Increasing integration between AVL systems, components, and interfaces has improved the ability of transit agencies to collect data on location and schedule adherence; support operational control, service restoration, and planning activities.
Date Posted

AVL Systems for Bus Transit: Update (TCRP Synthesis 73)

Summary Information

This research documented the current state-of-practice of fixed-route and demand responsive automatic vehicle location (AVL) systems. A literature review was conducted and the results of on-line surveys and case study telephone interviews were evaluated to collect information on the characteristics of implemented bus AVL systems, and examine agency experiences during the design, procurement, implementation, and integration of these systems.

Using an on-line survey software tool, questionnaires were distributed to 107 different transit agencies in the United States and Internationally. Thirty-two (32) agencies responded to the survey. Researchers consolidated participant responses to each of the survey questions and highlighted important findings documenting benefits, costs, and lessons learned.

Follow-up case study telephone interviews were conducted to obtain additional details on selected systems. Experienced staff (1 to 2 persons) from each from each of the following agencies provided comments. The selected agencies provided for a broad range of diversity in terms of geographic location, fleet size, systems integrator, and AVL system functionality.

  • Beaver County Transit Authority (BCTA) in Rochester, Pennsylvania (Pittsburgh region)
  • King County Metro in Seattle, Washington
  • Triangle Transit Authority in Raleigh–Durham, North Carolina
  • Valley Metro in Phoenix, Arizona


Although the basic system architecture of bus AVL systems has not changed much over the past 10 years, the degree of functionality and reliability of these systems has increased remarkably. With increased integration between components, systems, and interfaces, current bus AVL systems have more options and functionality associated with the core location tracking function. The core function generally includes the central software used for operations management and the onboard GPS, computers, and communications equipment required for real-time location of feet vehicles. Additional functional options can include schedule adherence monitoring, onboard mobile data terminals, managed voice communications, security monitoring, text messaging, dead reckoning devices, next stop announcements, monitoring of vehicle mechanical status, automatic passenger counting, and support a wide array of real-time transit traveler information systems.

Technologies commonly cited as effective included those that collect data on location and schedule adherence, and support operational control, service restoration, and planning activities. Overall, the benefits data cited were anecdotal in nature.

In follow-up telephone interviews with the BCTA which supports AVL on 32 vehicles the following benefits were noted:

  • Dispatchers have an improved ability to easily know where fleet vehicles are at all times.
  • Customer service staff informs callers of the current location for their bus, and use the playback feature to investigate the validity of complaints.
  • Planners use the data on actual running times and dwell times to justify changes that have made schedules more realistic and effective.
  • The transfer center arrival prediction dynamic message sings (DMS) are popular with customers, in particular during the area’s harsh winters; these DMSs are located within the transfer center interiors and thus provide information while allowing passengers to wait inside.

In follow-up telephone interview with the King County Metro which operates the ACCESS paratransit service on approximately 290 vehicles, the following benefits were noted:

  • Adding mobile data terminal (MDT) units to the exiting AVL system enabled manifests to be downloaded and updated, trip events completion data to be monitored in real time, and text messaging to be made available between operators and dispatch. ACCESS management indicated that after the MDT features were activated, productivity increased from about 1.6 to about 1.7 passengers per vehicle hour. A large portion of the increase was attributed to the addition of MDT units.

The following summary information, excerpted from the report, summarized the benefits of bus AVL applied to fixed-route and paratransit operations.

Fixed-route Operations

  • AVL software provides improved situational awareness and additional voice communications management capabilities for dispatchers, expanding the size of the fleet that can be handled by each dispatcher.
  • Schedule adherence feedback to dispatch, operators, and supervisors helps to maximize on-time performance and reliability.
  • Dispatchers and supervisors can be proactive in addressing operational issues, including more timely and effective reaction to service disruptions.
  • Text messaging can improve dispatch efficiency and provide clearer messages in distributing information to operators.
  • Covert alarm monitoring supports the ability of operators to quickly inform dispatch about an onboard emergency and for dispatch to immediately know the vehicle location to send assistance.
  • Single point for operator login to all onboard equipment reduces the potential for inaccurate login, maximizing the accuracy of schedule adherence, headsigns, and farebox data.
  • Automated next stop announcements provide consistent announcements for passengers, reduce operator workload so they can focus on safe vehicle operation, and help address the requirements of the Americans with Disabilities Act.
  • Automatic passenger counter equipment allows for the cost-effective collection of comprehensive passenger boarding and alighting data with consistent reliability, relative to the use of human ridecheckers.
  • The system can provide real-time next bus predictions to customers both pretrip and enroute, which can help increase ridership by reducing customer anxiety, enhancing perceived reliability, and generally presenting a more "modern" image (in particular among "choice" riders).
  • More comprehensive historical data collection and incident reporting allows more effective and detailed analysis (e.g., for Planning to use historical schedule adherence data to develop schedule adjustments).

Paratransit Operations

  • Electronic manifests and trip completion data reduce operator workload and provide more accurate and consistent data.
  • Real-time fleet location data further improve the ability of scheduling software to enhance vehicle productivity and accomplish meets with fixed-route service.
  • Onboard navigation assistance aids operators in keeping on schedule with their manifests, in particular with newer operators who are less familiar with local streets.
  • For the TriMet AVL system (Portland, Oregon):
    • Improved availability of real-time information for dispatchers could reduce running times by an average of 1.45 min/trip and reduce average passenger waiting time at the stop by 0.11 min.
    • Depending on the assumptions regarding reduced wait times and reduced wait time uncertainty, the number of annual transit trips with Transit Tracker information by means of the Internet needed for positive net benefits could range from approximately 200,000 to 900,000.
  • For the COTA AVL system (Columbus, Ohio), with changes in dispatcher workflow the observed overall effect was of saving nearly three hours in the time required for daily work. It was projected that a fleet size increase of up to 10 percent could be accommodated with the current complement of dispatchers.
  • For the Delaware First State AVL system, roughly $2.3 million in annual benefits were estimated as reasonably attributed to the implementation of the system.
Deployment Locations