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(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.03 [I] -3 3 Stars All All Not Specified All

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

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.56 [B] 44 5 Stars All All Not Specified All
0.18 [B] 82 5 Stars All A,B,C Not Specified All
0.29 [B] 71 5 Stars All All Not Specified Rural
0.13 [B] 87 5 Stars All A,B,C Not Specified Rural
0.71 [B] 29 4 Stars All All Not Specified Urban
0.19 [B] 81 4 Stars All A,B,C Not Specified Urban
0.61 [B] 39 4 Stars All All Not Specified Urban
0.22 [B] 78 4 Stars All A,B,C Not Specified Urban
0.88 [I] 12 3 Stars All All Not Specified Urban
0.68 [B] 32 4 Stars All All Not Specified Suburban
0.29 [B] 71 4 Stars All A,B,C Not Specified Suburban
0.22 [B] 78 4 Stars All All Not Specified Suburban
0.22 [B] 78 4 Stars All A,B,C Not Specified Suburban
0.81 [B] 19 3 Stars All All Not Specified Suburban
0.32 [B] 68 4 Stars All A,B,C Not Specified Suburban

Countermeasure: Convert signalized intersection to modern roundabout

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.99 [B] 1 3 Stars All All Not Specified Urban
0.4 [B] 60 4 Stars All A,B,C Not Specified Urban
0.33 [B] 67 4 Stars All All Not Specified Suburban
0.52 [B] 48 4 Stars All All Not Specified All
0.22 [B] 78 4 Stars All A,B,C Not Specified All