Abstract
Research and/or Engineering Questions/Objective
This paper describes the main findings of a coordinated study performed by INSIA-UPM aimed to assess the potential influence of several autonomous emergency braking systems (AEB) in vehicle-pedestrian collisions through reconstruction of real-world accidents occurred in the city of Madrid (Spain).
Methodology
A total number of 50 vehicle-pedestrian collisions have been in-depth investigated following a common methodology, including on the spot data collection, analysis and reconstruction to estimate the collision speed and the pedestrian kinematics. Every single case has been virtual simulated twice using PC-Crash® software: the first is a reconstruction of the real accident and the second is a simulation in which the operation of AEB systems is emulated. The AEB systems emulated in this paper through computer simulations are based on: the the Volvo’s City Safety system; the Subaru Eyesight system; the Continental ContiGuard system; the Daimler Chrysler PRE-SAFE system and the Toyota A-PCS system. The benefit is assessed in terms of both collision speed and Injury Severity Probability (ISP) by comparing the reduction of their values from the real conditions to the virtual simulations. The pedestrian ISP was estimated, depending on the collision speed and the head impact point, using a specific application to calculate its value based on the results of head form impact laboratory tests.
Results
The findings show that in several cases the collision could be avoided by implementing the AEB systems; and it would reduce their consequences in terms of the estimated ISP. It was also found that in few cases a low reduction of the collision speed would increase the head injury severity.
Limitations of this study
Further research should include injury information and/or estimation (HIC). Other limitations are the sample size (only one city and frontal collisions) and no unhurt accidents have been included. The injury severity assessment within this study only considers head impacts to the front surface of the vehicle, injuries provoked by subsequent impacts were not taken into account. Hence it can be an interesting subject for further research.
What does the paper offer that is new in the field including in comparison to other work by the authors?
This is new because: it is a prospective assessment of automatic brake system; it is based on accurate reconstructions, highly detailed parameters; the behavior of the system is simulated according to design parameters.
Conclusions
Multi-disciplinary approaches such as this study make the identification of critical parameters easier and simplify the development of practical solutions by quantifying their potential impact on future actions to improve pedestrian safety. The autonomous emergency braking pedestrian systems have a potential benefit in real conditions. It also has limitations so we cannot rely just on it. It has to act together with other passive features and the driver has to keep aware.
Key Words : Pedestrian safety; autonomous emergency braking system (AEB); on the spot accident investigation; injury severity probability; accident reconstruction