23rd ESV Conference 2013
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Thoracic injuries are one of the main causes of fatally and severely injured casualties in car crashes. Advances in restraint system technology and airbags may be needed to address this problem; however, the crash test dummies available today for studying these injuries have limitations that prevent them from being able to demonstrate the benefits of such innovations. THORAX-FP7 was a collaborative medium scale project under the European Seventh Framework. It focused on the mitigation and prevention of thoracic injuries through an improved understanding of the thoracic injury mechanisms and the implementation of this understanding in an updated design for the thorax-shoulder complex of the THOR dummy. The updated dummy should enable the design and evaluation of advanced restraint systems for a wide variety (gender, age and size) of car occupants. The hardware development involved five steps: 1) Identification of the dominant thoracic injury types from field data, 2) Specification of biomechanical requirements, 3) Identification of injury parameters and necessary instrumentation, 4) Dummy hardware development and 5) Evaluation of the demonstrator dummy. The activities resulted in the definition of new biofidelity and instrumentation requirements for an updated thorax-shoulder complex. Prototype versions were realised and implemented in three THOR dummies for biomechanical evaluation testing. This paper documents the hardware developments and biomechanical evaluation testing carried out.
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.
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.
The objective was to develop and validate a crash trolley (reference vehicle) equipped with a compartment and a full restraint system for driver and front seat passenger which can be used in full scale crash testing. Furthermore, the crash trolley should have a suspension to show rotation and nick effects similar to real vehicles. Within the development phase the reference vehicle was build based on a European family car. Special attention was needed to provide appropriate strength to the trolley and its suspension. The reference vehicle is equipped with a restraint system consisting of airbags, pedals, seats, dashboard, and windscreen. On the front of the vehicle different crash barriers can be installed to provide miscellaneous deceleration pulses. For the validation phase a series of low and high speed crash tests with HIII dummies were conducted and compared with full scale tests. For the comparison deceleration pulse, dummy numbers and vehicle movement were analyzed. Validation tests with velocities up to 60 km/h showed promising results. The compartment and the suspension systems stayed stable. Rotation effects were comparable with full scale car crash tests. The airbags and seat belt system worked reasonable. The acceleration pulse compared to an Euro NCAP test had a similar characteristic but was in general slightly lower. After the successful validation the reference vehicle is already in use in different studies in the field of vehicle safety research at BASt.
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.
Since integrated safety systems combine active and passive safety elements in one safety system, it is necessary to define new procedures to evaluate vehicle safety from the overall system point of view. The main goal of the ASSESS project is to develop harmonized and standardized assessment procedures for collision mitigation and avoidance systems. Methods and Data Sources: In ASSESS, procedures are developed for: driver behaviour evaluation, pre-crash system performance evaluation, crash performance evaluation, socio-economic assessment. This paper will concentrate on the activities related to the crash evaluation. The objective is to perform simulations, sled tests and crash tests in order tounderstand the influence of the activation of the pre-crash systems on the occupants" injuries during the crash phase. When a traffic accident is unavoidable, pre-crash systems work on various safety devices in order to improve the vehicle occupants" protection. Braking assistance and adaptive restraint systems are the main pre-crash systems whose effect on the occupants" protection will be described in this paper. Results: The results will be a description of the effect of the activation of the pre-crash systems on the crash phase. Additionally, a set of recommendations for future methodology developments will be delivered. Furthermore, a first approach to the study of the effect of the pre-crash systems activation on the occupants" protection when the impact is unavoidable will be presented. This effect will be quantified using the biomechanical values obtained from the simulation and testing activities and their related injury risks. Simulation and testing activities will consider the following scenarios: - No activation of any pre-crash system, - Activation of one or a combination of several pre-crash systems. In this way, differences in the results obtained from different scenarios will show the effect of each pre-crash system separately during the crash phase. Discussion and Limitations: The set of activities developed in this research project is limited by the fact that with the given resources only a limited number of vehicle models could be investigated. In addition, there are also limitations related to the injury risk curves and the passive safety tools currently on the market. Conclusion and Relevance to session submitted: The paper will present a complete analysis of the effect of pre-crash systems during the crash phase when the impact is unavoidable. Details, limitations and first application experience based on a few examples will be discussed. Currently, there is not any regulation, assessment program, or other similar official procedure able to assess pre-crash systems during the crash phase. This project comprises phases of traffic accidents which have been historically analysed separately, and aims to evaluate them taking into account their interrelationship. ASSESS is one of the first European projects which deals in depth with the concept of integrated safety, defining methodologies to analyse vehicle safety from a global point of view.
It is well known that most accidents with pedestrians are caused by the driver not being alert or misinterpreting the situation. For that reason advanced forward looking safety systems have a high potential to improve safety for this group of vulnerable road users. Active pedestrian protection systems combine reduction of impact speed by driver warning and/or autonomous braking with deployment of protective devices shortly before the imminent impact. According to the Euro NCAP roadmap the Autonomous Emergency Braking system tests for Pedestrians Protection will be set in force from 2016 onwards. Various projects and organisations in Europe are developing performance tests and assessment procedures as accompanying measures to the Euro NCAP initiative. To provide synthesised input to Euro NCAP so-called Harmonisation Platforms (HP-) have been established. Their main goal is to foster exchange of information on key subjects, thereby generating a clear overview of similarities and differences on the approaches chosen and, on that basis, recommend on future test procedures. In this paper activities of the Harmonisation Platform 2 on the development of Test Equipment are presented. For the testing targets that mimic humans different sensing technologies are required. A first set of specifications for pedestrian targets and the propulsion systems as collected by Harmonisation Platform 2 are presented together with a first evaluation for a number of available tools.
Although the bus belongs to the safest traffic means, single accidents can be particularly severe and concern many passengers. Especially in case of fires a high number of injured and killed persons can be the outcome. Fire safety of buses therefore is of high importance. With the increase of synthetic and plastic materials as a material for the interior equipment of buses and coaches because of their ood mechanical properties combined with low weight, the question arises whether the safety level has decreased in case of a fire during the last years - also compared to other means of transport. Because of the combustible plastics and their ability to release a high amount of heat the main fire load in buses is no longer the fuel but the plastic materials which are also often easy to ignite. Besides the flammability of the equipments, the production of smoke, the smoke development and propagation and its toxicity for the people as well as the testing methods and limit values are of interest. For those reasons research projects were initiated on behalf of the German Federal Highway Research Institute. At the one hand the fire behavior of coach interiors was examined in general focusing on fire propagation as well as fire detection and signalling. As result, recommendations with regard to early fire detection systems for the engine compartments and on-board extinguishing equipment were elaborated. At the other hand research is carried out to examine heat release, smoke, smoke propagation and its toxicity due to burning bus interior materials. The paper describes which effective and economically reasonable fire safety requirements for interiors of buses would improve the current situation. Proposals for amendments of current requirements are recommended including the specification of appropriate limit values. In particular, it is taken into consideration which reasonable fire safety standards from other transport sectors, especially the rail sector, should be transferred to buses.
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.
To improve vehicle safety in frontal collisions, the crash compatibility between the colliding vehicles is crucial. Compatibility aims to improve both the self and partner protection properties of vehicles. Although compatibility has received worldwide attention for many years, no final assessment approach has been defined. Within the Frontal Impact and Compatibility Assessment Research (FIMCAR) project, different frontal impact test procedures (offset deformable barrier [ODB] test as currently used for Economic Commission for Europe [ECE] R94, progressive deformable barrier test as proposed by France for a new ECE regulation, moveable deformable barrier test as discussed worldwide, full-width rigid barrier test as used in Federal Motor Vehicle Safety Standard [FMVSS] 208, and full-width deformable barrier test) were analyzed regarding their potential for future frontal impact legislation. The research activities focused on car-to-car frontal impact accidents based on accident investigations involving newer cars. Test procedures were developed with both a crash test program and numerical simulations. The proposal from FIMCAR is to use a full-width test procedure with a deformable element and compatibility metrics in combination with the current offset test as a frontal impact assessment approach that also addresses compatibility. By adding a full-width test to the current ODB test it is possible to better address the issues of structural misalignment and injuries resulting from high acceleration accidents as observed in the current fleet. The estimated benefit ranges from a 5 to 12 percent reduction of fatalities and serious injuries resulting from frontal impact accidents. By using a deformable element in the full-width test, the test conditions are more representative of real-world situations with respect to acceleration pulse, restraint system triggering time, and deformation pattern of the front structure. The test results are therefore expected to better represent real-world performance of the tested car. Furthermore, the assessment of the structural alignment is more robust than in the rigid wall test.