Services and Technologies

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Simple AVL systems are implemented throughout the United States, Western Europe and in South East Asia. Comprehensive AVL systems are being implemented on a limited basis in the United States and Western Europe. However, comprehensive AVL systems are being increasingly deployed.

In the United States, a recent study has identified at least 61 transit agencies with operational AVL systems. A hundred others are in the planning or implementation stages. The locations of operational systems are indicated on the map (below). For identification of these transit agencies, as well as those in the planning or implementation stages, see the report Advanced Public Transportation Systems Deployment in the United States—Update January 1999, referenced at the end of this document.

Table 1 describes the different types of AVL technologies employed or in planning for differrent types of service in the United States.

Table 1: AVL deployment in the United States, January 1999

FR= Fixed Route; DR= Demand Response; LR= Light Rail; HR= Heavy Rail;
CR= Commuter Rail; FB= Ferry Boat; AG= Automated Guideway; MR= Monorail.
Source: Advanced Public Transportation Systems Deployment in the United States—Update January 1999, FTA.


Most of the following case studies are US-based and are excerpted from Advanced Public Transportation Systems, The State of the Art Update of '98 (ITS JPO, January 1998). For more examples of the use of AVL please refer to this document.

Signpost/odometer systems


Newark, New Jersey
New Jersey Transit (NJT) is implementing a new signpost and odometer system. The system will operate primarily in Essex County (Newark area), although all of their buses are equipped with the requisite hardware and software. Hardware implementation is about complete, including on -board equipment on all buses and signposts at every garage, at strategic places in Essex County, and at the Port Authority Bus Terminal in New York City, the terminus of many of their routes. NJT is now in the process of inputting all route data into the central computer and training their dispatchers on the use of the system. NJT notes that the software capabilities are now catching up to the hardware which has been available for a number of years. NJT is implementing the AVL system in order to better manage their bus operations.


Seattle, Washington
King County Metro has had an operational signpost and odometer AVL system on all of its buses since 1993. Original system cost was about $15 million. The system includes computer -assisted dispatching. Each bus has a mobile data unit (MDU) and silent alarm for the driver. Over the last two years, the AVL has been linked to automatic passenger counters, which Metro has been operating on 12 percent of its buses since 1980 (see Section 2.4). Previously, the APCs had their own location equipment. Now, the bus’ MDUs are capable of feeding bus location information directly to the APCs, eliminating the need for a separate signpost network. The AVL also provides the information for “Bus View,” a real-time passenger information system on the Internet (see Section 3.1) Bus View gives, in text form, bus schedules and vehicle status. Metro is also upgrading the CAD and AVL software, and is to have this completed by early 1998. Future system enhancements may include links to smart card readers on the buses, electronic fareboxes, electronic destination signs, and automatic vehicle identification tags. Metro cites th e benefits of AVL as an increased availability of operations data, a greater ability to respond to service disruptions and emergencies, and the ability to offer transfer protection to their riders.


Westchester County, New York
The Westchester County DOT (White Plains area) has been operating a signpost and odometer AVL system, including a silent alarm for the driver, on most of their 332 buses since 1983. The system has served the agency quite well, but the agency feels it is time to replace the system. The DOT has hired a consultant to conduct a review of the current conditions and interview th e personnel working on the AVL system. They expect to complete a system design by the end of 1997 and release a request for proposals sometime in the second quarter of 1998. The new system will (most likely) be GPS- based and will be designed to link into their two-way communications and the bus’ “black box” (destination sign, farebox, etc.).


Norfolk, Virginia
Managing a fleet of 151 vehicles, Tidewater Regional Transit (TRT) elected to use a signpost/odometer AVL system in 1991. Their current system requests information from each vehicle in 40-second intervals. The system provides real-time information and provides more accurate schedules. TRT also added the silent alarm capability to the AVL system and vehicle condition monitoring sensors. TRT has benefited in lower rider complaints and an improved ability to respond to complaints.

GPS Systems


Portland, Oregon
The Tri-County Metropolitan Transportation District of Oregon (Tri-Met) is just finishin g installation of a GPS AVL system. All 640 of its fixed-route vehicles are equipped, and installation on its 140 paratransit vehicles, begun in September 1997, was to be complete within two months. Although they have not reached final acceptance, the fixed-route fleet is being dispatched using the AVL. The system also includes APCs (see Section 2.4) and real-time information for telephon e operators to respond to passenger inquiries. (Future plans call for providing the real-time information directly to the public, without the need for a human interface.) Three pilot tests of preferentia l treatment have been conducted and is now scheduled for permanent installation in a fifteen mile corridor. (Early buses will not receive preferential treatment.) The AVL is part of a regional ITS system, which is proceeding. Transit buses will be used as probes for traffic monitoring, and the highway department will provide the traffic information back to Tri-Met.


Denver, Colorado
The Regional Transportation District (RTD) has had an operational AVL system on all of its 900 buses since the end of 1995. AVL data are also used to post real-time departure information onsigns at the two Mall stations, downtown. The system, which cost about $11 million, includes an extensive computer-aided dispatch syst em. RTD feels that the AVL system gives them better control of the fleet, while freeing a number of on-street supervisors for other important duties. Schedule adherence is improved since the installation of AVL. Disabled buses can be located and serviced much more quickly. Also, one fewer person is necessary at the downtown Mall stations where many of their routes terminate.

The agency also believe s that AVL greatly heightens passenger safety. Police are now much more willing and able to respond to emergencies on buses, because the bus now can be located to within a few feet. Prior to the implementation of AVL, it could take a long time to locate the bus if it was off-route. In one situation, AVL greatly assisted RTD and the police in re-uniting a mother with her child which she had left behind on a bus.

Future plans center around use and dissemination of the bus location data. RTD is not currently using the schedule adherence function, nor are the AVL data being used by the scheduling department. This will happen when the schedule adherence function is working satisfactorily.

Current plans are to put passenger information data on the Internet. Additionally, there are information kiosks around the city, which may be fed AVL information in the future. Finally, there are plans to transmit the data to the Colorado DOT Traffic Operations Center for intermodal coordination of transportation in the region.17


Atlanta, Georgia
The Metropolitan Atlanta Rapid Transit Authority’s (MARTA) ITS system received fina l acceptance on March 30, 1997. Of the system’s 750 buses, 250 are equipped with AVL. The system is linked to the Georgia DOT’s traffic management center for inter-agency cooperation. Also, 15 buses are currently equipped with automatic passenger counters, and 60 more will be added in the near future (see Section 2.4). Some of the buses are equipped with on-board annunciators (automatically actuated by the AVL), and there are electronic signs at a few bus stops and monitors at some bus-rail transfer stations. Although the real-time bus location information is not yet fed into the many electronic passenger information kiosks around the city, they are hoping to do this soon.

MARTA is pleased wit h its AVL system and notes concrete benefits. They believe they can more effectively improve on- time performance with the greater information AVL provides. Another benefit is greater safety. For example, when an off-route bus had an accident, the dispatcher sent assistance directly to the bus’ current location, even though the driver had identified the bus as still being on-route. Another instance involved a bus, making the last trip of the night from a rail station, left before its scheduled time. The dispatcher saw that the bus had left too early, and called it back to the rail station, so that the passengers exiting the train would not be stranded.


New York City, New York
In October 1996, New York City Transit (NYCT) awarded a contract for an 18-month demonstration project of an AVL system. The New York City environment also provides extremely heavy ridership, headwa y variability, and bus bunching, all of which have to be addressed in system design, installation, training, and operation. As of September 1997, the project had passed the critical design phase and had begun the construction and installation phase. The AVL will locate primarily by GPS, but will also rely heavily on interpolations between GPS signal receptions with dead -reckoning, due to the challenging environment of New York City. Tall buildings lining both sides of most streets make it difficult to obtain GPS signals, making position determinations by GPS less frequent.

Approximately 170 buses from the 126th Street depot in Manhattan will be equipped with differential GPS receivers and dead-reckoning technology, connected to mobile data terminals (from which the driver will receive information). Anticipated accuracy of the vehicle location is about ten meters. The on-board processor (vehicle logic unit) will store uploaded schedule information and will use time and locatio nal data to compute schedule adherence for both the driver and the dispatch center. Problems will be transmitted on an exception basis. However, a default polling interval of 40 seconds wi ll be used to provide the timely vehicle location data required by the custome r information system that is being developed simultaneously (see Section 3.2). Drivers will use a soft key vehicle control head to communicate both digital messages and requests to make voice contact over the upgraded 800 MHz radio network. Radio system upgrades include de-trunking of five of their 15 channels to provide dedicated channels for transmission of AVL data to the related CAD system (see Section 2.5.1). Archival data and reports will be used to optimize routes, schedules, and operations.

Dead Reckoning combined with another technology


Chicago, Illinois
CTA has a fleet of 2080 buses, which will all be AVL enabled. The system of choice for CTA is dead reckoning working alongside a GPS system. Both systems will transmit location information but one system will compensate for the other when a bus reaches an area where service for one system is interrupted. Tall buildings and underpasses made dead reckoning a viable complementary addition to GPS. The combination of the two systems also permits a high degree of accuracy in locating vehicles. 


Houston, Texas
The Metropolitan Transit Authority (Metro) is planning to procure a full AVL system for all the vehicles it operates - 1,200 fixed-route buses, 153 demand-response vehicles, 154 police cars, 4 motorcycles, and 263 support vehicles. Previously, they awarded a $22 million contract for th e communications backbone, complete with a new radio system, and a vehicle area network, which complies with the J1708 standard, for their buses. (The installation of this backbone was to b e complete by January 1998.) The desired location method “is specified as dead-reckonin g supplemented with another proven location technology. Final determination of the ‘other’ [location technology] has not been made.”

The communications backbone is designed to support several other APTS applications. The base system will be linked to both the electronic farebox and the destination signs on the exterior of the bus. In addition, there is funding in place for the procurement of approximately 250 automatic passenger counters. Possible future additions to the system include annunciators and remote engine monitoring.

Ground-based Radio


Rochester, Pennsylvania
Beaver County Transit Authority uses a Motorola Loran-C system for 13 out of 36 buses in its fleet. The Loran-C system has resulted in better on-time performance and less rider complaints. BCTA installed Loran-C in 1991 and will now become a National Pilot Site for a Mobility Manager, which will update their AVL to a GPS enabled AVL system. 


Santa Monica, California
The Santa Monica Municipal Bus Lines continues to employ an alternative form of vehicle location. As described in Update ‘96, the agency has had the AVL system in regular operation since October 1992. For $130,000, the agency purchased a workstation equipped with a modem, an electronic map with a detailed database of the streets and addresses in the Los Angeles area, and communications and control software. Buses are located by using a network of transmitting and receiving antennas.


The agency’s workstation communicates with the control center through standard telephone lines, and the agency pays a monthly subscription fee, based partly on the amount of time its workstation is connected to the central computer. The agency does not connect their workstation to the central computer too often, because the cost would be prohibitive. The AVL, therefore, does not operate in real-time. Santa Monica Municipal Bus Lines uses the information for planning and problem investigation only.

This report excerpted several segments from references 1, 3 and 5.

1. Advanced Public Transportation Systems Deployment in the United States - Update January 1999, Volpe National Transportation Systems Center for the Federal Transit Administration, January 1999, FTA-MA-26-7007-99-1, DOT-VNTSC-FTA-99-1; EDL number 8165.


2. Advanced Public Transportation Systems, The State of the Art Update of '98; ITS JPO, January 1998.


3. Automatic Vehicle Location Successful Transit Applications, A Cross-Cutting Study; ITS JPO August 2000.


4. Chira-Chavala, T., David Gillen, Lee Klieman, Amy Marshall, Bus Operations in Santa Clara County, Potential Uses of AVL, and Framework for Evaluating Control Strategies, California PATH, July 1999. Chapter 5 of this report is a stand-alone document outlining a framework for the evaluation of the benefits and costs of AVL.

5. Gillen, David, Elva Chang, Doug Johnson, Productivity Benefits and Cost Efficiencies from ITS Applications to Public Transit: The Evaluation of AVL, California PATH, September 2000.


6. Okunieff, Paula E., Synthesis of Transit Practice 24: AVL Systems for Bus Transit, Transportation research Board, National Academy Press, Washington, 1997

7. Skomal, Edward, The Effects of AVL Accuracy Upon Public Service Bus System Performance, Journal of Advanced Transportation, (1984) 18:3, pp. 259-277

8. Tellechea, Suzanne, AVL Planning for the Winston-Salem mobility Manager (paper presented at the 1998 Annual meeting of the Transportation research Board, Washington, DC 1998)


9. US Department of Transportation, Advanced Public Transportation Systems: Evaluation Guidelines, January 1994 (Office of Technical Assistance and Safety) DOT-T-94-10


10. ESA Article: Why Europe Needs Galileo

Author: Dimitri Loukakos.  Last update: 02/09/01
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