Abstract
In 2010, the total traffic deaths in Japan were 4,863. The 2010 traffic fatality numbers show that the pedestrian fatalities are the largest portion of the traffic casualties in Japan (1,714, 35%). Vehicle travel velocity at pedestrian contact is considered to be an important parameter that affects the crash outcome. To reduce vehicle/pedestrian impact velocity, a collision damage mitigation braking system (CDMBS) using sensor for pedestrian detection could be an effective countermeasure. Currently in Japan, cars equipped with the CDMBS have also vision sensors such as a stereo camera for pedestrian detection. However, the technical performance of production cars as to their capability to properly detect pedestrians has not yet been established.
The objective of the present study is to determine the safety performance of production cars equipped with the CDMBS for pedestrian protection. The authors performed a series of impact tests simulating a traffic crash involving a car and a pedestrian using a foam mannequin representing a 7 year old child. Firstly, the authors investigated effect of car travel velocities on pedestrian detection. Test car travel velocities were selected as 20, 30, 40, 50 and 60 km/h, respectively for various test runs based on the velocity distribution in real-world pedestrian crashes. The authors found that the tested production car equipped with the CDMBS based vision sensor could be effective to reduce the impact velocities for car travel velocities in the range of 20 km/h and 60 km/h. In other words, the system could have the potential to reduce pedestrian casualties from car-to-pedestrian contacts. Secondly, the authors investigated a detectable zone with respect to a pedestrian’s position in relation to the car. It was showed that the system could detect a pedestrian mannequin that was standing in a zone inside the car front width. However, the car velocity did not reduce at the offset-long position, which was the case that the pedestrian mannequin was standing outside the car front width. Thus, the detectable zone for the system was limited for the production car tested to be inside the car front width. Thirdly, the authors investigated effect of arms on pedestrian detection. It was clarified the arms had no effect on detecting the pedestrian in the tests using the pedestrian mannequin with arms and without arms.
Keywords: Pedestrian Safety, Collision Damage Mitigation Braking System, CDMBS, Pedestrian Detection