Simulating transit priority: Continuous median lane roundabouts

This paper describes and analyses a layout and regulation, which provides 100 % bus priority and no delays for buses at small and medium sized roundabouts. The Continuous Median Lane Roundabout (CMLR) is designed specifically for bus rapid transit (BRT) or buses with high level of service (BHLS), where buses run in median exclusive lanes. In previous solutions, access to the roundabout circulating lanes from the general purpose approach lanes has been controlled by traffic signals. In the CMLR, give way signs within the roundabout control the two conflict points between buses in the median lanes and other vehicles in the circulating lanes. Microsimulations show that there is a large and unused potential for transit priority at roundabouts. Significant reductions in delays and emissions may be achieved.