Search Results

Pedestrians and bicyclists account for a significant share of deaths and serious injuries in the road transport system. The protection of pedestrians in car-to-pedestrian crashes has therefore been addressed by friendlier car fronts and since 1997, the European New Car Assessment Program (Euro NCAP) has assessed the level of protection for most car models available in Europe. In the current study, Euro NCAP pedestrian scoring was compared with real-life injury outcomes in car-to-pedestrian and car-to-bicyclist crashes occurring in Sweden. Approximately 1200 injured pedestrians and 2000 injured bicyclists were included in the study. Groups of cars with low, medium and high pedestrian scores were compared with respect to pedestrian injury severity on the Maximum Abbreviated Injury Scale (MAIS)-level and risk of permanent medical impairment (RPMI). Significant injury reductions to both pedestrians and bicyclists were found between low and high performing cars.

Infrastructure systems such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) communication can theoretically prevent nearly all accidents by gathering the speed, locations, and travel directions of traffic participants, and intervening to control vehicle motion as required to help prevent collisions. However, during the phase-in of the communication systems, there will be many vehicles and many roads that do not have the communication systems in place, and therefore the system will not be effective in those cases. This lack of availability is likely the main disadvantage. On-board sensing (autonomous) systems such as cameras and radar sensors may not detect all potential hazards (e.g. due to weather, or hidden hazards), but they are effective in many situations and can help prevent crashes without depending on communication with infrastructure or other vehicles.

The problem of incompatibility between different car types has become an important issue in the society. In two- car crashes, the aggressivity to the other vehicles is a factor often mentioned. In this study aggressivity is defined as the influence on injury outcome in the other vehicle due to differences in car structure and mass of the studied vehicle. The study was based on police-reported two-car collisions in Sweden. The influence of car mass and structure on driver relative injury risk was for some vehicle categories analyzed with a new developed technique where the influence of mass and structure was separated. SUVs were found to have 32% higher mass factor and 23% higher structural aggressivity factor than the average value, resulting in a 62% higher total aggressivity factor than the average.

The European crash test program, Euro NCAP, has since its launch presented results of some 80 individual car models. The improvements in the general level of protection have been substantial. While the intention of the test program is to stimulate the use of best practice, and not to predict real-life outcome, it is nevertheless important to validate the positive development, and to pinpoint potential areas not included in the laboratory safety ratings. In this study, Euro NCAP rating results were compared with a comprehensive car model safety rating method based on real-life crashes, developed by Folksam. In addition, correlation with relative injury risks was also studied. In the Folksam method, the ratings are based on the risk of fatalities and long-term consequences due to injury. The car models were grouped together according to the Euro NCAP star ratings.

This paper presented a part of results from an ongoing project for pedestrian protection, which is carried out at Chalmers University of Technology in Sweden. A validated pedestrian mathematical model was used in this study to simulate vehicle-pedestrian impacts. A large number of simulations have been carried out with various parameters. The injury-related parameters concerning head, chest, pelvis and lower extremities were calculated to evaluate the effect of impact speed and vehicle front structure on the risk of pedestrian injuries. The effect of following vehicle parameters was studied: stiffness of bumper, hood edge, hood top, windscreen frame, and shape of vehicle front structures. A parameter study was conducted by modelling vehicle-pedestrian impacts with various sizes of cars, mini vans, and light trucks. This choice represents the trends of new vehicle fleet and their frequency of involvement in real world accidents.

The safety situation in Sweden has improved the last decade but the positive trend has levelled out the last few years. The parliament has taken interest in the problem and has formulated the “Vision Zero” as a new strategy. The Vision Zero claims that it is not acceptable to have fatalities and injuries leading to long-term problem in the road transport system. The government has further focussed the work by a special 11-point program for traffic safety and an investigation how to establish legislation giving all system designers larger responsibility for the safety level in the road transport system. New better knowledge is needed to support the new strategy. Changing the focus from accidents to preventing severe injuries will help to solve the problem. More co-operations between the various traffic safety disciplines are urged for in the design of a crashworthy road transport system, where vehicles, infrastructure, speed and human failures are handled simultaneously.