Estimating Queue Dynamics and Delays at Signalized Intersections from Probe Vehicle Data

摘要

For signalized intersections, queue length is one of the most important performance measures. It has beena research topic for many years to estimate the average queue length of traffic signals using loop detectordata and signal timing information. This study is focused on estimating queue lengths and delays usingthe information provided by probe vehicles (time and space) in a queue at an isolated intersection for bothover-saturated and under-saturated conditions. Shock wave theory (i.e. the Lighthill-Whitham-Richardstheory) is used to estimate the evolution of the back of the queue over time and space from the event datagenerated when probe vehicles join the back of the queue. By using the probe vehicle information, ananalytical formulation was developed for determining the critical points required to create time-spacediagrams to characterize the queue dynamics. These critical points are used to estimate the queue lengthand delays. This formulation was tested on the data obtained from traffic simulation software VISSIM.Furthermore, as a performance measure, total delay for the analysis period is calculated. It has been foundthat the proposed formulation is useful in estimating the queue dynamics at signalized intersections inunder-saturated and over-saturated conditions.