Toward Roundabout Accessibility—Exploring the Operational Impact of Pedestrian Signalization Options at Modern Roundabouts

This paper explores the use of pedestrian signalization options for crosswalks at one- and two-lane roundabouts to enable these facilities to be accessible to pedestrians with vision impairments. Motivated by uncertainties about the safety of roundabouts for blind pedestrians, audible pedestrian signals hold promise for safely regulating the interaction of vehicles and pedestrians at these facilities. However, the use of pedestrian signals at roundabouts is controversial because of the potential for queue spillback into the circulating lane and delays to vehicular traffic. The objective of this work is to quantify pedestrian-induced delays and queuing impacts of a pedestrian signal placed at the busiest approach of a modern roundabout. The analysis is performed using a calibrated microsimulation model and includes assessment of innovative solutions for crossing geometry and phasing scheme at one-lane and two-lane roundabouts. The results suggest that the impact of pedestrian signals at roundabouts is greatest as vehicle volumes approach capacity, but that vehicle delay and queuing can be mitigated through innovative signal configurations. The findings are important in light of recent discourse concerning the accessibility of roundabouts to pedestrians with vision impairments that may ultimately move towards a requirement for signalization for certain facility types.