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Since 2005 the German In-Depth Accident Study (GIDAS) also records aspects of active vehicle safety. This is done because vehicles are fitted with an increasing number of active safety devices which have undoubtedly an influence on the number, severity and course of accidents. Accident researchers expect that collecting active safety data will facilitate to assess and quantify the impact of these and future devices. It is the aim of this paper to outline benefits and limitations associated with the recording of active safety aspects within indepth studies. An overview about possible areas where active safety data can be useful will be given. For that purpose single safety or comfort systems will be selected to estimate the effects of an accident database which includes variables associated with these systems. Questions with regard to the limitations of collecting active safety data will be addressed. Possible items are for example the usability of the data recorded, the real accident cause, the small number of relevant accidents, the time span needed to gather a sufficient dataset, the small share of vehicles equipped with a certain system or different functionalities of systems that are supposed to fall in the same category. As a result user needs for a reasonable data collection of active safety elements will be elaborated.
Insbesondere auf Landstraßen, das heißt außerorts ohne Bundesautobahnen, hat sich in den letzten Jahren ein deutlicher Rückgang bei den Unfällen mit Pkw gezeigt. Von 2001 bis 2005 ist die Zahl der bei Landstraßenunfällen Getöteten von 4.481 auf cirka 3.230 zurückgegangen. Als eine wesentliche Ursache für diese positive Entwicklung wird die stetige Verbesserung der aktiven und passiven Sicherheit von Fahrzeugen angesehen. In der vorliegenden Arbeit wurde untersucht, inwieweit sich in der amtlichen Unfallstatistik Belege für diese Vermutung finden lassen. Ob die Wirkung straßeninfrastrukturseitiger Maßnahmen auf Landstraßenunfälle mit dem gewählten Ansatz analog nachweisbar ist, wurde ebenfalls betrachtet. Der Einfluss fahrzeugseitiger Maßnahmen auf das Unfallgeschehen wurde zum einen für drei Systeme der aktiven Fahrzeugsicherheit Fahrdynamikregelungen (ESP), Bremsassistenten (BAS) und Gasentladungsscheinwerfer (XENON) Ń ermittelt. Zum anderen wurden Verbesserungen der passiven Fahrzeugsicherheit, wie Airbags oder auch die Einführung von Vorschriften zum Beispiel für Frontal- und Seitenaufprall, als Gesamtpaket betrachtet. Darüber hinaus wurden Einflussmöglichkeiten verbesserter Straßeninfrastruktur beziehungsweise -ausstattung erörtert. Für die ausgewählten Sicherheitseinrichtungen wurden geeignete Teilmengen aus dem Unfallgeschehen ausgewählt, bei denen sich der Einfluss der Fahrzeugtechnik erwarten lässt. Diese wurden dann mit Unfallsituationen verglichen, in denen die Maßnahmen keine Wirkung zeigen sollten. Im Einzelnen konnten folgende Ergebnisse aus den Auswertungen des Unfallgeschehens abgeleitet werden: Die Zahl der Unfälle in ESP-relevanten Situationen ist bei neuen Fahrzeugen, in denen ESP zu einem hohen Anteil verbaut ist, deutlich und überproportional zurückgegangen. Hier ist zwischen den Jahren 2000 und 2005 ein Rückgang der Landstraßenunfälle mit Personenschaden und der schwerwiegenden Unfälle mit Sachschaden in Höhe von 28 % eingetreten. Der positive Effekt des ESP zeigt sich auch an der Zahl der schweren Personenschäden (Getötete und Schwerverletzte). Insgesamt ergibt sich für den Rückgang der schweren Personenschäden in ESP-relevanten Situationen auf Landstraßen unter Berücksichtigung der Unfälle älterer Pkw sowie der Unfälle in Vergleichssituationen ein Wert von 13 %. Das Unfallgeschehen in BAS-relevanten Situationen hat sich sowohl für Neufahrzeuge als auch für ältere Fahrzeuge gleichermaßen, aber überproportional verbessert (-31 % Unfälle für BAS-relevante Situationen gegenüber -20 % für nicht BAS-relevante). Ein Sicherheitsvorteil allein durch BAS lässt sich mit den vorliegenden Zahlen somit nicht eindeutig nachweisen. Dass auch ältere Fahrzeuge in der BAS-Situation einen starken Rückgang aufweisen, deutet darauf hin, dass es neben dem BAS weitere Faktoren gibt, die diese Situation positiv beeinflussen, die aber nicht identifiziert sind. Hier könnte ABS, das in der gleichen Situation wirkt wie BAS und auch noch bei älteren Fahrzeugen wachsende Ausstattungsquoten zeigt, eine Rolle spielen. Rückgänge in den Unfallzahlen fallen für Neufahrzeuge in den XENON-relevanten Situationen etwas stärker aus als bei älteren Pkw (-34 % gegenüber -28 %). Daraus lassen sich, vermutlich bedingt durch die geringen Änderungen der Ausstattungsquote, jedoch in dieser Untersuchung keine Sicherheitsvorteile durch Gasentladungslicht ableiten, da der Rückgang gleichermaßen auch in der Vergleichssituation auftritt. Gleichzeitig deutet die Unfallentwicklung in Abhängigkeit vom Fahrzeugalter jedoch darauf hin, dass auch in der XENON-Situation andere Maßnahmen, die zum Beispiel der passiven Fahrzeugsicherheit zuzuordnen sind, wirksam sein müssen. Die Rückgänge der Unfallschwere (Anzahl der Getöteten und Schwerverletzten je 100 Pkw-Fahrer bei Unfällen mit Personenschaden) in Unfällen mit entgegenkommenden Fahrzeugen (relevante Situation für die passive Sicherheit) sind bei Fahrern von Neufahrzeugen am größten (-42 % gegenüber -14 % bei älteren Fahrzeugen). Dies zeigt eindeutig die Wirkung verbesserter Systeme der passiven Fahrzeugsicherheit wie Airbags, Gurtstraffer und -kraftbegrenzer sowie optimierte Fahrzeugstruktur beziehungsweise Fahrgastzelle. Deutliche Rückgänge in der Unfallschwere bei den sonstigen Unfällen von Neufahrzeugen zeigen, dass sich die ständig weiterentwickelte passive Sicherheit auch in anderen Unfallkonstellationen, wie zum Beispiel seitlichen Kollisionen, bewährt. Im Straßeninfrastrukturbereich besteht das Problem, dass die wesentlichen Informationen für den hier gewählten Ansatz zur Ermittlung des Einflusses von Maßnahmen auf das Unfallgeschehen nicht verfügbar sind. Dafür müssten zum einen Daten über die Menge der umgesetzten Maßnahmen im Zeitverlauf vorliegen; zum anderen müsste es eine Vergleichsgruppe geben (Unfälle, die durch die Maßnahme nicht beeinflusst wurden). Maßnahmen und Nicht-Maßnahmen müssten dabei räumlich und/oder zeitlich abgrenzbar sein. Es zeigt sich, dass diese Daten für die meisten Maßnahmen im Infrastrukturbereich nicht vorliegen, sodass mit Hilfe der amtlichen Unfallstatistik keine Untersuchungen zur Wirksamkeit durchgeführt werden können. Hier sind demnach andere Untersuchungsansätze anzuwenden.
Die zukünftige Entwicklung der Straßenverkehrssicherheit und damit auch der Fahrzeugsicherheit wird durch gesellschaftliche, wirtschaftliche, klimapolitische und verkehrspolitische Rand- und Rahmenbedingungen und die voranschreitende technische Entwicklung geprägt sein, die auch für den Gesetzgeber eine Herausforderung darstellen. So wird sich auch das Folgeprogramm des Bundesministeriums für Verkehr, Bau und Stadtentwicklung (BMVBS) für das derzeitige aus dem Jahr 2001 stammende "Programm für mehr Sicherheit im Straßenverkehr" an den Schwerpunkten des "4th Road Safety Action Programme" ausrichten, das im Frühjahr 2010 durch die EU-Kommission veröffentlicht werden soll. Im Prozess zu einer weiteren Verbesserung der Straßenverkehrssicherheit werden unter anderem der demografische Wandel in unserer Gesellschaft, die durch eine erforderliche CO2-Reduktion bedingte Einführung alternativer Antriebe (Elektromobilität) verbunden mit Leichtbau sowie die gesetzlichen Rahmenbedingung (Wiener Abkommen) eine bedeutende Rolle spielen. Die Klärung der gesetzlichen Rahmenbedingungen ist unerlässlich, um die Vision vom unfallfreien Fahren Realität werden lassen zu können.
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.
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.
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.
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.
A methodology to derive precision requirements for automatic emergency braking (AEB) test procedures
(2015)
AEB Systems are becoming important to increase traffic safety. Test procedures in testing for consumer information, manufacturer self-certification and technical regulations are used to ensure a certain minimum performance of these systems. Consequently, test robustness, test efficiency and finally test cost become increasingly important. The key driver for testing effort and test costs is the required repeatable accuracy in a test design - the higher the accuracy, the higher effort and test costs. On the other hand, the performance of active safety systems depends on time discretization in the environment perception and other sub-systems: for instance, typical sensors supply information with a cycle time of 50 - 150 ms. Time discretization results in an inherent spread of system performance, even if the test conditions are perfectly equal. The proposed paper shows a methodology to derive requirements for a test setup (e.g. test repeats, use of driving robots, ...) as function of AEB system generation and rating method (e.g. Euro NCAP points awarded, pass/fail, ...). While the methodology itself is applicable to AEB pedestrian and AEB Car-Car scenarios, due to the lack of sufficient test data for AEB Car-Car, the focus of this paper is on AEB pedestrian scenarios. A simulation model for the performance of AEB Pedestrian systems allows for the systematic variation of the discretization time as well as test condition accuracy. This model is calibrated with test results of 4 production vehicles for AEB Pedestrian, all fully tested by BASt according to current Euro NCAP test protocols. Selected parameters to observe the accuracy of the test setup in case of pedestrian AEB is the calculated impact position of pedestrian on the vehicle front (as if no braking would have occurred), and the test vehicle speed accuracy. These variable was shown in real tests to be repeatable in the range of ± 5 cm and ± 0,25 km/h, respectively, with a fully robotized state of the art test setup. The sensitivity of AEB performance (measured in achieved speed reduction as well as overall rating result according to current Euro NCAP rating methods) towards discretization and the sensitivity of performance towards test accuracy then is compared to identify economic yet robust test concepts. These comparisons show that the available repeatability accuracy of current test setups is more than sufficient for today's AEB system capabilities. Time discretization problems dominate the performance spread especially in test scenarios with a limited pedestrian dummy reveal time (e.g. child behind obstruction, running adult scenarios with low car speeds). This would allow to increase test tolerances to decrease test cost. A methodology which allows to derive the required tolerances in active safety tests might be valuable especially for NCAPs of emerging countries that do not have the necessary equipment (e.g. driving robots, positioning units) available for the full-scale and high tolerance EuroNCAP active safety procedures yet still want to rate active safety systems, thus improving the global safety.
The project UR:BAN "Cognitive assistance (KA)" aims at developing future assistance systems providing improved performance in complex city traffic. New state-of-the-art panoramic sensor technologies now allow comprehensive monitoring and evaluation of the vehicle environment. In order to improve protection of vulnerable road users such as pedestrians and cyclists, a particular objective of UR:BAN is the evaluation and prediction of their behaviour and actions. The objective of subproject "WER" is development support by providing quantitative estimates of traffic collisions at the very start and predict potential in terms of optimized accident avoidance and reduction of injury severity. For this purpose an integrated computer simulation toolkit is being devised based on real world accidents (GIDAS as well as video documented accidents), allowing the prediction of potential effectiveness and future benefit of assistance systems in this accident scenario. Subsequently, this toolkit may be used for optimizing the design of implemented assistance systems for improved effectiveness.
Autonomous Emergency Braking (AEB) systems for pedestrians have been predicted to offer substantial benefit. On this basis, consumer rating programmes, e.g. Euro NCAP, are developing rating schemes to encourage fitment of these systems. One of the questions that needs to be answered to do this fully, is to determine how the assessment of the speed reduction offered by the AEB is integrated with the current assessment of the passive safety for mitigation of pedestrian injury. Ideally, this should be done on a benefit related basis. The objective of this research was to develop a benefit based methodology for assessment of integrated pedestrian protection systems with pre-crash braking and passive safety components. A methodology has been developed which calculates the cost of pedestrian injury expected, assuming all pedestrians in the target population (i.e. pedestrians impacted by the front of a passenger car) are impacted by the car being assessed, taking into account the impact speed reduction offered by the car’s AEB (if fitted) and the passive safety protection offered by the car’s frontal structure. For rating purposes, this cost can be normalised by comparing it to the cost calculated for selected cars. The methodology uses the speed reductions measured in AEB tests to determine the speed at which each casualty in the target population will be impacted. The injury to each casualty is then calculated using the results from standard Euro NCAP pedestrian impactor tests and injury risk curves. This injury is converted into cost using ‘Harm’ type costs for the body regions tested. These costs are weighted and summed. Weighting factors were determined using accident data from Germany and GB and the results of a benefit analysis performed by the EU FP7 AsPeCSS project. This resulted in German and GB versions of the methodology. The methodology was used to assess cars with good, average and poor Euro NCAP pedestrian ratings, with and without a current AEB system fitted. It was found that the decrease in casualty injury cost achieved by fitting an AEB system was approximately equivalent to that achieved by increasing the passive safety rating from poor to average. Also, it was found that the assessment was influenced strongly by the level of head protection offered in the scuttle and windscreen area because this is where head impact occurs for a large proportion of casualties. The major limitation within the methodology is the assumption used implicitly during weighting. This is that the cost of casualty injuries to body areas, such as the thorax, not assessed by the headform and legform impactors, and other casualty injuries such as those caused by ground impact, are related linearly to the cost of casualty injuries assessed by the impactors. A methodology for assessment of integrated pedestrian protection systems was developed. This methodology is of interest to consumer rating programmes which wish to include assessment of these systems. It also raises the interesting issue if the head impact test area should be weighted to reflect better real-world benefit.