ENGINEERING STRATEGIES FOR SPEED REDUCTION AND SAFETY ON HORIZONTAL HIGHWAY CURVES

Abstract

Excessive traffic speed is a significant factor in crashes on curves as well as in the severity of these crashes. Excessive speeds reduce a driver’s ability to react and maneuver and requires greater stopping distances. This research work establishes a technical procedure to effectively manage speeds as well as ways of decreasing crashes on horizontal highway curves thus ensuring safety. In conducting this research, five (5) case studies of different existing accident-prone horizontal highway curves were considered. The four (4) highway routes that were considered as case studies are: Warri-Agbor road in Delta State, Oka-Ishua road in Ondo State, Ado-Ilawe and Ado-Iyin roads both in Ekiti State. Case studies were chosen on the basis of the incessant rate of road traffic crashes on them and data for this study were obtained from field observations and measurements. The obtained geometric data were checked with appropriate standards to determine the geometric shortcoming and consequent causes of crashes. The spot speed method was used to obtain the speeds of vehicles and the curves were designed with the eighty fifth percentile speeds and appropriate sight distances were introduced