Automated Vehicles Symposium 2019

Pedestrian and Bicycle Accommodations at Continuous Flow Intersections (Room Palms Ballroom - Booth 100)

16 Jul 19
5:30 PM - 7:00 PM

Although Continuous Flow Intersections (CFI) have a great potential for improving vehicular capacity and operations, the unique challenges pedestrian and bicyclists face at these facilities are often not fully considered in their design. In this study, pedestrian and bicycle accommodations on a CFI design are tested in a microsimulation environment. Three types of crossing geometries, namely, Traditional, Offset, and Midblock crossing are proposed to be tested using the VISSIM microsimulation tool. Past studies and existing CFI installations are explored to identify key features that are critical to the quality of service of non-motorized users. Based on these reviews,  a number of alternative treatment scenarios have been generated by varying the number of displaced left-turn legs, bicycle path types, and the control type for right-turn movements. These features generally dictate the intersection footprint, delay, and the number of stops for non-motorized users. In all, a total of 24 alternative treatment scenarios were modeled in VISSIM. The performance of these crossing alternatives is compared based on the estimated stopped delay and number of stops the pedestrian-bicycle users experienced. It was found that the Offset crossing generated the lowest stopped delay across all alternative scenarios with an overall average of 61, 67, and 50 seconds per user for pedestrians, bicycles on the shared path, and bicycles on an exclusive path, respectively. The Midblock crossing yielded the highest stopped delay with an overall average of 89, 82, and 62 seconds per user for pedestrians, bicycles on the shared path, and bicycles on the exclusive path, respectively. By contrast, the Traditional crossing generated the lowest average number of stops for pedestrians (1.3 stops per user) and bicycles on the shared path (1.2 stops per user), while the Offset crossing generated the highest (1.6 and 1.7 stops per user for pedestrians and bicycles on the shared path, respectively). For bicycles on the exclusive path, the trend in the number of stops varied for partial and full CFI models. On a route level, the observed trends may deviate significantly based on the type of routes contemplated. Future research includes comparing the performance of pedestrian-bicycle accommodations at CFIs with those at a traditional intersection geometry that provides equivalent vehicular quality of service to the CFI.