title: Road safety effects of roundabouts: A meta-analysis.
abstract: This paper presents a meta-analysis of the road safety effects of converting junctions to roundabouts. 44 studies containing a total of 154 estimates of effect were included. Based on a meta-regression analysis, converting junctions to roundabouts is associated with a reduction of fatal accidents of about 65% and a reduction of injury accidents of about 40%. The mean effect on property-damage-only accidents is ambiguous. Summary estimates of effect are robust for fatal and injury accidents, but vary depending on the model of meta-analysis and the treatment of outlying data points for property-damage-only accidents. A trim-and-fill analysis suggests a weak tendency for publication bias, with modest influence on summary estimates of effect. It is concluded that roundabouts are very effective in reducing traffic fatalities.
authors.affiliation: Institute of Transport Economics, Gaustadalleen 21, 0349 Oslo, Norway. Electronic address: re@toi.no.
authors.forename: Rune
authors.initials: R
authors.lastname: Elvik
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D004779:Environment Design / Q000592:standards*; D005060:Europe; D006801:Humans; D008962:Models, Theoretical; D012044:Regression Analysis; D012449:Safety / Q000592:standards*
keywords: Meta-analysis; Meta-regression; Roundabouts; Safety effects