Section Travel Time Estimation from Point Detection Data

Author(s): Oh, Jun-Seok; Jayakrishnan, R.; Recker, Will | Abstract: Despite recent development efforts in many other advanced traffic surveillance systems, inductance loops are still the most widely used traffic detectors. This paper points out the deficiency of point measurements obtained from loop detectors in estimating travel times under congested traffic conditions and proposes a theoretically sound and practically applicable travel time estimation algorithm that uses the same loop detector data. The main idea of the algorithm is based on the concept of section density that can be easily obtained by observing in-and-out traffic flows between two point detection stations, with careful correction for detector errors. Travel times estimated from the proposed method are compared to those of other methods via both simulated and real traffic data. While the method that estimates travel time based on spot speeds tends to underestimate section travel times due to its inability to capture traffic congestion between detector stations, the proposed section-density based method provides fairly accurate travel time estimates.