A study on delay of single-lane roundabout

Roundabouts are widely used in Europe, Australia and other countries. They work better than traffic signals at intersections with low and medium traffic volume and reduce the overall delay, better handle intersections with high volume of left turns. The purpose of this research is to validate Troutbeck's theoretic model by using field data in China. Circulating volume, entry volume, and entry delay are measured during peak and off-peak periods using video survey. Data on geometric design elements including circulating lane width, entry width, and roundabout diameter are measured through field survey. After surveying the actual traffic status of Fuming Square roundabout in Dalian, China, the theoretic delays of all approaches based on gap-accepted theory are calculated. We also calculate the mean delay of whole roundabout and compare it with the actual mean delay. The analytical results for traffic delays are validated via field data obtained from the single-lane roundabout. Finally the level of service of the roundabout is analyzed.