September 2007

Technology Overview

Image shows real-time AVL communications using wireless network for GPS. A GPS satellite relays the position of the bus equipped with an odometer gyroscope to a communications center. The dispatch system at the communications center distributes information to other systems (shown are customer assistance, planning and scheduling, and operations analysis).

Illustration of AVL and real-time communication network.
(Source: Automatic Vehicle Location Successful Transit Applications)

Use AVL to:

Improve bus on-time performance and service efficiency
Reduce passenger wait time
Provide customers with real-time service information
Enhance on-board safety
Improve response times to incidents and emergencies
Improve communications between supervisors, dispatchers, and operators
Plan schedules and routes

Automatic Vehicle Location (AVL) systems calculate the real-time location of any vehicle equipped with a Global Positioning Satellites (GPS) receiver or other type of receiver-transmitter location technology. Data are then transmitted to a transit center through radio or cellular communications. The AVL information may be used immediately to correct scheduling and other operational deviations and also archived and used for schedule and route planning, reporting, and performance analysis.

AVL systems span a wide range of costs and levels of sophistication. Small fixed route bus agencies with less than 100 vehicles or agencies on limited technology budgets can consider web-based, off-the-shelf systems for real-time fleet location monitoring. Comprehensive, customized integration of AVL with other systems is most appropriate for large fixed-route bus agencies.