Impacts of Night-Time Work-Zone Speed Restrictions on Freeway Speed Characteristics: A Case Study on Edmonton, Canada

Freeway work zone is considered as a potentially hazardous zone, which asks for special speed restriction to provide a relatively safe environment for road users and workers. However, the efficacy of speed limit reduction to bring about significant change in collective speed behavior on construction sites is yet to be determined. In this regard, this study aims at evaluating the change in freeway speed characteristics triggered by night-time work-zone (NWZ) speed restrictions from field observations. This study specifically incorporated average speed data from different freeway segments to determine speed characteristics and speed limit compliance in NWZs as well as NWZ adjacent locations at distinct speed limit conditions. An urban freeway in Edmonton, Alberta, Canada equipped with dual loop detectors at different sections of the road was utilized for this study purpose. In order to perform spatial and temporal speed analysis, the studied roadways stretch was divided into discrete segments containing a group of loop detector station in each segment. The findings from the analysis of obtaining speed characteristics around NWZs lead to state that the work zone speed restrictions had notable implications on construction zone as well as downstream speed behavior. Speed limit compliance analysis indicated a significant decrease in compliance on NWZs in compared to construction free period. Study findings were indicative to the requirement of detail speed characteristic study to determine the suitable speed limit for a particular construction zone.