California Partners for Advanced Transportation Technology

From an operations standpoint, the most important task of a traffic surveillance system is determining reliably whether the facility is free flowing or congested. The second most important task is responding rapidly when the facility becomes congested. Other tasks, such as quantifying the magnitude of congestion, are desirable, but tertiary. To address the first two tasks, this paper presents a new approach for traffic surveillance using existing detectors. Rather than expending a considerable effort to detect congested conditions, the research employs a relatively simple strategy to look for free flow traffic. The work should prove beneficial for traffic management and traveler information applications and it promises to be deployable in the short term. Keywords: traffic surveillance, loop detectors, travel time measurement, vehicle reidentification, Congested traffic