Abstract
Keywords:accidents, rural roads, automotive engineering, primary safety, secondary safety
In the last years there has been a decline in accident figures in Germany especially on rural roads. The number of fatalities on rural roads decreased from 4.767 in the year 2000 to about 3.230 in 2005. This positive development is mainly based on improved primary and secondary vehicle safety. However, the impact of automotive engineering on accidents of passenger cars on rural roads has not been quantified yet. For that purpose we examined by means of the national accident statistics in how far modern safety systems are responsible for the reduction of accidents and accident severity. First suitable safety systems were selected like brake assist, improved lighting or airbags which could have had a positive influence on certain accident configurations. In addition, the development of the equipment rates of the systems were determined. In a second step we selected subsets of all accidents on which the safety systems from a technical point of view should definitely have an influence. Accidents which could serve as control group were selected as well. To assess the effect of vehicle-related safety measures on the accident development the vehicle fleet was split for each year considered in this study into younger cars (1 or 2 years old) and older cars (5 to 14 years old) since the majority of the safety systems considered is fitted into newer vehicles. At the same time side effects depending on the age of the vehicle could be excluded. We thus examined if accident figures for younger vehicles which should be equipped with modern safety features were lower or were decreasing faster in the selected accident situations in comparison with both the control group and older vehicles. In detail the following assumptions were investigated: Vehicle stability control should have a positive influence on loss of control accidents. Brake assisting systems and anti-lock braking systems should mitigate rear-end accidents or accidents in which obstacles on the road were hit. Gas discharge lighting should have a positive effect on accidents during nighttime including pedestrians or obstacles on the road. Measures of secondary vehicle safety like airbags or improved vehicle structures taken due to consumer protection crash testing or new regulations with regard to frontal and side impact should have a mitigating effect especially in accidents with oncoming traffic. As a result of the study it could be verified by the figures of the German national accident statistics that there are essential effects of some primary vehicle safety systems on the number of accidents on rural roads. For secondary vehicle safety we could show significant reductions in accident severity. However, the study also demonstrated in which cases other means than national accident statistics are needed to prove safety gains due to automotive engineering.