Estimation of Traffic Delays and Vehicle Queues at Freeway Work Zones

The traffic flow is disrupted and delayed at a work zone because the traffic capacity and the vehicle speed are lower at the work zone section than at other portions of the roadway. Traffic delays at a work zone include delays caused by deceleration of vehicles while approaching the work zone, reduced vehicle speed through the work zone, time needed for vehicles to resume freeway speed after exiting the work zone, and vehicle queues formed at the work zone. Delay equations were developed in this study for both when arrival traffic flow is above the work zone capacity and below it. In addition to equations of work zone traffic delays, several equations of the characteristics of individual vehicle queues were also developed. These equations can be used to estimate the maximum and average queue lengths of a vehicle queue for a given time period, the time needed to clear individual vehicles from a vehicle queue, and the total and average traffic delays of a vehicle queue.