Estimating Queue Dynamics at Signalized Intersections from Probe Vehicle Data

As vehicle-to-vehicle and vehicle-to-infrastructure communications technologies are evolving, data from vehicles equipped with location and wireless technologies provide new opportunities to observe traffic flow dynamics more precisely. A new methodology is presented for estimating the dynamics of vehicular queues at signalized intersections on the basis of the event data generated by probe vehicles. The methodology uses shock wave theory (i.e., the Lighthill–Whitham–Richards theory) to estimate the evolution of the back of the queue over time and space from the event data generated when probe vehicles join the back of the queue. The time and space coordinates of these events are used to develop a formulation for determining the critical points needed to create time–space diagrams or shock waves to characterize the queue dynamics. The methodology is applied to sample data generated from the microscopic traffic simulation software VISSIM. It is found that the proposed methodology is effective in estimating queue dynamics at traffic signals.