Abstract
Keywords safety, cars, crashworthiness, aggressivity, logistic
Abstract
The Automobile Research Institute (INSIA) is carrying out a research on the influence of car age in accident and injury risk. These measures will be used to estimate the safety effects of car scrapping schemes. This paper presents a study of the contribution of the improvements in the crashworthiness of passenger cars to the reduction of injury risk of drivers involved in road crashes. This have been done through the development of models that allow the probability of injury to be a function of the year of registration of the car.
Data from the Spanish Road Accident Database have been used. This database provides information on accidents in which at least one person was injured. Thus, it is not possible to fully assess the role of improved crashworthiness in reducing the total number of injuries; only the changes in the proportion of injured drivers who are killed or seriously injured (measure known as injury severity) can be studied.
Three samples have been considered in order to adjust the models of injury severity: (i) drivers involved in any type of road accident, (ii) drivers involved in single car accidents, and (iii) drivers involved in two-car collisions. Single car accidents and two-car collisions account for about 90% of all car occupant fatalities, and, thus, the analysis of these two specific cases allows to explain the evolution of the injury severity of drivers involved in all crashes. Besides, analysis of two car collisions allows to analyze not only crashworthiness of cars of a given year of registration, but also aggressivity of these cars towards other vehicles.
The methodology of this work is based on the use of logistic regressions. As well as the year of registration, factors related to the driver and the environment have been included in the analysis.
No significant reduction of injury severity for more modern cars was found in single car accidents. In two car collisions, the results of logistic regressions show an important improvement of crashworthiness, but it also has been detected an increase of aggressivity towards other vehicles. The lack of information regarding variables such as vehicle mass, pre-collision velocities and delta-v prevents a deeper and more precise approach.