Citation

Jiang Y. J. Transp. Res. Forum 2001; 40(4): 65-81.

Copyright

(Copyright © 2001, Transportation Research Forum)

DOI

unavailable

PMID

unavailable

Abstract

In order to efficiently plan and schedule work zone operations, it is essential to accurately estimate traffic delays. This article presents the results of a study on traffic delays at work zones on Indiana freeways. The equations for calculating various components of traffic delays are described and the applications of these equations are illustrated. Traffic delays at a work zones can be caused by deceleration while approaching the work zone, reduced vehicle speed through the area, and time needed for vehicles to resume freeway speed after exiting the vehicle queues. Delay equations were developed in this study when arrival traffic flow is above the work zone capacity and below it. In calculating traffic delays, the vehicle queue-discharge rates, instead of the work zone capacity, should be used because the queue-discharge rates are lower than the work zone capacity. Equations related to individual vehicle queues were also developed to estimate the queue lengths, the time needed to clear vehicles from a queue, and the total and average traffic delays of a queue. The quantities of these vehicle queue attributes can be used to display real-time traffic information on message signs to inform motorists of expected delays or for adaptive traffic controls at work zones.