Study Details

Study Title: NCHRP Report 572: Applying Roundabouts in the United States

Authors: Rodegerdts et al.

Publication Date: 2007

Abstract: Based on a comprehensive evaluation of roundabouts in the United States, this report presents methods of estimating the safety and operational impacts of roundabouts and updates design criteria for them. The report will be useful to geometric designers and traffic engineers who are considering improvements to an intersection. Presentation materials that may be helpful in public meetings and similar forums are available on the TRB website (http://www.trb.org/news/blurb_detail.asp?id=7086).

Study Citation: Rodegerdts, L. A., Blogg, M., Wemple, E., Myers, E., Kyte, M., Dixon, M., List, G., Flannery, A., Troutbeck, R., Brilon, W., Wu, N., Persaud, B., Lyon, C., Harkey, D., and Carter, D., "NCHRP Report 572: Applying Roundabouts in the United States." Washington, D.C., Transportation Research Board, National Research Council, (2007)

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Intersection geometry

Countermeasure: Convert all-way, stop-controlled intersection to roundabout

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
1.03[I]-32 StarsAllAllNot SpecifiedAll

Countermeasure: Convert intersection with minor-road stop control to modern roundabout

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.56[B]443 StarsAllAllNot SpecifiedAll
0.18[B]823 StarsAllA,B,CNot SpecifiedAll
0.29[B]713 StarsAllAllNot SpecifiedRural
0.13[B]873 StarsAllA,B,CNot SpecifiedRural
0.71[B]293 StarsAllAllNot SpecifiedUrban
0.19[B]813 StarsAllA,B,CNot SpecifiedUrban
0.61[B]393 StarsAllAllNot SpecifiedUrban
0.22[B]783 StarsAllA,B,CNot SpecifiedUrban
0.88[I]122 StarsAllAllNot SpecifiedUrban
0.68[B]323 StarsAllAllNot SpecifiedSuburban
0.29[B]713 StarsAllA,B,CNot SpecifiedSuburban
0.22[B]783 StarsAllAllNot SpecifiedSuburban
0.22[B]783 StarsAllA,B,CNot SpecifiedSuburban
0.81[B]193 StarsAllAllNot SpecifiedSuburban
0.32[B]683 StarsAllA,B,CNot SpecifiedSuburban

Countermeasure: Convert signalized intersection to modern roundabout

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.99[B]12 StarsAllAllNot SpecifiedUrban
0.4[B]603 StarsAllA,B,CNot SpecifiedUrban
0.33[B]673 StarsAllAllNot SpecifiedSuburban
0.52[B]483 StarsAllAllNot SpecifiedAll
0.22[B]783 StarsAllA,B,CNot SpecifiedAll