Abstract
The Laboratory of Accidentology, Biomechanics and studies of Human Behaviour PSA RENAULT (LAB, F) has been carrying out road accident studies for 40 years. It now owns a database including 15,000 inspected cars corresponding to 27,000 occupants with 70,000 detailed injuries. During the last forty years, this accidents data collection helped the French car manufacturers to provide a better protection to the car occupants involved in a collision. This paper aims at showing the interest of the follow-up of car fatalities causations coupled with long term studies in Biomechanics. For this purpose, it presents, as an example, the chronological evolution of the improvements in passive safety technologies from the 80’s on and their effectiveness assessed in terms of injuries reduction for the driver car in frontal impacts.
In 1980, 12,510 persons died on French roads. Among these fatalities, more than 5 out of 10 were car occupants. 47% out of these died in a frontal collision: all body regions were highly vulnerable, that means exposed to serious or fatal injuries. Road traffic fatalities dramatically decreased over the last three decades to reach the number of 4,275 fatalities in 2008. Accident analysis shows that the light structures of cars built in the 80’s could be made stiffer to provide driver car with a better protection in frontal impacts.
In the beginning of the nineties, the tendency was in the stiffening of the structure of cars. It corresponded also to the release of head airbags for the drivers (in France) which, coupled with the use of safety belts, allowed a significant decrease of the head injury risks and a substantial reduction of the risks for the other body regions except the thorax. In fact, vehicle stiffness maintained high decelerations applied by the seat belt to the thorax of the driver in frontal impacts. This thoracic injury risk was addressed by the car manufacturers in the last nineties by the introduction of load limiters.
In the years 2000, the increasing stiffness of the structures was implemented in conjunction with the implementation of improved airbags and new load limiters coupled with strong pretensioners. Passive safety was thought through a comprehensive concept. All body regions have directly benefited from these improvements: serious injury and fatal risks have considerably decreased. Thanks to the passive safety technologies (among others) serious injuries rate of the belted drivers in frontal impacts was divided by two over the last three decades.
Nowadays the LAB, rich in its knowledge of Accidentology and Biomechanics, carries on road safety studies considering an integrated approach.
Keywords: Passive safety, injury mechanism, Accident analysis, occupant protection