Measuring Control Delay at Signalized Intersections

Abstract

This paper presents a new methodology to measure delay at signalized intersections using linearly referenced global positioning system data. The methodology can be used to evaluate new models that estimate control delay (which includes deceleration delay, stopped delay, and acceleration delay). The main components of delay were determined by analyzing the distance-time, speed-time, and acceleration-time diagrams of a travel time run. The procedure used speeds and forward and backward acceleration algorithms to detect critical delay points. The stopped delay versus control delay relationship was found to be linear. In contrast to other studies, it was found that such a relationship did not pass through the origin and that a deceleration-acceleration delay value had to be added to the stopped delay term to obtain control delay. It was also found that deceleration and acceleration lengths were much longer than others reported in the literature and that the percentage of the control delay that takes place after the signalized intersection stop bar is not negligible.