Using GPS to Measure Traffic System Performance

Traffic system performance can be measured in various ways, but from the user perspective, congestion is the major criterion. This article examines some novel uses of GPS in the measurement of vehicle speeds and travel times and their synthesis into measures of congestion and ultimately of the performance of the urban road system. The article also will discuss the integration of GPS-based congestion measures into an ITS framework, techniques for implementing a congestion-monitoring system, and implications for urban road system planners, managers, and users.