Methodology for Control Delay Estimation Using New Algorithm for Critical Points Identification

Control delay, as a primary indicator of signalized intersection performance, is commonly estimated using analytical models due to difficulty of field measurements. This paper presents a new methodology for control delay estimation using vehicle speed profiles obtained by a global positioning system (GPS) device. An algorithm developed for critical delay points identification is based on threshold values of two parameters: average acceleration and deceleration rate, and a newly established parameter, phase duration. Based on the created algorithm, a five-step procedure is suggested for individual vehicle control delay calculation. The methodology was successfully tested on 112 sample runs at two signalized intersections. Detailed analysis of the acceleration and deceleration processes has shown that these two processes have different characteristics and effects on delay. In contrast to other studies, it was found that acceleration-deceleration delay depends on variation of acceleration delay and cannot be considered as constant. A slightly lower delay value was obtained by the suggested methodology, indicating that the new parameter could eliminate delay that is not affected by traffic signals.