Features of Car–cyclist Contact Situations in Near-miss Incidents Compared with Real-world Accidents in Japan

The use of active safety devices that can detect cyclists is considered an effective countermeasure for the reduction of the severity of injuries and number of deaths of cyclists. The detailed features of car–cyclist contact scenarios need to be clarified to develop such safety devices. Because there is limited information on real-world accidents, the present study investigates near-miss scenarios captured by drive recorders installed in passenger cars. The first purpose of the present study is to ascertain the utility of using near-miss scenarios in clarifying the features of situations of contact between cars and cyclists. The similarities of data of near-miss incidents including video captured by drive recorders and national data of real-world fatal cyclist accidents in Japan are investigated. We used 229 videos of near-miss car–cyclist incidents collected by the Society of Automotive Engineers of Japan (J-SAE) from 2005 to 2009. In scenarios where the car travels straight ahead, 70–84% of cyclists on straight roads or at intersections crossed the road in front of the forward-moving cars both in accidents and near-miss incidents. There are thus similarities between accidents and near-miss incidents and it is possible to estimate the situations of cyclists’ accidents from near-miss incident data including video that captures cyclist behavior. The second purpose of the study is to calculate the time to collision (TTC) from the near-miss incident data. The study analyzed data for 166 near-miss car–cyclist incidents in which cyclists crossed the road in front of forward-moving cars on straight roads or at intersections. We calculated the TTC from the velocity of the car with an installed drive recorder and the distance between the car and the cyclist at the moment the cyclist appeared in the video captured by the drive recorder. The average TTC was 2.1 s (Standard Deviation (SD) of 1.6 s). In terms of the manner in which cyclists emerged in front of cars, the average TTC was the shortest (1.9 s) when cyclists emerged from behind a building or moving vehicle in the opposite lane. We propose that the specifications of a safety device developed for cyclist detection and automatic braking should reflect detailed information that includes the TTC obtained for near-miss situations.