Study Details

Study Title: Evaluation of Roundabouts on High-Speed Roadways

Authors: Bagley, D.L.

Publication Date: JAN, 2020

Abstract: All of the roundabouts included in this study effort were located in rural areas and were converted from minor road stop-controlled intersections. Additionally, all of the roundabouts in the study were single lane and had at least one leg with an approaching speed limit of 55 mph. The included roundabouts had inscribed circle diameters between 100 and 160 feet and had an average major road volume of 6,000 AADT and an average minor road volume of 3,600 AADT. The Empirical Bayes methodology was utilized to provide a more robust statistical analysis of the data. The purpose of the evaluation is to measure changes in total intersection crashes, fatal and injury crashes, and frontal impact crashes after intersections were converted to roundabouts.

Study Citation: Bagley, D.L. "Evaluation of Roundabouts on High-Speed Roadways." North Carolina Department of Transportation. (January 2020).


CMFs Associated With This Study

Category: Intersection geometry

Countermeasure: Conversion of intersection into high-speed roundabout

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.59 41 4 Stars All All All All
0.21 79 3 Stars All K,A,B,C All All
0.38 62 3 Stars Other All All All
0.04 96 3 Stars Other K,A,B,C All All
0.62 38 3 Stars All All All All
0.57 43 3 Stars All All All All
0.17 83 3 Stars All K,A,B,C All All
0.21 79 3 Stars All K,A,B,C All All
0.15 85 3 Stars Other All All All
0.45 55 3 Stars Other All All All
0 100 3 Stars Other K,A,B,C All All
0.05 95 3 Stars Other K,A,B,C All All