Vehicle Speed Impact on the Design of Efficient Urban Single-Lane Roundabouts

Abstract

Implementing effective roundabouts in urban areas is a highly demanding task and requires optimizing traffic (operational) efficiency (TE) and traffic safety (TS) while considering geometric factors, traffic characteristics and local constraints. To capture a relationship between roundabout design elements, traffic demand flow and vehicle path speed through the roundabout, we studied American and Australian method on four urban single-lane roundabouts located in the Croatian capital of Zagreb. Comparison between design speed and measured vehicle speed show bigger deviations than previous studies. Preliminary validation of the used methods enables better understanding of its application for Croatian conditions. These preliminary results suggest that the used methods can capture the correlation between geometry, traffic flow demand and vehicle speed of urban single-lane roundabouts but with needed calibration for local conditions.