An Investigation of the Performance of Roundabouts with Metering Signals

A major project was undertaken for VicRoads, the state transport authority in Victoria, to investigate the performance of roundabouts with metering signals in Melbourne, Australia. Five multi-lane roundabout sites were chosen for comprehensive surveys of traffic and driver behaviour at roundabouts with metering signals. The survey data included video recordings of driver gap acceptance behaviour, intersection turning movement volume counts, automated counting of circulating traffic, GPS-equipped floating car surveys, and metering signal timings. Using the survey data, the entering and circulating traffic characteristics were investigated at the controlling and metered roundabout approaches. These included queue lengths, delays and queue spacing on approach roads, critical gap and follow-up headways of entering drivers, bunching and headway distribution of circulating traffic as well as circulating vehicle speeds. This paper presents various aspects of data collection, analysis, and findings of the project.