Using Simulation to Assess Conflicts Between Bicyclists and Right-Turning Vehicles

2019PDFTech ReportChristofa, EleniKnodler Jr., Michael A.Deliali, AikateriniUniversity of Massachusetts at Amherst. Department of Civil and Environmental EngineeringSafety Research Using Simulation (SAFER-SIM) University Transportation CenterSafety Research Using Simulation (SAFER-SIM) University Transportation CenterUnited StatesBehaviorBicycle lanesCyclistsDriversDriving simulatorsEye movementsIntersection elementsOperating speedRight turnsTraffic safetyTraffic conflictsTurning trafficVehicle mix69A3551747131Protected bike lanes, or cycle tracks, are increasing in popularity across the nation. However, despite the documented benefits of protected bike lanes, including safer cycling and increased ridership among differing populations of bicyclists, there remain ongoing concerns about potential conflicts between bicycles and vehicles when they merge back together at an intersection. The fear is that following a period of separation, drivers are less likely to anticipate and scan for the presence of bicycles. This research examines how transitions from fully separated to mixed-traffic environments and vice versa affect driver behavior. The goal is to assess whether certain segment-intersection treatment combinations can alert drivers of the presence of bicyclists and thus encourage them to scan for bicyclists prior to a right turn, reducing potential right-hook conflicts. Driving simulation is utilized in this study, and driver performance for right-turning vehicles is recorded under the presence of various bicycle infrastructure treatments along segments and at intersections. The experimental design includes two types of bike lanes and two intersection configurations, namely conventional and protected bike lanes and intersections with through bike lanes and protected intersections. Results show that the presence of the bicyclist as well as the presence of protected bike lanes reduce average speed on the segment. Additionally, the presence of the bicyclist significantly reduces the intersection speed when non-protected intersection design has been implemented. The presence of the bicyclist was also found to significantly affect participants\u2019 glancing behavior at the intersection approach, triggering more of them to place a right glance regardless of the intersection configuration. In addition, participants were found to be less likely to glance for the bicyclist when riding on a segment with protected bike lanes compared to scenarios with conventional bike lanes. This research can be used to guide decisions on bicycle infrastructure implementation for safer multimodal operations.95