Roundabouts in the United States

TRBs National Cooperative Highway Research Program (NCHRP) Report 572: Roundabouts in the United States explores methods of estimating the safety and operational impacts of roundabouts and examines updated design criteria for roundabouts. Also available are appendixes to the report, published as NCHRP Web-Only Document 94, which includes detailed reviews of the literature on safety performance and operational models, the master inventory of U.S. roundabouts assembled for this project, and the results of the statistical testing of various models.