ITS Research Program, UW

Transit Vehicles as Probes:
The Use of Transit Vehicles for Travel Time Measures in Support of Performance Monitoring

Sponsors:

TransNow (U.S. Department of Transportation)
Washington State Department of Transportation

Description:

Travel time is the preferred measure for performance monitoring. Presently, a variety of techniques and technologies can be used to estimate travel time, each of which has various strengths and limitations. For this reason, "data fusion," the principle integration of multiple data perspectives is seen as a desirable way to estimate travel conditions.

In the TransNow component of this project, we will develop a methodology for using transit coaches as probe vehicles to estimate travel time in support of performance monitoring. In the parallel WSDOT component of this project, freeway travel times deriv ed from probe transit coaches will be compared to and integrated with travel time estimates obtained from both direct and derived speed measures taken with WSDOT freeway inductance loop sensors. In addtion, we will explore travel time estimates from tran sit vehicles on arterial routes.

The goal of the TransNow component of this project is to leverage an existing transit automatic vehicle location system (AVL), currently used primarily for command and control purposes, as an additional key data source in performance monitoring. The goal s of the WSDOT component of the project are to (1) understand the relationship between AVL probe vehicles and loop sensors time estimates with an eye toward fusing these two data sources to achive more accurate travel time measurements, and (2) explore th e possibility of using AVL data to estimate arterial travel times.

References:

"An Algorithm for Predicting the Arrival Time of Mass Transit Vehicles Using Automatic Vehicle Location Data," Z. Wall and D.J. Dailey, Proceedings of the Transportation Research Board Annual Meeting, Washington, DC, 10-14 January 1999.

Irregulary Sampled Transit Vehicles Used as a Probe Vehicle Traffic Sensor, D.J. Dailey and C. Elango, Final TransNow Report, March 1999.