Effect of crosswalk location and pedestrian volume on entry capacity of roundabouts
At roundabout approaches, vehicles must yield to pedestrians who are using crosswalks. The presence of pedestrians using the crosswalk at a roundabout approach thus decreases the entry capacity of the approach. This research used a calibrated microscopic traffic simulation model to study the effect of crosswalk location and pedestrian volume on the capacity of a two-lane approach entering a two-lane roundabout. The simulation results show that (i) at the same pedestrian volume, the crosswalk located further upstream from the yield line causes a smaller magnitude of reduction in the entry capacity, but there is no significant change in the entry capacity when the crosswalk is beyond three car-length upstream from the yield line; (ii) for the same crosswalk location and conflicting volume, the entry capacity reduces with increasing pedestrian volume, but the marginal reduction diminishes with increasing pedestrian volume. Linear regression equations for entry capacity adjustment factor for pedestrians as a function of conflicting volume have been developed. The adjustment factors are found to be lower than the values provided by the Highway Capacity Manual 2010 which are based on research conducted in Germany.