CHARACTERISTICS ON FRACTURES OF TIBIA AND FIBULA IN CAR IMPACTS TO PEDESTRIANS AND BICYCLISTS – INFLUENCES OF CAR BUMPER HEIGHT AND SHAPE Otte, D.*; Haasper, C. **

This study deals with the analysis of lower leg fractures in pedestrians and bicyclists after collisions with passenger cars and examines to what extent the shape and location of the factures in the lower leg changed, following alterations in the shape of bumpers. It can be assumed that that the bumpers changed in shape and effective impact height, not least due to the realization of the developments of vehicle safety tests as in the context of the European Union Directive 2003/102/EC on pedestrian protection. In addition, consumer protection tests, EuroNCAP, accomplished a change of the injury situation. All of these are mainly focused on pedestrian protection measurements but adopt the bicyclists also in their goal. For the study, traffic accidents from GIDAS (German in-DepthAccident Study) were selected, which had been documented in the years 1995 to 2004 by scientific teams in Hannover and Dresden (Germany) and for which there is detailed information regarding injury patterns and collision speeds. The accident documentations can be regarded as representative and constitute a random sample with statistic weighing of the data. Altogether 143 cases of lower leg fractures (Tibia/ Fibula) with x-rays of pedestrians and 79 cases of bicyclists were differentiated according to new and old vehicles (year of manufacture before/after 1995). The bumper shapes were divided into classical types (protruding pronouncedly/ protruding integrated /integrated rounded). Besides the injuries to the lower leg, those to thighs and feet were also regarded, and the injury conditions involving the head and trunk were included in the kinematic analytics. PEDESTRIAN AND BICYCLIST SAFETY has significantly improved over the past 30 years. While in 1975 in a country like the Federal Republic of Germany (StBA, 2006), n=3973 fatal pedestrians and n=1387 fatal bicyclists and additionally n=60033 casualties amongst pedestrians as well as n=45317 casualties amongst bicyclists were recorded, the number of n=686 fatalities and n=33803 casualties on pedestrians and n=475 fatalities and n=73162 casualties on bicyclists in 51 ANNUAL PROCEEDINGS ASSOCIATION FOR THE ADVANCEMENT OF AUTOMOTIVE MEDICINE October 15 – October 17, 2007 the year 2005 seems to good in comparison. Nevertheless it should not be overlooked that in today's Europe of 27 different countries there are still far more than approximately 8,000 pedestrians and cyclists, also categorized as Vulnerable Road Users (VRU), killed and a further 300,000 are injured each year in road accidents in Europe. This requires manifold efforts of scientific research, which can no longer be limited exclusively to passive security like injury reduction, but must also aim at measures of active security for the avoidance of accidents. This study is concerned with the question to what extent changes to the front design of vehicles particularly the bumper caused by test activities and by the test conditions for new vehicles, change the resulting injury pattern on the lower legs of pedestrians and bicyclists. To this end, fractures of the lower legs of pedestrians and bicyclists have been examined after collisions with passenger cars, in order to determine impact height of the bumpers and changes to the fractures of the lower legs, regarding characteristic and location. It can be assumed that that the bumpers changed in shape and effective impact height, not least due to the realization of the developments of vehicle safety tests as specified in the context of the European Union Directive 2003/102/EC (2003). In addition, consumer protection tests, EuroNCAP, accomplished a change of the injury situation. All of these are mainly focused on pedestrian protection measurements but adopt the bicyclists also in their goal. What differences are there between pedestrians and bicyclists concerning their injury pattern? The test according to the European Union directive as well as that according to EuroNCAP stipulate that with the so-called "Lower leg form impactor" at an impact speed of 40 km/h no accelerations of more than 150 to 200g may occur and that the dynamic lateral shift amounts to less than 6 mm and that the maximum knee bending angle is not to exceed 21 degrees. It is to be expected that this will result in larger force transfer areas of the bumper bodies and to a higher location of the force transfer area in the lower leg especially of the pedestrians compared to the situation of a pedestrian the seat position of a bicyclist is approximately 10 cm higher and the inclined position of the leg depends from the pedal’s downward or upward position. It is the goal of this study to examine the traffic accidents documented in collections of GIDAS at accident sites in Hannover and Dresden for accidents involving pedestrians and bicyclists with passenger cars and for this purpose to analyse the characteristics of the fractures and measure the heights of fractures of the lower legs from x-rays and to assign them to the geometrical shapes and heights of the bumpers. In order to recognize possible shifts of the injury spectrum and the injury mechanisms responsible for the occurrence of the fracture, all accompanying fractures occurring along the entire leg have to be regarded. In order to be able to recognize the influence of newer vehicle models, the vehicles involved should be differentiated according to the