Road Safety Effects of Roundabouts in Flanders

In 1993, the Flemish government decided to invest heavily in the construction of roundabouts after statistics showed that twice as many accidents occurred at crossroads than on other road segments in Flanders (excluding highways). This study analyzes the effect on road safety of 95 roundabouts that were built in Flanders between 1994 and 1999. The data set includes all registered injury accidents that occurred between 1991 and 2000 at these locations as well as a comparison group of 119 road intersections without roundabouts. Findings show that the effect on the number and severity of road accidents adjusted for the trend and regression to the mean is significant, but varies considerably in accordance with the speed limits on the intersection. Roundabouts are most effective on intersections of a main road with a high speed limit and an adjacent road with a lower speed limit. The empirical analysis reveals a reduction of 34% for the total number of injury accidents, 30% for minor injury accidents, and 38% for serious injury accidents. This study also examines the impact of different post-implementation periods, using accident data of 1-, 3-, or 6-years after the construction of a roundabout, on the calculated effectiveness results. The effectiveness ratio appeared to change with the time span considered, with the effectiveness based on a 1-year post-implementation period showing an underestimation of accident reduction compared to a 3-year post-implementation period.

  • Availability:
  • Authors:
    • De Brabander, Bram
    • Nuyts, Erik
    • Vereeck, Lode
  • Publication Date: 2005


  • English

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Filing Info

  • Accession Number: 01003820
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Sep 3 2005 7:21PM