Measuring freeway travel times using existing detector infrastructure

The most important task of a traffic surveillance system is to reliably determine whether a facility is free flowing or congested. Conventional vehicle detectors are capable of monitoring discrete points along the roadway but do not provide information about conditions on the link between detectors. This information would be useful to the operating agencies for taking timely decisions in response to various delay causing events and hence reduce the resulting congestion of the system. This paper presents an approach that matches vehicle measurements between detector stations to provide information on the conditions in the link rather than relying on the point measurements from the detectors. This work reidentifies vehicle measurements using the existing loop detector infrastructure. Although the research uses loop detector data, it would be equally applicable to the data obtained from any other traffic detector that provides a reproducible vehicle feature.