Traffic Law Enforcement in Work Zones: Phase II Research

Abstract

NCHRP Project 3-80 was initiated to develop guidance on the effective use of traffic enforcement strategies in highway work zones. Traffic enforcement is viewed by many as one of the most effective means available for reducing speeding and other undesirable driving behaviors that compromise safety in a highway work zone. However, practices nationally vary widely on the enforcement strategies and philosophies used in work zones, the administrative mechanisms applied to establish and maintain a work zone enforcement program, payment methods for work zone enforcement efforts, techniques applied to supplement work zone enforcement, and public information dissemination practices employed to support work zone enforcement in a region. In this report, results are described of three research efforts performed to facilitate the development of guidance on this topic: 1) determination of whether driver opinions, perceptions, and behaviors related to the risk of violating traffic laws in work zones differ depending on whether work zone enforcement practices in a region are predominantly passive (positioned in the work zone with lights flashing to attract attention and reduce speeds) or active (pursuit of violators and issuance of citations); 2) determination of the effects of using an enforcement officer and vehicle in a traffic-calming (passive enforcement) mode upstream of work zones where traffic queues develop on the speed, deceleration, and erratic maneuvers of traffic approaching the traffic queue; and 3) a generalized economic analysis of the potential crash cost reductions associated with the provision of enforcement in work zones was undertaken to determine AADT thresholds at which the benefits of providing enforcement in work zones exceeds the costs of enforcement. With respect to the first point, these studies indicate that the use of passive enforcement does not significant degrade driver perceptions of enforcement or driver response to enforcement compared to active enforcement use. Next, studies of enforcement upstream of work zone traffic queues were somewhat inconclusive, and did not indicate a clear effect of having enforcement deployed in this manner. Finally, the analysis of work zone crash costs suggests that enforcement safety benefits outweigh the costs of deployment in daytime work zones on roadways exceeding 5000 to 20,000 vehicles per day (depending on hourly enforcement costs), and at nighttime work zones on roadways exceeding 20,000 to 65,000 vehicles per day.