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In the paper it is investigated to what extend one can extrapolate the detailed accident database GIDAS (German In-Depth Accident Study), with survey area Hanover and Dresden region, to accident behavior in other regions and countries within Europe and how such an extrapolation can be implemented and evaluated. Moreover, it is explored what extent of accident data for the target country is necessary for such an extrapolation and what can be done in situations with sparse and low accident information in a target region. It will be shown that a direct transfer of GIDAS injury outcomes to other regions does not lead to satisfactory results. But based on GIDAS and using statistical decision tree methods, an extrapolation methodology will be presented which allows for an adequate prediction of the distribution of injury severity in severe traffic accidents for European countries. The method consists essentially of a separation of accidents into well-described subgroups of accidents within which the accident severity distribution does not vary much over different regions. In contrast the distribution over the various subgroups of accidents typically is rather different between GIDAS and the target. For the separation into the subgroups meaningful accident parameters (like accident type, traffic environment, type of road etc.) have been selected. The developed methodology is applied to GIDAS data for the years 1999-2012 and is evaluated with police accident data for Sweden (2002 to 2012) and the United Kingdom (2004 to 2010). It is obtained that the extrapolation proposal has good to very good predictive power in the category of severe traffic accidents. Moreover, it is shown that iterative proportional fitting enables the developed extrapolation method to lead to a satisfactory extrapolation of accident outcomes even to target regions with sparse accident information. As an important potential application of the developed methodology the a priori extrapolation of effects of (future) safety systems, the operation of which can only be well assessed on the basis of very detailed GIDAS accident data, is presented. Based on the evaluation of the presented extrapolation method it will be shown that GIDAS very well represents severe accidents, i.e. accidents with at least one severely or fatally injured person involved, for other countries in Europe. The developed extrapolation method reaches its limits in cases for which only very little accident information is available for the target region.
Cost benefit analysis
(2014)
Although the number of road accident casualties in Europe is falling the problem still remains substantial. In 2011 there were still over 30,000 road accident fatalities [EC 2012]. Approximately half of these were car occupants and about 60 percent of these occurred in frontal impacts. The next stage to improve a car- safety performance in frontal impacts is to improve its compatibility for car-to-car impacts and for collisions against objects and HGVs. Compatibility consists of improving both a car- self and partner protection in a manner such that there is good interaction with the collision partner and the impact energy is absorbed in the car- frontal structures in a controlled way which results in a reduction of injuries. Over the last ten years much research has been performed which has found that there are four main factors related to a car- compatibility [Edwards 2003, Edwards 2007]. These are structural interaction potential, frontal force matching, compartment strength and the compartment deceleration pulse and related restraint system performance. The objective of the FIMCAR FP7 EC-project was to develop an assessment approach suitable for regulatory application to control a car- frontal impact and compatibility crash performance and perform an associated cost benefit analysis for its implementation.
Die UNECE Regelung R58 regelt die Beschaffenheit und die Installation von Heckunterfahrschutzsystemen an schweren Güterkraftfahrzeugen, deren Ziel die Verbesserung der Kompabilität zwischen Pkw-Frontstrukturen und Lkw-Hecks ist. Dennoch verunglücken laut amtlicher Unfallstatistik allein in Deutschland rund 30 Pkw-Insassen in Heckauffahrunfällen auf Lkw tödlich, da diese Vorrichtungen hinsichtlich Einbauhöhe und Steifigkeit den Anforderungen des realen Unfallgeschehens nicht genügen. Das Ziel dieser Studie ist eine quantitative Abschätzung der möglichen Reduzierung der Verletzungsschwere mit Hilfe eines statistischen Modells, die durch eine Anpassung der geltenden Bestimmungen und die damit verbundenen technischen Veränderungen des bereits vorgeschriebenen Heckunterfahrschutzes zu erreichen wäre. In einer Nutzen-Kosten-Analyse wird die Wirtschaftlichkeit dieser Modifizierungen mit einem idealen Notbremsassistenten verglichen. Die Untersuchung orientiert sich dabei an den aktuell in der UN-ECE WP29/GRSG in Genf diskutierten Vorschlägen zur Anpassung der ECE-R58. Das verwendete ordinale Probit-Modell stellt einen Zusammenhang zwischen der Verletzungsschwere im auffahrenden PKW und erklärenden Größen her, in diesem Fall der kinetischen Energie des unterfahrenden Pkws und der strukturellen lnteraktion zwischen Lkw-Heck und Pkw-Front. Diese Maßnahmen könnten demnach 53 - 78% der Getöteten sowie 27 - 49% der Schwerverletzten bei diesen Unfallkonstellationen reduzieren, was pro Jahr 20 Getöteten und 95 Schwerverletzten entsprechen würde. Somit würde eine Modifikation einer bestehenden passiven Schutzmaßnahme an jährlich 100.000 neuzugelassenen Lkw und Anhängern bereits 20 Getötete adressieren. Im Vergleich dazu müssten jährlich 3 Millionen Pkw mit zusätzlicher Sensorik und Aktuatorik für einen idealen Notbremsassistenten ausgestattet werden, um im Idealfall alle Heckauffahrunfälle von Pkw auf andere Pkw oder Lkw und damit 53 Getötete zu vermeiden. Daher fällt auch das Nutzen-Kosten-Verhältnis deutlich zugunsten des verbesserten Heckunterfahrschutzes aus.
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.
It is commonly agreed that active safety will have a significant impact on reducing accident figures for pedestrians and probably also bicyclists. However, chances and limitations for active safety systems have only been derived based on accident data and the current state of the art, based on proprietary simulation models. The objective of this article is to investigate these chances and limitations by developing an open simulation model. This article introduces a simulation model, incorporating accident kinematics, driving dynamics, driver reaction times, pedestrian dynamics, performance parameters of different autonomous emergency braking (AEB) generations, as well as legal and logical limitations. The level of detail for available pedestrian accident data is limited. Relevant variables, especially timing of the pedestrian appearance and the pedestrian's moving speed, are estimated using assumptions. The model in this article uses the fact that a pedestrian and a vehicle in an accident must have been in the same spot at the same time and defines the impact position as a relevant accident parameter, which is usually available from accident data. The calculations done within the model identify the possible timing available for braking by an AEB system as well as the possible speed reduction for different accident scenarios as well as for different system configurations. The simulation model identifies the lateral impact position of the pedestrian as a significant parameter for system performance, and the system layout is designed to brake when the accident becomes unavoidable by the vehicle driver. Scenarios with a pedestrian running from behind an obstruction are the most demanding scenarios and will very likely never be avoidable for all vehicle speeds due to physical limits. Scenarios with an unobstructed person walking will very likely be treatable for a wide speed range for next generation AEB systems.
Although the number of road accident casualties in Europe (EU27) is falling the problem still remains substantial. In 2011 there were still over 30,000 road accident fatalities. Approximately half of these were car occupants and about 60 percent of these occurred in frontal impacts. The next stage to improve a car's safety performance in frontal impacts is to improve its compatibility. The objective of the FIMCAR FP7 EU-project was to develop an assessment approach suitable for regulatory application to control a car's frontal impact and compatibility crash performance and perform an associated cost benefit analysis for its implementation. This paper reports the cost benefit analyses performed to estimate the effect of the following potential changes to the frontal impact regulation: • Option 1 " No change and allow current measures to propagate throughout the vehicle fleet. • Option 2 " Add a full width test to the current offset Deformable Barrier (ODB) test. • Option 3 " Add a full width test and replace the current ODB test with a Progressive Deformable Barrier (PDB) test. For the analyses national data were used from Great Britain (STATS 19) and from Germany (German Federal Statistical Office). In addition in-depth real word crash data were used from CCIS (Great Britain) and GIDAS (Germany). To estimate the benefit a generalised linear model, an injury reduction model and a matched pairs modelling approach were applied. The benefits were estimated to be: for Option 1 "No change" about 2.0%; for Option 2 "FW test" ranging from 5 to 12% and for Option 3 "FW and PDB tests" 9 to 14% of car occupant killed and seriously injured casualties.
A biofidelic flexible pedestrian legform impactor (FlexPLI) has been developed from the year 2000 onwards and evaluated by a technical evaluation group (Flex-TEG) of UN-ECE GRSP. A recently established UN-ECE GRSP Informal Group on GTR9 Phase 2 is aiming at introducing the FlexPLI within world-wide regulations on pedestrian safety (Phase 2 of GTR No. 9 as well as the new UN regulation 127 on pedestrian safety) as a test tool for the assessment of lower extremity injuries in lateral vehicle-to-pedestrian accidents. Besides, the FlexPLI has already been introduced within JNCAP and is on the Euro NCAP roadmap for 2014. Despite of the biofidelic properties in the knee and tibia sections, several open issues related to the FlexPLI, like the estimation of the cost benefit, the feasibility of vehicle compliance with the threshold values, the robustness of the impactor and of the test results, the comparability between prototype and production level and the finalization of certification corridors still needed to be solved. Furthermore, discussions with stakeholders about a harmonized lower legform to bumper test area are still going on. This paper describes several studies carried out by the Federal Highway Research Institute (BASt) regarding the benefit due to the introduction of the FlexPLI within legislation for type approval, the robustness of test results, the establishment of new assembly certification corridors and a proposal for a harmonized legform to bumper test area. Furthermore, a report on vehicle tests that previously had been carried out with three prototype legforms and were now being repeated using legforms with serial production status, is given. Finally, the paper gives a status report on the ongoing simulation and testing activities with respect to the development and evaluation of an improved test procedure with upper body mass for assessing pedestrian femur injuries.
The European Enhanced Vehicle-safety Committee wants to promote the use of more biofidelic child dummies and biomechanical based tolerance limits in regulatory and consumer testing. This study has investigated the feasibility and potential impact of Q-dummies and new injury criteria for child restraint system assessment in frontal impact. European accident statistics have been reviewed for all ECE-R44 CRS groups. For frontal impact, injury measures are recommended for the head, neck, chest and abdomen. Priority of body segment protection depends on the ECE-R44 group. The Q-dummy family is able to reflect these injuries, because of its biofidelity performance and measurement capabilities for these body segments. Currently, the Q0, Q1, Q1.5, Q3 and Q6 are available representing children of 0, 1, 1.5, 3 and 6 years old. These Q-dummies cover almost all dummy weight groups as defined in ECE-R44. Q10, representing a 10 year-old child, is under development. New child dummy injury criteria are under discussion in EEVC WG12. Therefore, the ECE-R44 criteria are assessed by comparing the existing P-dummies and new Q-dummies in ECE-R44 frontal impact sled tests. In total 300 tests covering 30 CRSs of almost all existing child seat categories are performed by 11 European organizations. From this benchmark study, it is concluded that the performance of the Q-dummy family is good with respect to repeatability of the measurement signals and the durability of the dummies. Applying ECE-R44 criteria, the first impression is that results for P- and Q-dummy are similar. For child seat evaluation the potential merits of the Q-dummy family lie in the extra measurement possibilities of these dummies and in the more biofidelic response.
In spite of today's highly sophisticated crash test procedures like the different NCAP programs running world-wide, bad real world crash performance of cars is still an issue. There are crash situations which are not sufficiently represented by actual test configurations. This is especially true for car to car, as well as for car to object impacts. The paper describes reasons for this bad performance. The reasons are in principal bad structural interaction between the car and its impact partners (geometric incompatibility), unadjusted front end stiffness (stiffness incompatibility) and collapse of passenger compartments. To show the efficiency of improving cars' structural behaviour in accidents with different impact partners an accident data analysis has been taken out by members of European Project VC-COMPAT. Accident data analysis has shown that in Germany between 15,000 and 20,000 of the now severely injured car occupants might get less injured and between 600 and 900 car occupant fatalities might be saved. Similar results arise for the UK.