Signals and Meters at Roundabouts

With the emergence of the modern roundabout as an effective form of traffic control in the United States, more and more information is needed when situations arise in which additional traffic control is required. The signalization and metering of roundabouts can relieve congestion during peak hours of the day as well as possibly provide safer access for pedestrians and cyclists. Although the signalization or metering of a roundabout may prove to be effective in solving access and congestion issues, it is not common in the United States and few have been installed. Of the roundabouts where signals or meters have been installed, these were done with little or no formal experience. With that in mind, a need exists for professionals to understand the basics of roundabout signalization and metering. Several tasks were accomplished to generate a set of guidelines, and upon completing these tasks several options for the signalization and metering of roundabouts were found, including options for means of control, time of operation, and approach control. Unbalanced flow and pedestrians are also discussed, since these have been found to be the reasons for most signalization or metering. Several existing signalized and metered roundabouts are detailed from current literature and survey responses and were compiled in a table as part of the guidelines. Using all of the information from survey responses and literature seven guidelines were established, including the following: • Observe and obtain data • Review data • Identify main concerns • Choose means of control • Choose time of operation • Choose approaches to control