Safety and Operational Performance of Roundabouts

Abstract

When there are two or more roads meet, there is higher tendency of conflicts among vehicles. Roundabout is not a new concept to manage conflict points at at-grade intersection. However, improper motorist behaviours especially during peak hour affect safety and operational performance of a roundabout. This paper compares the safety and operational performance evaluation of a conventional non-signalized roundabout and a conventional signalised roundabout and explores the potential of turbo roundabout to replace the conventional ones. Three characteristics used to evaluate safety performance of the roundabouts include entry lane selection, use of entry and exit indicators, and weaving activities. These behaviours create the possibility of conflict, hence, risk of fatalities. On the other hand, delay and total time travel are used as indicators of operational performance of the roundabouts. We used SIDRA INTERSECTION Software to determine the theoretical delays and Level of Services. High delay, a time factor, affects motorists’ emotion, might have contributed to the safety performance. Similarly, motorists’ non-compliance behaviours affected the operational performance.