Abstract:
This research examined the operations of a four-legged, two-lane modern roundabout with different combinations of approach volumes. Because of the insufficient number of roundabouts to collect field data, experiments were performed with the VISSIM microscopic traffic simulation model. The model’s parameters were calibrated with real data collected at a four-legged, two-lane modern roundabout. Different combinations of approach volumes, which ranged from 400 to 1,600 vehicles per hour, were simulated to create relatively high or low traffic demand in one or two approaches. The performance of each roundabout approach was measured by average control delay and level of service. The results of the experiments highlight the potential operational issues of four-legged, two-lane modern roundabouts. The results are presented in three charts that may serve as a quick reference guide for engineers to determine whether a roundabout is a feasible type of intersection control for a given set of design volumes before in-depth engineering analysis is performed.
