Abteilung Fahrzeugtechnik
Refine
Document Type
- Conference Proceeding (13)
- Book (2)
Keywords
- Analyse (math) (15) (remove)
Institute
Many big cities in Europe and elsewhere in the world have problems managing the traffic especially during rush hours. The improvement of the parking problematic and environmental protection as well are important aspects for the future traffic design of urban areas. To improve the traffic situation the development of new traffic concepts and alternative vehicles are required. The BMW company has developed a new type of two-wheel vehicle. This two-wheeler constitutes a totally new concept. BMW implemented a lot of safety features, such as a structure made up of rollover bars and a crush element instead of a front protecting plate. Furthermore the driver can secure himself with two safety belts. The paper contains a description of the novel two-wheel vehicle concept designed so far. BMW's concept and the safety features are also explained. The Federal Highway Research Institute (BASt) was given the task of assessing the concept as a whole with regard to the active and passive safety and the exemption of the obligation to wear a helmet. The expertise concluded that the BMW two-wheeler concept has a very high safety standard. Some extracts of the expertise, in particular the investigations concerning the exemption of the obligation to wear a helmet are presented. Common legal requirements for the vehicle registration of vehicle concepts similar to the BMW two-wheeler in Germany have been formulated.
Safety of light goods vehicles - findings from the German joint project of BASt, DEKRA, UDV and VDA
(2011)
Light goods vehicles (LGVs) are an important part of the vehicle fleet, providing a vital component in the European transportation system. On the other hand, LGVs are in the focus of public discussion regarding road safety. In order to analyse the accident situation of LGVs in an objective manner, Federal Highway Research Institute (BASt), VDA, DEKRA and German Insurers Accident Research (UDV) launched a joint project. The aim of this project, which will be finished by mid of 2011, is to identify reasonable measures which will further improve the safety of LGVs. For the first time, these partners jointly together conducted a research project and put together their know-how in accident research. Analyses are based on real-life accident data from the GIDAS database, the Accident Database of UDV (UDB), the DEKRA database and national statistics. The findings deliver answers to questions within the arena of future legislative actions and consumer protection activities. The analyses of databases cover areas of primary and secondary safety of LGVs with a special focus on advanced driver assistance systems (ADAS), driver behaviour as well as partner and occupant protection. Key figures from national statistics are used to highlight hotspots of accidents of LGVs in Germany. Finally, the proposed countermeasures are assessed regarding their potential effectiveness. Amongst others, the results show that the accident situation of LGVs is very similar to that of passenger cars. Noteworthy variations could be found in collisions with pedestrians, at reversing and regarding accident causes. Occupant safety of LGVs is on a higher level compared to cars. Results indicate that seatbelt use is on a significantly lower level compared to cars. This leads to higher-than-average injury risk for unbelted LGV occupants. When it comes to partner protection, there are problems with compatibility at LGVs. For car occupants there is a very high injury risk when colliding with a LGV. It indicates that higher passive safety test standards for LGVs would be counterproductive if they further increase stiffness of LGVs. The analysis of LGV-pedestrian accidents shows that pedestrian kinematic differs significantly from car-pedestrian accidents. At this point, existing pedestrian related test standards developed for cars cannot be adopted to LGVs. When it comes to active safety, ESC proved its effectiveness once again. Beyond that, rear view cameras, advanced emergency braking systems and lane departure warning systems show a safety potential, too. In addition to any technical countermeasures previously discussed, the importance of the driver behavior and attitude regarding the accident risk was investigated. In order to develop successful actions it is important to understand the main target population. In the case of LGV especially the crafts business and smaller companies are the major contributors the safety issue.
Proposal for a test procedure of assistance systems regarding preventive pedestrian protection
(2011)
This paper is showing a proposal for a test procedure regarding preventive pedestrian protection based on accident analysis. Over the past years pedestrian protection has become an increasing importance also during the development phase of new vehicles. After a phase of focusing on secondary safety, there are current activities to detect a possible collision by assistance systems. Such systems have the task to inform the driver and/or automatically activate the brakes. How practical is such a system? In which kind of traffic situations will it work? How is it possible to check the effectiveness of such a system? To test the effectiveness, currently there are no generally approved identifiable procedures. It is reasonable that such a test should be based on real accidents. The test procedure should be designed to test all systems, independent of the system- working principle. The vFSS group (advanced Forward-looking Safety Systems) was founded to develop a proposal for a technology independent test procedure, which reflects the real accident situation. This contribution is showing the results of vFSS. The developed test procedure focuses on accidents between passenger cars and pedestrians. The results are based on analysis results of in-depth databases of GIDAS, German insurers and DEKRA and added by analysis of national and international statistics. The in-depth analysis includes many pre-crash situations with several influencing factors. The factors are e. g. speed of the car, speed of the pedestrian, moving direction and a possible obscuration of the pedestrian by an object. The results comprise also the different situations of adults and children. Furthermore, they include details regarding influence of the lighting conditions (daylight or night) especially with respect to the accident consequences. In fact, more accidents happen at daylight, but fatal accidents are more often at night. A clustering of parameter combinations was found which represents typical accident scenarios. There are six typical accident scenarios which were merged in four test scenarios. The test scenarios are varying the starting position of the pedestrian, the pedestrian size (adult or child) and the speed of the pedestrian, whereas the speed of the car will not be varied. To ensure the independency from used sensing technologies it is necessary to use a suitable dummy. For example, if sensors are based on infrared, the dummy should emit the temperature of a human being. The test procedure will identify the collision speed as the key parameter for assessing the effectiveness of the tested system. The collision speed is defined as the reduction between initial test speed of the car and impact speed. The assessment of the speed reduction value regarding the safety benefit, however, will be part of a separate procedure.
A means of assessing the passive safety of automobiles is a desirable instrument for legislative bodies, the automobile industry, and the consumer. As opposed to the dominating motor vehicle assessment criteria, such as engine power, spaciousness, aerodynamics and consumption, there are no clear and generally accepted criteria for assessing the passive safety of cars. The proposed method of assessment combines the results of experimental safety tests, carried out according to existing legally prescribed or currently discussed testing conditions, and a biomechanical validation of the loading values determined in the test. This evaluation is carried out with the aid of risk functions which are specified for individual parts of the body by correlating the results of accident analysis with those obtained by computer simulation. The degree of conformance to the respective protection criterion thus deduced is then weighted with factors which take into account the frequency of occurrence and the severity of the accident on the basis of resulting costs. Each of the test series includes at least two frontal and one lateral crash test against a deformable barrier. The computer-aided analysis and evaluation of the simulation results enables a vehicle-specific overall safety index as well as partial and individual safety values to be determined and plotted graphically. The passive safety provided by the respective vehicle under test can be defined for specific seating positions, special types of accident, or for individual endangered parts of the body.
Today, Euro NCAP is a well established rating system for passive car safety. The significance of the ratings must however be evaluated by comparison with national accident data. For this purpose accidents with involvement of two passenger cars have been taken from the German National Road Accident Register (record years 1998 to 2004) to evaluate the results of the NCAP frontal impact test configuration. Injury data from both drivers involved in frontal car to car collisions have been sampled and have been compared, using a "Bradley Terry Model" which is well established in the area of paired comparisons. Confounders " like mass ratio of the cars involved, gender of the driver, etc. " have been accounted for in the statistical model. Applying the Bradley Terry Model to the national accident data the safety ranking from Euro NCAP has been validated (safety level: 1star <2 star <3 star <4 star). Significant safety differences are found between cars of the 1 and 2 star category as compared to cars of the 3 and 4 star category. The impact of the mass ratio was highly significant and most influential. Changing the mass ratio by an amount of 10% will raise the chance for the driver of the heavier car to get better off by about 18%. The impact of driver gender was again highly significant, showing a nearly 2 times lower injury risk for male drivers. With regard to the NCAP rating drivers of a high rated car are more than 2 times more probable (70% chance) to get off less injured in a frontal collision as compared to the driver of a low rated car.
Europe has benefited from a decreasing number of road traffic fatalities. However, the proportion of older road users increases steadily. In an ageing society, the SENIORS project aims to improve the safe mobility of older road users by determining appropriate requirements towards passive vehicle safety systems. Therefore, the characteristics of road traffic crashes involving the elderly people need to be understood. This paper focuses on car occupants and pedestrians or cyclists in crashes with modern passenger cars. Ten crash databases and four hospital statistics from Europe have been analysed to answer the questions on which body regions are most frequently and severely injured in the elderly, and specific injuries sustained by always comparing older (65 years and above) with midâ€aged road users (25â€64 years). It was found that the body region thorax is of particularly high importance for the older car occupant with injury severities of AIS2 or AIS3+, where as the lower extremities, head and the thorax need to be considered for older pedestrians and cyclists. Further, injury risk functions were provided. The hospital data analysis showed less difference between the age groups. The linkage between crash and hospital data could only be made on a general level as their inclusion criteria were quite different.
Recent accident statistics from the German national database state bicyclists being the second endangered group of vulnerable road users besides pedestrians. With 399 fatalities, more than 14.000 seriously injured and more than 61.000 slightly injured persons on german roads in the year 2011, the group of bicyclists is ranked second of all road user groups (Statistisches Bundesamt, 2012). While the overall bicycle helmet usage frequency in Germany is very low, evidence is given that its usage leads to a significant reduction of severe head injuries. After an estimation of the benefit of bicycle helmet usage as well as an appropriate test procedure for bicyclists, this paper describes two different approaches for the improvement of bicyclist safety. While the first one is focusing on the assessment of the vehicle based protection potential for bicyclists, the second one is concentrating on the safety assessment of bicycle helmets. Within the first part of the study the possible revision of the existing pedestrian testing protocols is being examined, using in depth accident data, full scale simulation and hardware testing. Within the second part of the study, the results of tests according to supplemental test procedures for the safety assessment of bicycle helmets developed by the German Federal Highway Research Institute (BASt) are presented. An additional full scale test performed at reduced impact speed proves that measures of active vehicle safety as e.g. braking before the collision event do not necessarily always lead to a reduction of injury severity.
New vehicle types are extensively tested to check almost all factors that influence ride and handling. With reference to the Association of German Car Tuners" (VDAT e.V.) valuations, approximately 10% of all cars in Germany are being modified by their owners. 28 % of those modifications" sales are divergent wheel-tire combinations, 13 % are tuning measures on the chassis suspension or wheel spacers. In almost all cases the singular modifications present a general permission for specific vehicles they have been tested in. Combined tuning measures, however, are often checked by just one inspector, following a procedure of mostly subjective assessment criteria. Today, critical attributes are only being observed, in case a vehicle is involved in an accident and the modifications are identified as crash causal factors or as a cofactor on the development of a crash. For the first time, a field study allows a survey of safety affecting chassis modifications. The test layout has to comply with some basic conditions. Different vehicle concepts with a wide margin of modifications are required to get a high transferability of the results. A total amount of more than 150 tested vehicles serves the same purpose. The tests are limited concerning the installation time of measurement techniques and the requirement that no damage, defilement or immoderate wear of the vehicles are accepted by their owners. Due to such factors as well as the driver Ìs acceptance, the vehicles are controlled by its owners instead of robots or test drivers. For keeping down the driver- influence, the lane has narrow boundaries and the driver has to drive in strictly adherence to the given instructions. After gathering all modifications, as well as static and kinematic parameters like the toe and camber angle, dynamic testing of predominantly lateral dynamics is conducted. Besides standardized tests like the ISO 3888-2 (Obstacle Avoidance) or the ISO 14512 (Braking on Surfaces with Split Coefficient of Friction), to test the influence of modified kingpin offsets caused by wheel spacers, some deviant tests are conducted. Those are required due to the demand of objective test results for road tests with vertical induced stimulation of the chassis suspension. Hence, new tests on corner braking with and without vertical stimulation have been developed. The interpretation of data includes thresholds, e.g. the maximum entrance velocity without hitting cones, on the one hand, and the analysis of characteristics of data concerning time and frequency range, "1-second values" and peak response times on the other hand. Besides the thresholds as indicators for the achievable velocities, which are mainly affected by friction coefficients, the vehicle reaction in the course of time characterizes the vehicle reaction in the threshold range and consequently the operational demands on the driver. The field study has started and promises the first long-range analysis of chassis modifications. The results offer a basis for hypothesis and resultant further test layouts for oncoming studies of the identified critical tuning measures.
Within this paper different European accident data sources were used to investigate the causations and backgrounds of road traffic accidents with pedestrians. Analyses of high level national data and in-depth accident data from Germany and Great Britain was used to confirm and refine preliminary accident scenarios identified from other sources using a literature review. General observations made included that a high proportion of killed or seriously injured pedestrian casualties impacted by cars were in "dark" light conditions. Seven accident scenarios were identified (each divided into "daylight" and "dark" light conditions) which included the majority of the car front-to-pedestrian crash configurations. Test scenarios were developed using the identified accident scenarios and relevant parameters. Hypothetical parameters were derived to describe the performance of pedestrian pre-crash systems based on the assumption that these systems are designed to avoid false positives as a very high priority, i.e. at virtually all costs. As result, three "Base Test Scenarios" were selected to be developed in detail in the AsPeCSS project. However, further Enhanced Test Scenarios may be needed to address environmental factors such as darkness if it is determined that system performance is sensitive to these factors. Finally, weighting factors for the accident scenarios for Europe (EU-27) were developed by averaging and extrapolation of the available data. This paper represents interim results of Work Package 1 within the AsPeCSS project.
In Germany the number of casualties in passenger car to pedestrian crashes has been reduced by a considerable amount of 40% as regards fatalities and 25% with regard to seriously injured pedestrians since the year 2001. Similar trends can be seen in other European countries. The reasons for that positive development are still under investigation. As infrastructural or behavioral changes do in general take a longer time to be effective in real world, explanations related to improved active and passive safety of passenger vehicles can be more relevant in providing answers for this trend. The effect of passive pedestrian protection " specified by the Euro NCAP pedestrian test result " is of particular interest and has already been analyzed by several authors. However, the number of vehicles with some valid Euro NCAP pedestrian score (post 2002 rating) was quite limited in most of those studies. To overcome this problem of small datasets German National Accident Records have been taken to investigate a similar objective but now based on a much bigger dataset. The paper uses German National Accident Records from the years 2009 to 2011. In total 65.140 records of pedestrian to passenger car crashes have been available. Considering crash parameters like accident location (rural / urban areas) etc., 27.143 of those crashes have been classified to be relevant for the analysis of passive pedestrian safety. In those 27.143 records 7.576 Euro NCAP rated vehicles (post 2002 rating) have been identified. In addition it was possible to identify vehicles which comply with pedestrian protection legislation (2003/102/EG) where phase 1 came into force in October 2005. A significant correlation between Euro NCAP pedestrian score and injury outcome in real-life car to pedestrian crashes was found. Comparing a vehicle scoring 5 points and a vehicle scoring 22 points, pedestrians" conditional probability of getting fatally injured is reduced by 35% (from 0.58% to 0.37%) for the later one. At the same time the probability of serious injuries can be reduced by 16% (from 27.4% to 22.9%). No significant injury reducing effect, associated with the introduction of pedestrian protection legislation (phase 1) was detected. Considerable effects have also been identified comparing diesel and gasoline cars. Higher engine displacements are associated with a lower injury risk for pedestrians. The most relevant parameter has been "time of accident", whereas pedestrians face a more than 2 times higher probability to be fatally injured during night and darkness as compared to daytime conditions.