Evasive action characteristics of motorcycle riders towards occluded-surprise and expected pedestrians: A pedestrian mock-up study

Evasive action performance of motorcycle riders plays a vital role in the prevention of road crashes. In possible conflicting scenarios, motorcycle riders need to respond quickly and perform evasive actions successfully to prevent collisions with other vulnerable road users such as crossing pedestrians. To study the motorcycle rider behavior in conflicts with occluded and visible pedestrians, we designed four mock-up pedestrian scenarios, which includes, two surprise scenarios, one stationary scenario, and one expected scenario. Riders’ responses to the conflicts were measured using instrumented vehicle’s trajectory. Most riders preferred deceleration over swerving at the beginning of the interaction, followed by swerving at manageable speeds. Further, the analysis of riders’ deceleration rates revealed that a linear relationship existed between the deceleration rates and time to collisions (TTC). The study also analyzed the riders’ responses using repeated-measures analysis of variance (RM-ANOVA) to check for the effect of scenario type on deceleration rates. Results indicated that scenario type significantly affected the mean deceleration rates. Further, RM-ANOVA analysis carried out on the jerk behavior of motorcycle riders indicated that there was a significant effect of scenario type on the jerk behavior. Motorcycle riders’ jerks varied linearly with TTC and motorcyclists employ relatively higher decelerations and jerks when faced with pedestrians emerging suddenly from occluded locations such as from the blind spots formed due to parked vehicles. This study helps in understanding motorcycle rider behavior in critical situations and shows the need for assistive evasive systems for motorcycle riders to mitigate collisions with other vulnerable road users.     

Evaluation of motorized two-wheeler rider responses towards jaywalking pedestrians through mockup control studies for urban streets

This study aims to model the motorized two-wheeler (MTW) riders’ evasive-action behavior towards jaywalking pedestrians using a mockup study. The brake reaction times (BRTs), approach speeds, decelerations, headings, and yaw rates were analyzed for two surprise scenarios (scenarios 1 and 3), one stationary scenario (scenario-2), and one expected scenario (scenario-4). In total, 50 riders participated in the mockup study. The results revealed that the 90th percentile BRT for the expected and surprise scenarios were 3.6 and 1.6 s, respectively. Further, repeated-measures ANOVA was performed followed by mixed effect modeling to ascertain the effect of conflict severity (two groups: group-1 with Time to Collision (TTC) < 1.5 s and group-2 with TTC > 1.5 s) and scenario type (three groups: scenarios 1, 3 and 4) on BRT. The results indicated that the main effects were significant while the interaction effect was not significant. The positive and significant coefficient (0.32) of TTC group-2 indicated higher BRTs than TTC group-1. Considering scenario-1 as the base scenario, the coefficient of scenario 3 (-0.02) indicated that scenario-1 and scenario-3 had a similar effect on BRT, while the coefficient of scenario-4 (1.47) indicated higher BRTs compared to scenario-1. The analysis of evasive action behavior revealed that 32% of riders performed hard braking in surprise scenarios. Further, yaw rate values at the crossing point indicated a loss of control of MTW in 90% of surprise events. The observations from this study provide a basis for developing countermeasures to improve pedestrian and MTW rider safety.