Study Details
Study Title: Safe roundabouts for cyclists
Authors: Jensen, S. U.
Publication Date: 2017
Abstract: May roundabouts be safer for cyclists than intersections? How are safe roundabouts designed? This paper tries to answer these questions on the basis of a before-after safety study of conversions of intersections to 255 single-lane roundabouts in Denmark. The before-after study accounts for long-term accident and injury trends and regression-to-the-mean effects. In order to relate safety effects for cyclists of various roundabout design features it is crucial to split the converted sites by speed limit, because safety effects for both cyclists and other road users of converting intersections to roundabouts depend heavily on speed limits on roads entering the converted sites. If speed limits are 70 km/h or higher then converting intersections to roundabouts have resulted in bicycle safety improvements in Denmark. Results show that diameter and height of central islands and type of bicycle facilities at single-lane roundabouts have considerable impacts on cyclists’ safety. Central island diameters of 20–40 m are safer for cyclists than smaller or larger roundabouts. A central island, which middle is elevated 2 m or more above the circulating lane, is safer for cyclists than single-lane roundabouts with lower central islands. Single-lane roundabouts with separate cycle paths, where cyclists must yield to motorists entering or exiting the roundabout, are safer than roundabouts with cycle lanes. Single-lane roundabouts are safer for cyclists than intersections regardless of speed limits when these roundabouts have high central islands and/or separate cycle paths.
Study Citation: Jensen, S.U. "Safe roundabouts for cyclists". Accident Analysis and Prevention, Vol. 105, (2017) pp. 30-37.
Study Report: Download the Study Report Document
Comments: This review excluded CMFs with zero expected crashes and zero observed crashes as the Clearinghouse team did not feel that these were implementable findings.
CMFs Associated With This Study
Category: Intersection geometry
Countermeasure: Conversion of intersection into single-lane roundabout
CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
---|---|---|---|---|---|---|
0.48 | 52 | Other | All | Not specified | Rural |
0.54 | 46 | Other | All | Not specified | Rural |
0.51 | 49 | Other | All | Not specified | Rural |
2.67 | -167 | Vehicle/bicycle | All | Not specified | All |
3.39 | -239 | Vehicle/bicycle | All | Not specified | All |
2.89 | -189 | Vehicle/bicycle | All | Not specified | All |
0.53 | 47 | Vehicle/bicycle | All | Not specified | All |
0.5 | 50 | Vehicle/bicycle | All | Not specified | All |
2.33 | -133 | Vehicle/bicycle | All | Not specified | All |
0.73 | 27 | Other | All | Not specified | All |
0.84 | 16 | Other | All | Not specified | All |
0.78 | 22 | Other | All | Not specified | All |
0.39 | 61 | Other | All | Not specified | All |
0.39 | 61 | Other | All | Not specified | All |
0.67 | 33 | Other | All | Not specified | All |
2.62 | -162 | Vehicle/bicycle | All | Not specified | All |
1.2 | -20 | Vehicle/bicycle | All | Not specified | All |
1.53 | -53 | Vehicle/bicycle | All | Not specified | All |
1.11 | -11 | Vehicle/bicycle | All | Not specified | All |
1.11 | -11 | Vehicle/bicycle | All | Not specified | All |
1.48 | -48 | Vehicle/bicycle | All | Not specified | All |
0.92 | 8 | Other | All | Not specified | All |
0.44 | 56 | Other | All | Not specified | All |
0.57 | 43 | Other | All | Not specified | All |
1.44 | -44 | Other | All | Not specified | All |
1.44 | -44 | Other | All | Not specified | All |
0.72 | 28 | Other | All | Not specified | All |
0 | 100 | All | All | Not specified | Urban |
0 | 100 | Vehicle/bicycle | All | Not specified | Urban |
0 | 100 | Vehicle/bicycle | All | Not specified | Rural |
0 | 100 | Vehicle/bicycle | All | Not specified | All |
0 | 100 | Other | All | Not specified | All |
1.06 | -6 | All | All | Not specified | Urban |
0.85 | 15 | All | All | Not specified | Urban |
1.34 | -34 | All | All | Not specified | Urban |
0.78 | 22 | All | All | Not specified | Rural |
0.53 | 47 | All | All | Not specified | Rural |
0.81 | 19 | All | All | Not specified | Rural |
0.75 | 25 | All | All | Not specified | All |
0.68 | 32 | All | All | Not specified | Urban |
0.54 | 46 | All | All | Not specified | Rural |
0.41 | 59 | All | All | Not specified | Rural |
0.94 | 6 | All | All | Not specified | Rural |
0.52 | 48 | All | All | Not specified | All |
2.73 | -173 | Vehicle/bicycle | All | Not specified | Urban |
1.88 | -88 | Vehicle/bicycle | All | Not specified | Urban |
2.24 | -124 | Vehicle/bicycle | All | Not specified | Urban |
1.75 | -75 | Vehicle/bicycle | All | Not specified | Rural |
1.1 | -10 | Vehicle/bicycle | All | Not specified | Rural |
2.03 | -103 | Vehicle/bicycle | All | Not specified | All |
0.71 | 29 | Vehicle/bicycle | All | Not specified | Urban |
0.38 | 62 | Vehicle/bicycle | All | Not specified | Rural |
0.69 | 31 | Vehicle/bicycle | All | Not specified | Rural |
0.56 | 44 | Vehicle/bicycle | All | Not specified | All |
2.02 | -102 | Vehicle/bicycle | All | Not specified | Urban |
2.33 | -133 | Vehicle/bicycle | All | Not specified | Urban |
1.48 | -48 | Vehicle/bicycle | All | Not specified | Urban |
0.36 | 64 | Vehicle/bicycle | All | Not specified | Urban |
1.98 | -98 | Vehicle/bicycle | All | Not specified | Urban |
0.55 | 45 | Other | All | Not specified | Urban |
0.67 | 33 | Other | All | Not specified | Urban |
0.72 | 28 | Other | All | Not specified | Urban |
0.61 | 39 | Other | All | Not specified | Urban |
0.66 | 34 | Other | All | Not specified | Urban |
2.25 | -125 | Vehicle/bicycle | All | Not specified | Rural |
1.02 | -2 | Vehicle/bicycle | All | Not specified | Rural |
0.19 | 81 | Vehicle/bicycle | All | Not specified | Rural |
0.85 | 15 | Vehicle/bicycle | All | Not specified | Rural |
0.42 | 58 | Other | All | Not specified | Rural |
0.52 | 48 | Other | All | Not specified | Rural |