Modeling pedestrian safety at roundabouts

This study proposes a method for using a human participant in a field experiment to model pedestrian safety at roundabouts in the United States. Studies show that roundabouts are safer for vehicles, but are inconclusive as to whether pedestrians are at greater risk at roundabouts than at signalized intersections. Recent simulations, including virtual reality, can model pedestrian vehicle interaction, but the proposed technique could use real-world data to calibrate these models. Eight hours of video was made to gather data at a signalized intersection and a roundabout. A physical simulation was used to assess the pedestrian’s cross/don’t cross decision. Standard walking pace was simulated at 3.5 feet per second and a disabled pedestrian at half that pace. This study focused on factors such as signalization, approach streams, exit vs. entrance lanes, pace and direction to provide a realistic picture of the cross vs. don’t cross decision. Data showed that slow pedestrians had a significantly higher rate of don’t cross decisions at the roundabout. Roundabouts are thought to be safer for pedestrians than signalized intersections due to a lower number of conflict points, but the confusing multiple streams of roundabout traffic converging on exit lanes and the frames of approaching traffic at roundabout entrances may mean that another concept may be needed to fully capture pedestrian risks. The data on ‘relevant traffic’ showed that pedestrians had to be attentive to almost six times as many approach streams of traffic in the roundabout as in the signalized intersection. The value of this study is four-fold: 1) Future studies could revisit the conflict point at the core of Traffic Conflict Analysis and consider conflict streams as well; 2) Future studies could consider the cross/don’t cross decision as an important data point with which to evaluate the safety of roundabout crossings; 3) Slow pedestrians fared worse in their ability to cross at the roundabout than at the signalized intersection; 4) The human participant in a field experiment method can be a valuable source of data for calibrating pedestrian safety simulation systems.