Traffic Control at Freeway Work Sites

Abstract

A comprehensive, multidisciplinary study of traffic control needs of freeway lane closures at work zones included surveys of drivers and highway patrolmen, test driver studies, field measurements of merging and speed characteristics, a digital simulation study, and the field testing of novel signs. Construction accident data, collected on a turnpike facility, was dominated by collisions with objects, many involving trucks at night in the transition area at crossovers. Rear‐end accidents resulted in higher injury rates than other accidents, most occurring in the closed lane or bidirectional area. The simulation study indicated that potential problems increase rapidly as approach volumes increase toward open‐lane capacity, but these problems can be greatly reduced if closed lane drivers can be induced to initiate early merges. Several signs designed to influence driver behavior were field tested. The results were largely inconclusive, but the “Merge Soon With Caution” sign was found to increase early merge frequencies. It is recommended that developers of traffic control plans emphasize methods to encourage early merges where higher volumes are expected.