Work Zone Speed Limit Procedure

A procedure was developed for determining work zone speed limits usable during the design or construction phases of a roadway construction project. The procedure classifies work zones by the potential hazard present, as represented by the location of work activities or traffic controls in relation to the traveled way, instead of the prevailing speed of traffic. Research by others showed that accident rates increase with deviation from average speed. The most desirable work zone speed limit policy minimizes the increase in accident rate during the construction period. Accident and speed studies showed that the minimum increase in accident rate and speed variance occurred in work zones with a 16 km/h (10 mph) reduction in the work zone speed limit. In a follow-up study, the procedure was implemented on a trial basis in work zones with speed limits up to and including 105 km/h (65 mph). Research showed that the procedure was implementable and can be used to establish speed limits that maximize traffic safety in work zones. Guidelines were developed for implementing the procedure.