenna. The control unit is installed underneath the steering column and wired to the ignition; the antenna is installed between the roof of the car and the roof interior. Although the interior of the car appears to be entirely d i sassembled during insta ll ation, once installation is complete it is impossible to detect that the VLU has been installed. Figure 3 shows the installa tion of one of the 25 VLUs. Figure 4 shows the transponder and pancake antenna com ponents before instal lation. Figure 3 VLU INSTAL LATI O N : "The Miami Method" 1 S


A VI for of Corridor LOS Figure 4 VEHICLE LOCATOR UNIT During Apri l 14 software training sion, it was discovered that the transponders did not report w hen the vehicle ignition mrne d on and off, a capability most AirTouch Teletrac t r an sponders possess. This function was need ed s o t hat, during the data analysis phase, it cou l d be determined when a trip began and ended, so as to determine the average speed over the entire trip. The firmware o f the units installed on April I I and 12 had to be re-configured which too k place on April21, a long w it h insta ll a tion o f the remaining 11 transponders. The situation was quickly resolved, and the d at a collection began o n April25, 1994, as scheduled. A ir T ouch s taff delivered the Fleet Directo rTM workstation a Compaq 486 computer running the Fleet DirectorTM soft ware wit h i nterna l high -speed (14,400 baud} modem-to the City of M iami on A pril 15. Th e City provided a dedicat e d phone line for continuous communication between the workstati on and A i r Touch T e l etrac's operations cente r in Ft Lauderdale. Polling Frequency CUTR configured th e software to poll t he position of each of the 2 5 vehicles every 30 seconds w h en t he vehicle ignition was on, and every 5 minute s when the vehicle ignit io n was off Although t h e Telmac systoin is capable of po lling with a frequency o f up to e very 8 seconds, this interval is not desirable when using the system to determine average vehicl e speeds from location data As an example, a vehicle traveling an average of 1 2 miles per hour travels only 140 feet in 8 seconds. However, the posit i onal accuracy of the Teletrac system was g u aranteed only to within a radius of 150 feet. Consequently, for traveling at this speed, it would be impossible to det ermine w hether the change in location was due to t h e fuct tha t the vehicle was in mot i on or due 16 "The Miami Method"'


AVL for MciuuramPnt of Corridor LOS to positional inaccuracy of the Teletrac syst em. AirTouch Teletrac staff recommended a polling frequency of every 30 secon ds, which cou ld detect vehicles in motion traveling at average speeds as low as four miles per hour. Fleet Director Software Each time a vehicl e's posit i on was recorded, l ocation appeare d in the following form: F or example: Vehicle number, average speed, dire ct ion, time (hour, minute, second), date and loc ation (lat itude. l ongitude ) 1342 35E 07:36:33am 0 4 / 25/9 4 25. 7 4728 80.21642 1342 3SE 07:36:33am 04/25/94 POINCIANA B lVD. btw 24TH AVE and 25TH AVE City of M iami Transportatio n P l anning staff r equested vehi cle l ocatio n da t a for the followin g peri ods: Weekday mornings, 5:00am to 1 O:OOam Weekday afternoons, 3 : 00p m to 8:00pm Saturdays, 1 O:OOam to 2 : 00pm CUTR research staff configured the Fleet Di rector'l'M software to write vehicle location data to a file (in ASCII format) for these periods. In the end.of-day summary repo rts, a vehicle's locat ion cou l d reported in either o f two ways: coor dinates in la ti tude and longitude or street name and nearest cross streets. S ince both forms of information would be helpful during the d ata analysis p hase, the software was configured to make two reports for every reporting peri od. The six files t hat com p ri sed t h e end of-

AVL for Measurement of Co rridor LOS At the end of each day, the Fleet DirectorTM software would append that day's vehicle location data to the existing tile, creating a new tile if none existed. All six reports amassed over 4 5 megabytes of vehicle location data every week. Since there were only 40 megabytes of free memory on the Fleet Director'"' workstation's hard disk drive, City of Miami staff were instructed to make a copy of all .RPT'' tiles at the end of each week, erase those tiles, and send a backup copy to CUTR in T ampa for ;maysts. Between April 25 and August 15, the experiment amassed almost 150 megabytes of vehicle location data, recording over 4,400 trips Excerpts from these reports appear in Figures 5 and 6 Hosted Site Visit(s) One scheduled site v i sit to Miami was hosted by the project team during the course of the evaluation period. The purpose of this hosted site visit was to display the working environment of the evaluation and share interim findings with interested parties from Florida Department ofTransportation. This one-day event occurred on July 19, 1994. The City, CUTR, and Air Touch Teletrac were available for questioning from visitors; several eval uation fleet vehicles (with cellular phones) also were available for direct participation in validation tests. Other informal site visits during the evaluation period were coordinated as j ointly agreed to by the project team. Following the completion of the evaluation and final report, it will be important to share findings locally, statewide, and nat ionally. To the greatest extent possible, dissemin ation will be strategically coord i nated among the City, CUTR, and AirTouch Teletrac and targeted to such groups as the City of Miami, Metro-Dade MPO, FOOT, Florida MPOs, Florida Department of Community Affairs, Florida League of Cities, Florida Association of Counties. Florida Section of the Institute of Transportatin Engineer s (lTE), national ITE, Transportation Research Board, and ITS AMERICA (formerly IVHS AMERICA}. EVALUATION RESULTS Data Analysis CUT R research staff wrote two softwar e programs to analyze the vehicle location data and report average speed. "SPEED.EXE" computes the speed of a vehicle over its entire trip from the moment the vehicle i gnition is turned on to the moment the vehicle i gnit i on is turned off. "SEGMENT.EXE" computes a vehicle's speed from the moment it enters to the moment it exits a pre defined road segment along a trip (defined by the geographic coordinates of its beginning and ending points.) Both programs were written in the C computer language, using a TurboC compiler. Excerpts from sample ompm files from each program appear in Figure 7. 18 The Mtar> Method"


' AVL for Measun'm(}nt of Conidor L&5 I Figure 5 SAMPLE EXCERP T FROM E ND-OF-DAY REPORT : LATITUDE & LONGITUDE l&b!ill Time Rate Locl!ti.onaiJent 0676 0 06: 39: 45arn 07/07/94 25.69226 -so. 35769 0676 0 06:44:48arn 07/07/94 25.69241 -80.35774 0676 0 06:49:46arn 07/07/94 25.69232 -80.35757 0676 0 06:54:47arn 07/07/94 25.69241 -80.35744 0676 0 06:59:46am 07/07/94 25.69234 -80.35763 0676 0 07:04:49arn 07/07/94 25.69237 -80.35761 0676 0 07:10:25am 07/07/94 25.69213 -80.35774 0676 07:09:53am 07/07/94 RCV [41) VEHICLE ON 0676 07:09:53am 0 7/07/94 Driver Status Changed. 0676 0 07:09:53arn 07/07/94 25.69217 -80.35789 0676 ** 07:10:46arn 07/07/94 25.69091 -80. 3 5746 0676 0 07:11:23am 07/07/94 25.68696 -80.35800 0676 0 07:11:51am 07/07/94 25.68687 -80.35784 0676 48SE 07:12:19am 07/07/94 25.68681 -80.35351 0676 35E 07:12:48am 07/07/94 25.68704 -80.34898 0676 34N 07:13:15am 07/07/94 25.69061 -80.34787 0676 49NE 07:13:48arn 07/07/94 25.69458 -80. 34199 0676 61E 07:14:16am 07/07/94 25.69515 -80.33433 0676 62E 07:14:49arn 07/07/94 25.69473 -80.32521 0676 63E 07: 15 : 17am 07/07/94 25.69479 -so. 31729 0676 49E 07:15:49arn 07/07/94 25.69490 -80.31021 0676 9NE 07:16:17am 07/07/94 25.69556 -80.30929 0676 29E 07:16:45arn 07/07/94 25.69588 -80.30564 0676 0 07:17:20am 07/07/94 25.69567 -80.30111 0676 44E 07:17:47arn 07/07/94 25.69586 -80.30025 0676 28NE 07:18:19arn 07/07/94 25.69801 -80.29695 0676 0 07:18:48am 07/07/94 25.70011 -80.29349 0676 51NE 07:19:15arn 07/07/94 25.70163 -80.29216 0676 0 07:19:48arn 07/07/94 25.70251 -80.29045 0676 42NE 07:20:16arn 07/07/94 25.70509 -80.28841 0676 35NE 07:20:48am 07/07/94 25.70805 -80.28455 0676 38NE 07:21:17am 07/07/94 25.71105 -80.28090 0676 39NE 07:21:48am 07/07/94 25.71429 -80.27673 0676 35NE 07:22:16am 07/07/94 25.71683 -80.27334 Both programs use two methods to compute average travel speed. Method 1 averages the speed rec o r di ngs made by the Fleet Directorw. software over the trip Method 2 calculates the cumulative d istance t raveled by the vehicle (from recording to recording), then divides by the tot a l time elapsed. The F leet Di r ector1"' software calculates average vehicle speed in l a rgely the same ways-the distance "The Miami Mothod" 1 9


Label 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 0676 Speed 0 0 0 0 0 0 0 0 0 0 48SE 35E 34N 49NE 61E 62 63E 49E 9NE 29E 0 44E 28NE 0 SlNE 0 42NE 35NE 38NE 39NE 35NE Figure 6 EXCERPT FROM END-OF-DAY REPORT: STREET ADDRESS 06:39:45am 06:44: 46am 06:49: 46am 06:54: 47am 06:59: 46am 07:04: 49atn 07:10:25am 07:09:5Jatn 07:09: 53 am 07:09:53am 01:10: 46a:m 07:ll:23am 0 7:11:51am 07:12: 19am 07:12:46am 0 7:13:15am 07:13:48am 07:14:16am 07:14:49am 07:15: 1 7am 07:15: 49am 07:16:17am 07:16:45am 07:1 7:20am 07:17: 47am 07:18:19am 07:18: 48am 07: 19: lSam 07:19:48am 07:20:16am 07:20:4Bam 07:21:17a m 07:21:48am 07:22:16am pate Location/Event 07/07/94 SW 102ND AV btw SW 62ND TERR & SW 81ST ST KENDALL 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 81ST ST. KENDALL 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 81ST ST. KENDALL 07/07/94 SW 102ND AV btw SW 82NO TERR & SW 81ST ST. KENDALL 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 61ST ST. KENDALL 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 81ST ST. KENDALL 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 81ST ST. KENDALL 07j07j94 RCV (41) VEHICLE ON 07j07/94 Driver Status Changed. 07/07/94 SW 102ND AV btw SW 82ND TERR & SW 61ST ST. KENDALL 07f07f94 SW 102ND AV btw SW 84TH ST & SW 82NO TERR KENDALL 07/07/94 SW 102ND AV btw SW 88TH ST & SW 87TH ST. KENDALL 07/07/94 SW 88TH ST btw SW 102ND AV & SW lOlST AV. KENDALL 07/07/94 SW 88TH ST btw SW 98TH CT & SW 99TH CT. KENDALL 07/07/94 SW 88TH ST btw SW 96TH AV & SW 97TH AV. KENDALL 07/07/94 SW 96TH AV at SW 95TH AV. KENDALL 33173 07/07/94 SNAPPER CREEK EXWY btw SW 87TH AV & S DADE EXWY. 07/07/94 SNAPPER CREEK EXWY btw SW 87TH AV & S DADE EXWY. 07/07/94 SNAPPER CREEK EXWY btw SW 79TH AV & SW 82ND AV. 07/07/94 SNAPPER CREE K EXWY btw SW 76TH AV & HWY 826. GLENVAR 07/07/94 SNAPPER CREEK EXWY btw SW 72ND AV & SW 76TH AV. 07/07/9 4 SW 80TH ST btw SW 72ND AV & SW 71ST AV. GLENVAR 07/07/94 SW 80TH ST btw SW 7 1ST AV & SW 69TH AV. GLENVAR 07/07/94 SW 67TH AV btw SW 81ST ST & SW 80TH ST. GLENVAR 07/07/94 SW 8 0TH ST btw SW 67TH AV & SW 66TH AV. GLENVAR 0 7/07/94 US 1 btw SW 80TH ST & SW 6 2ND AV. SOUTH MIAMI 33143 07/07/9 4 SW 62ND AV btw SW 76TH ST & US 1 SOUTH MIAMI 33143 07/07/94 US 1 btw SW 61ST AV & SW 62ND AV. SOUTH MIAMI 33143 07/07/94 SW 59TH CT btw S W 74TH ST & SW 73RD ST. SOUTH MIAMI 07/07/94 US 1 at SW 72ND ST. SOUTH MIAMI 33143 07/07/94 US 1 btw YUHURI ST & SW 57TH AV. CORAL GABLES 33146 07/07/94 US 1 btw S W 57TH AV & MARIPOSA CT. CORAL GABLES 07/07/94 US 1 btw MARIPOSA CT & CABALLERO BLVD. CORAL GABLES 07/07/94 HOMESTEAD AV btw AUGUSTO ST & MARIUS ST. CORAL


AVL for Me<1surement of Couidor LOS traveled since the last location recorded divided by the time elapsed. I n Method I, if the distance traveled is less than a certain threshold (0.015 miles, 79.2 feet o r 0.000224 latit u dinal /longitudinal units), the Fleet Director"' software assumes that the difference in vehicle location readings is due to inaccuracy o f the positioning technology and sets the speed a t zero. In addition, the Fleet Director"'' softv1are uses the following comersion factors for miles per geographic coordinate units, averaging conversion ''alues for all the cities in w hich Air T o uch Teletrac has AVL systems operating: latitude: 1 geogra p h i c unit -67.495 m i les Longit ude: 1 geographic unit = 67.495 miles Figure 7. SAMPLE ANALYSIS RESULTS start: 0676 0 07:09:53am 07/07/94 25.6921 7 -80.35789 description: 102ND AV btw SW 82ND TERR f. SW 81ST ST. KENDALL 33173 end: 0676 47 07:33:48am 07/07/94 25.77577 -80.19951 description: 3RD AV btw NlY 3RO ST & mr 2ND ST. l1IAMI 33128 total distance 1 (in miles): total distance 2 (in miles): total time difference (in hours) : avera9e speed 1 (in miles per hour): average speed 2 (in miles p,er hour): 12.28833 13.32528 0.39861 30.82788 33.42928 start: 1342 description: o 07:1o:44am 07/07/94 25.72659 -80.33197 end: 1 342 45TH ST btw SN 85TH AV & SW 84TH AV. OLYMPIA HEIGHTS 33155 o 07:33:48am 07/07/94 25.77573 -80.19904 description: 2ND ST btw 3RD AV & NW 2ND AV. MIAIH 33128 total distance 1 (in miles): total distance 2 (in miles): total time difference (in hours): average speed 1 (in miles per hour): average speed 2 (in miles per hour): 10.12500 10.50811 0.38444 26.33670 27.33323 start: 1389 0 07:35:55am 07/07/94 25.77191 -80.35276 description: NW 4TH TERR. 33172 end: 1389 35 08:06: 18am 07/07/94 25.77388 -80.19957 description: W FLAGLER ST btw I 95 & I 95. MIAMI 33130 total distance 1 (in miles): total distance 2 (in miles): total time difference (in hours) : average speed 1 (in miles per hour): average speed 2 (in miles per hour): 12.40333 12.73180 0.50639 24.49369 25.14233 Note: Method f averages FleetOirectofiMs values for vehicle speed over entire trip. Method 2 averages values for distance traveled over time elapsed between location readings. 'The Mi

AVL for Measurement of Comdor LOS Method 2 uses the following conversion factor s for miles p e r geographic unit, using specitlc telemetry measu rements for south Florida: L a ti tude: 1 geog rap hic unit 62.729 mi les Longi tude : 1 geo graphic uni t 69.387 m iles Method 2 was also shown to have a higher degree of accuracy. Data Validation In order to determine the accuracy of the "SPEED.EXE" program's calculat i ons for average t ravel speeds, CUTR researchers set up a validation process to compare observed values to calculated values for the average speed over a vehicle trip. City of M i am i T r a n sportation P lannin g staff, who were driving equipped vehicles, manually recorded (at their convenience) the start ing and e ndin g times of thei r trips, p l us the distance traveledthe conventional way of gathering this type of data Completed validation test forms (Figure 8) were sent to CUTR for analysis, where average travel speed for the validation runs were compared with the output from the "SPEED.FXE" software for that specitlc trip Thirty runs produced comparative data by the end of the project. Since it was more convenient for City of Miami T ransportation P l anning staff to conduct validation runs during mid day rather than morning and afternoon periods, the F leet Director"' software was configured to p roduce two additional end-of-day reports: Figure 8 SAMPlE VALIDATION TEST FORM ., . ..,-'--:-""--:---------:-------.,:-:--..;::-----+ Begin Trlp:Time'< ..,----';..:.:..--'"----,-=-----''--"-'--'--''--'--'-""-""'--'----;."--Average T rip Speed: 22 'The Miami Merhod"


AVL for M

AVt. for Measurement of Corndor LOS Figure 9 DOLPHIN EXPRESSWAY-Peak Direction Eastbound, Sam-10am Average Link Speed (miles per hour) C> "' -C> -"' lolon. 25-Apr T ... 26-Apr Fri.29-Apr loloo. 2 -May Tue. 3 -May Wed. 11-May Thu. 12May Mon. 16May lu. 17-May Tbu, 19-May Frl20-May M on.2J. May Tue. 24-May Thu. 26-May Wed. l.Jun Mon. 6Jun Tua, 7.Jun Mon. JJ.Jun Tue. 14-Jun Wed. I!Nun Tue. 21-Jun Wed. 6-Jul 9 lOam Thu. 7-Jul Tue. 12Jul 8 9am Wed. 13-Jul -7am Fri. 15-Jul Tut. 19-Jul MMII!II!I 6 lam Tbu, 28-Jul C:=:::JI 5 6m Fri. 29-Jul Wed. Ill-Aug A., Fri. 12 AU1 VIed. 17-Aug


AVL for o f Corridor LOS CONCLUS I ON AND R ECOMMENDATION FOR fUTURE TESTS This evalu ation has clearl y d emo n stra ted t h at t h e AirTou ch Tdet rac a u tomatic veh icle location system can be used to measure avera ge vehicle speeds o n M iami's 1 7 tran sportation give n a cost sharing agreement with AirTouc h Teletrac, sufficien t electronic storage capacity, app r op ri ate data analysis software, and a p o o l of volu nteer dri vers. In fuct, a similar data gatheri n g experimen t could be repeated anywhere in the six metr o p o lit an a reas wher e AirTouc h Telet.rac i s available. To conduct a similar evalua tion o u tside the coverage areas o f those six metro a reas cities, ho wever, requires another A VL system ven do r using a different posi tion ing technology, most l i kely global posit i oning systems. In t he nex t phase of t hi s eval uat i on, CUTR will exten d the analysis u sing its program "SEGMENT.EXE" to compu t e average trip speeds for the entire corrido r for each o f Miami's 17 corrido r s in the peak d irection during the peak period. The City P lanni n g Divi s i on will then inco r po r a t e t hose comp ut e d average s peeds into its corridor le,el-of-service d eterminat i on. In addit ion, CUTR h opes to obt a in f r o m Dade County a l ink -node map of roadways annota ted with congested travel speeds, as calculated b}' the Florida Standard Urban Transportatio n Model St ructure (FSUTMS) simulation model T he congeste d travel speeds a nd resulting level-of-service determ in ati o n comp uted by thi s mo del are used as t h e official LOS values by t he F l o ri d a DOT, m e tropolitan planning organizations, and local governments in compl ying wit h t h e 198 5 Growth Management Act an d o t her transportation p l a nn i n g purposts. CUTR intends t o c ompare th e FSUTMS simulated v a lues of average travel for annota ted roa d li nks witl1 average speeds reported by t he Air T o uc h Tdetrac AVL system, w hich c a n b e accomplished sim ply by feedin g t h e l a t itu de and longitude coo r dinates f or those links into the "SEGMENT.EXE" p r o gr am. Accur a t e measur ement of average travel speeds needed f o r a variety of purposes, n o t just for determining conc urrency, as r e quired by the 1985 F l o ri d a Growth Management Act. Mobi l e s ou rce emission models use e stimated vehicle speeds i n d etermining regio n a l air quality, an impo r tant requirement of the 1990 Clean Air Act Amen dments. Additio n a ll y the Inter moda l Surface Tra n spo rtation an d Efficiency Act of 1991 (ISTEA) requires all ur b an areas w i th a pop u lation of more than 200,000 to establi sh a Congestion Management Syst em (CMS), inclu ding transportation perfon nance measures. CUTR and the Florida Department of Transportatio n are explori n g t he possi bility o f u sing t he same A VL system used in t his project to collect d ata need e d for traffic p erformance measures f o r one of the state' s two pro totype Congest i on Systems in Bro war d County o r Palm Beach County. TIJC Miami Method" 2 5


AVL for Measurement of Corridor LOS REFERENCES Air Touch Teletrac, "Corporate Fact Sheet" and "Fleet Director"'' Software Training Refe rence Guide January 1994. "Am tech to Install AVI for Surveillance on Houston Freeways," Inside !VHS, June 7, 1993. "A T/Comm's ETC Gets Commercial Debut on lllino i s Tollway," Inside !VHS, November 22, 1994. Barr ett, Lee, "How to Choose a n A VL System for Transi t B us, Rail &: Mo t orcoach," Metro Magazine, May/June 1994. Center for Urban Transportation Researc h, Roadwtry Ltvel-ofServiu Determination, Tampa FL, May 1991. Doering, Richard W., "Managing Traffic with RealTime Tra ns ponders," Civil Engineering Magazine, September 1994. Florida Highway System Plan: Level-of-Service Mamlfd, Florida Department ofTransportatio n Tallahas see, FL, May 1992. Gibbons, Glen, et at, "Automa tic Vehicle Location: GPS Meet s IVHS," GPS \Vo.r/d, April1993 IVHS America Legal Issues Committee, "Strrtwman" IVHS Privrlf)' Principles, lVHS America, Was hing ton, D .C., November 18, 1994. Levin e Steve Z and William R_ McCasland, "Monitor ing Freeway Traffic Conditions with Automatic Vehicle Identification Systems," ITE}oumal, March 1994. Tramportation Mening the Challenge of Growth Mtmagement m Miami, City o f Miami Department of Plann ing, Building and Zoning, Miami, FL, A u gust 1989. 26 .. The Miami Method"


Miami Tests AVL Data From Teletrac System For Measuring Traffic w ith j}(.nnissi(lfl fnmr In s ide rYHS 1 5 199 4 1994. Wotl is to pay two peop l e to dri\-e the (oad wirh a stop watch and a dipboard. But t h at' s no t p r ac tice for gathe r ing da t a on all $etwhethe.r there'$ a quik and inc:xpcnsivewaytofind o u t w h at t h eavcra gespciswereaaos s a netwcdc,'' l urner S'3.)'S. As f.u baGkas 1988, Turner began t hink in g aa a:ut omat i vehicle l ocation ( A Vl) Sfstc m migh t be tb eanswe; Bu t another si.'( yea .rs urwll t he Dep:mmcnt had the time and money to under take a t<:st. The city cont.r.lcted w i t h CUTR to pla.o. and oonductthe te$t and writ e an C\ .. .\Ju a t io n. The fidd trials began in Jate..,-\pril a nd were due to e.nd this week. GUTR willddive r afinal r ep o r t to t h e cit y in September P ietrzyk S:..y'3. The re$e archert :'l.l COT R c ho se Airt o uch (formerly Pactd ) Teletr a 1$ terrew i a l A Vl q$tCJ.n.atthe trackin g technology for the t est M i ami is-patt ofTdctrac s Sout h Florida mukct, one of six metr opolitan areas w her e the loglew o od, C-ilir. ;. flt tr,..ckiJIS sexvice bQsed on a proprietary radio loc at ion network, T dctra c'.s-o nhoar d units for ba.sicv e hick tracking sell for about $300; a $)'Hem t hat indudes a mobil e data ter mi nal cos t s a b out $ 600 to $80 0 ( ln>ide!VHS, ilpr;112 1993). Tel e tra e l ent th e proj ect 25 onboard unit$ a nd a trac k ing workstation c h arg ing CUTR c>nl y for the equ ip rnen t on volu nteen' vehicles. CUTR and the it y are n t P")'ing for the loation transml$don3, e i t her. {($all on tri al," s ays Stephen Tine m.'ln.<&er[ at Tdct rae's South Flo ri da offKc in Ft. Lauder d ale. Turn er recruited c-olleagues a nd friends to h.a''e the tri'lcking on their Focu$ing on five hour t each during AVL for Mcttsurcmr.. nt of Corridor LOS the mo r n ing and evening commute r pe3b, plu$ two houn on. S:tturda y, the it.y u.sed th e T e l c tr ae syrtcm to po ll the v ehicle$' locatio n s e very 3 0 The do'lta \9C()Sr'3ffit to detertui:ne One deri\'C.S theaYeragc tnwd speed for an entire trip, fro m r .hc t ime th e igni tion is turned on until th e moment it' s turned off. The othc:r correlates the geographic coordinucs-of toad m rl:l. evellicle$' .reCl)rded loc at iont to det ive speed$ for pruti<:ula r segments T c>tl ttermine if the syltem was produc ing valid da ta, C l ark and two other d r ivets in the p r o ject madc$ome. trips with a and clipboard to r ecord t heir tra\el times and odomete r rc.1.ding$. At. the $3me by the T ins the da t a lletttd m\ln u :tl l y, partkip;lnt$ findw far t hat tbed .itadc rived f rom t hcT detracS)ostcm i s ... acc u rate to a bout 2 mph for $pe<:d-that 's abo ut 1 0 Polk says. Ooc gap in t h e da t a collcctio o method u sed i.n rhe tes( is that the v oluntce.t driveN' regular trips don' t take them dO\\'n aJ11 7 trouuportation corri d ors w h ere t he city need; to c:.stabli$b average traveLspe-eds. to be dep l oyed on a wider l'd lik e t o see a more S)""Stemaric recruitment of drivers,'' Polk says. Tutnc:r p oinJs o u t, howcver,t h at rhcobjec.t of t h c text is not to develop a definiti v e database, but to de termine whether the technology i s an inexpensive and C:aS)' wa)' t o measure aYcra,sc If the ci ty were to imp l e m ent t he met h od t h e l ong t etm it woul d have toc.hoose its volunteers more .sd e cti vd)',and pos.sib l y provide ince ntiv es for people to do "auigned driving othe r theit norm:l.l he t a yl Purcha singunitsto insta ll on city-owned vehicles c-ould give th e De p a rt me nt a permanent set of prob for monitoring traffic Tine the city has expreu:: intere$t in retaining some o f the u , juas a Jlayi_I'IS customer Right now howev er, no funding is availab l e to con t inue co U ecting data beyond t h e test perid, Turn ersaf$ Onoe thedtyd ocu.meou has acco m plis h ed and m ake s $Orn e propo311.b, it m i g ht be abl e lO obt:ain :-!ddit ional f u n ds. Offic i al; with the: Flo rid a Depa rtment of Transportation (FDOT) havt-ex:presscd int erest conductingas imil ar t cstusingA VL ba.sed on c h e glol.xd po$iti oning sys t em (GPS), for t he of tompariton, be In o'lddicion to 3naty?.ing ltaffic-flo w for planning p urpo.scs-, a city C\ent u ally coul d U$C a n AVLbased ooJJe<:tion method to support t r affic management, Turner W ith enoush a{$ p er b;.ps h.uodtb-at probell, the cit)' oould cstablidl a data base: iJ.ldica(in g n o rmal traffic speed..s-on various Jinks. Using a progr<1m t o deri\e travel s poeds in tim e t he $f$\em eoul d detec t when traffi on a rOOdW:\y fell below an l!$tab1ished threshold, t hu s indiat ing incident. Also a na.lyz:ing bistorica. l traffic How data co uld hdppinpoint "choke points" where uaffic r :g\lbrly f.1ll.$ bdo w the thrhol d h e saf$. T raMpo r tatio n tmln

AVL for Mei!Surcmenr of Corridor LOS PROJECT CONTACTS: Clark P. Turner, AICP Transportation Planner City of Miami Department of Planning, Building and Zoning 275 N.W. 2nd Street, Miami, FL 33128 Tel : (305) 579-6086 Fax: (305) 358-1452 Michael C. Pietrzyk, P.E. Senior Research Associate and IVHS Program Manager Center for Urban Transportation Research College of Engineering, University of South Florida 4202 East Fowler Avenue, ENB 118, Tampa. FL 33620 Tel: (813} 974 Fax: (813) 974-5168 Stephen J. Tine Manager. Commercial Sales AirTouch Teletrac 3330 N.W. 53rd Street, Suite 302, Ft. Lauderdale, FL 33309 Tel : (305) 484-1300, Ext. 412 Fax: (305) 486