Right-Hook Crash Scenario: Effects of Environmental Factors on Driver's Visual Attention and Crash Risk

A right-hook (RH) crash is a common type of bicycle-motor vehicle crash that occurs between a right-turning vehicle and through-moving bicycle at an intersection in right-hand driving countries. Despite the frequency and severity of this crash type, no significant driver-performance based evidence of the causes of RH crashes at signalized intersections was found in the literature. This study examined the driver's visual attention in a right-turning scenario at signalized intersections with bicycle lanes but no exclusive right-turning lanes while interacting with a bicyclist to develop an understanding of RH crash causality. Fifty-one participants in 21 simulated road scenarios performed a right-turning maneuver at a signalized intersection while conflicting with traffic, pedestrians, and bicyclists. Overall, a total of 820 (41 × 20) observable right-turn maneuvers with visual attention data were analyzed. The results show that in the presence of conflicting oncoming left-turning vehicular traffic, drivers spent less visual attention on the approaching bicyclist, thus, making them less likely to be detected by the driver. The presence of oncoming left-turning traffic and the bicyclist's speed and relative position, and conflicting pedestrians were found likely to increase the risk of RH crashes. The results of the current study will help identify effective crash mitigation strategies that may include improving the vehicle-human interface or the implementation of design treatments in the road environment to improve driver and bicyclist performance.