The safety implications of adopting roundabouts in place of conventional signalized intersections have not been adequately assessed. A microscopic simulation model was used to compare the pattern of traffic conflicts at roundabouts with conflicts for signalized intersections. Three indicators of safety performance were defined: (a) time to collision (TTC), (b) deceleration rate to avoid the crash (DRAC), and (c) crash potential index (CPI). For each indicator, traffic conflict profiles were obtained in terms of number of vehicles in conflict and number of conflicts per vehicle for selected directional maneuvers. The exposure time to conflict for each maneuver and vehicle was also determined. Twelve combinations of geometric and traffic attributes (traffic scenarios) were simulated over a 15-min period. The results suggested that roundabouts yield reduced exposure times to rear-end conflicts compared with signalized intersections. On average, signalized intersections also reflected increased number of vehicles in conflict and percentage of vehicles in conflict compared with roundabouts. This relationship was found to be independent of input volumes and pavement surface condition and applied consistently to all safety indicator measures (TTC, DRAC, and CPI).


    Access

    Download

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Comparing Safety at Signalized Intersections and Roundabouts Using Simulated Rear-End Conflicts


    Additional title:

    Transportation Research Record: Journal of the Transportation Research Board


    Contributors:


    Publication date :

    2008-01-01




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English






    Simplified Method for Comparing Emissions in Roundabouts and at Signalized Intersections

    Salamati, Katy / Rouphail, Nagui M. / Frey, H. Christopher et al. | Transportation Research Record | 2019


    Comparing Traffic Noise Levels between Signalized Intersections and Roundabouts in an Urban Environment

    Abdur-Rouf, Khadija / Shaaban, Khaled | Transportation Research Record | 2022