Negotiation-Based Conflict Exposure Methodology in Roundabout Crash Pattern Analysis

1 This paper provides a comprehensive analysis of roundabout crash patterns. First, an improved 2 method was used to calculate crash type percentages for Wisconsin roundabouts. Second, the 3 crash type patterns were compared between roundabout types and between at-fault driver 4 residency types. It was found that the entering-circulating crash was the severest at single-lane 5 roundabouts while the sideswipe crash had a higher percentage at multilane roundabouts. Local 6 drivers were more involved in rear-end crashes while drivers from outside of the city committed 7 more sideswipe crashes. Third, to provide an insight into crash patterns based on driving 8 behavior, 12 types of inappropriate negotiations were defined and quantified through video data. 9 The conflict exposure rates were then defined and measured to interpret the crash patterns. The 10 results from the conflict exposure analysis showed why a high percentage of sideswipe crashes 11 appeared at multilane roundabouts. 12