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The UN Regulation No. 79 is going to be amended to allow automatically commanded steering functions (ACSF) at speeds above 10 km/h. Hence, requirements concerning the approval of automatically performed steering manoeuvres have to be set in order to allow safe use of automatic steering on public roads as well as improve overall road safety for the driver and the surroundings. By order of the German Federal Ministry of Transport and Digital Infrastructure (BMVI), BASt developed and verified physical test procedures for automatic steering to be implemented in UN Regulation No. 79. The usability of currently available test tools was examined. The paper at hand describes these test procedures and presents results from verification tests. The designated tests are divided in three sections: functionality tests, verifications for the transition of control and emergency tests. System functionality tests are auto matic lane keeping, automatic lane change and an automatic abort of an initiated lane change due to traffic. Those tests check if the vehicle remains in its lane (under normal operating conditions), is able to perform safe automatic lane change manoeuvres and if it considers other road users during its manoeuvres. Transition tests examine the vehicle's behaviour when the driver fails to monitor the system and in situations when the system has to hand over the steering control back to the driver. For instance these tests provoke driver-in-the-loop requests by approaching system boundary limitations, like missing lane markings, surpassing maximum lateral acceleration in a bend or even a major system failure. Even further the driver and his inputs are monitored and if the system detects that he is overriding system actions or contrary want to quit the driving task and unfastens the seat belt, it has to shut down and put the human back into manually control and the responsibility of driving. The last series of test consists of two emergency situations in which the system has to react to a time critical event: A hard decelerating vehicle and a stationary vehicle in front both with no lane change possibility for the ACSF vehicle. Some of the tests, especially the emergency manoeuvres, require special target vehicles and propulsion systems. Since no fully automatic steering vehicles are available, a current Mercedes E-Class with Mercedes' "drive pilot" system was used. It was shown that the vehicle is automatically able to brake to a full stop towards a static Euro NCAP target from partial-automatic driving at 90 km/h, that it could brake towards a rapidly decelerating lead vehicle when travelling at 70 km/h, that it was able during partially automatic driving to remain in its lane in normal operation conditions and to perform a automatic (driver initiated) lane change while surveilling the driver- activities.
Schutz von schwächeren Verkehrsteilnehmern: kommende Anforderungen aus Gesetzgebung und Euro NCAP
(2017)
Systeme der aktiven Fahrzeugsicherheit, insbesondere Notbremsassistenzsysteme und automatische Notbremssysteme, haben in den letzten zwei Dekaden große technische Fortschritte gemacht, und das im Wesentlichen ohne "Druck" von Gesetzgeber oder unabhängigen Testorganisationen " diese können aber durch passende Anforderungen den Vormarsch der Systeme in die Breite und die Ausnutzung von ansonsten für den Hersteller vielleicht nicht wirtschaftlichen Potentialen unterstützen. Dieser Bericht hat das Ziel, einen Überblick über die kommenden Anforderungen an Schutzsysteme für schwächere Verkehrsteilnehmer zu geben und diese Anforderungen in den Kontext Euro NCAP (=welchen Einfluss haben diese Anforderungen auf die Gesamtbewertung?) sowie Gesetzgebung (schwächere Anforderungen, aber dafür ein Markteintrittskriterium) zu stellen: - Anforderungen und Testprozeduren für Notbremsassistenz Fahrradunfälle 2018 und 2020 in Euro NCAP; - Anforderungen und Testprozeduren für Notbremsassistenz bei Nachtunfällen mit Fußgängern in Euro NCAP 2018; - Anforderungen und Testprozeduren für Abbiegeassistenzsysteme zum Schutz von Radfahrern in Unfallsituationen mit rechtsabbiegenden Lkw innerhalb der Fahrzeugtypgenehmigung.
Except for corrective steering functions automatic steering is up to now only allowed at speeds up to 10 km/h according to UN Regulation No. 79. Progress in automotive engineering with regard to driver assistance systems and automation of driving tasks is that far that it would be technically feasible to realise automatically commanded steering functions also at higher vehicle speeds. Besides improvements in terms of comfort these automated systems are expected to contribute to road traffic safety as well. However, this safety potential will only be exhausted if automated steering systems are properly designed. Especially possible new risks due to automated steering have to be addressed and reduced to a minimum. For these reasons work is currently ongoing on UNECE level with the aim to amend the regulation dealing with provisions concerning the approval of steering equipment. It is the aim to revise requirements for automatically commanded steering functions (ACSF) so that they can be approved also for higher speeds if certain performance requirements are fulfilled. The paper at hand describes the derivation of reasonable system specifications from an analysis of relevant driving situations with an automated steering system. Needs are explained with regard to covering normal driving, sudden unexpected critical events, transition to manual driving, driver availability and manoeuvres to reach a state of minimal risk. These issues form the basis for the development of test procedures for automated steering to be implemented in international regulations. This holds for system functionalities like automatic lane keeping or automatic lane change as well as for addressing transition situations in which the system has to hand over steering to the driver or addressing emergency situations in which the system has to react instead of the driver.
Accidents between right turning trucks and straight driving cyclists often show massive consequences. Accident severity in terms of seriously or fatally injured cyclists that are involved is much higher than in accidents of other traffic participants in other situations. It seems clear that adding additional mirrors will very likely not improve the situation. At ESV 2015, a methodology to derive test procedures and first test cases as well as requirements for a driver assist system to address blind spot accidents has been presented. However, it was unclear if and how testing of these cases is feasible, to what extent characteristics of different truck concepts (e.g. articulated vehicles, rigid vehicles) influence the test conduction and outcome, and what tolerances should be selected for the different variables. This work is important for the acceptance of a draft regulation in the UN working group on general safety. In the meantime, three test series using a single tractor vehicle, a tractor-semitrailer combination and a rigid vehicle have been conducted. The test tools (e.g. surrogate devices) have been refined. A fully crashable, commercially available bicycle dummy has been tested. If used correct, this dummy does follow a straight line quite precisely and it does not cause any damage to the truck under test in case of accidental impact. The dummy specifications are freely available. During testing, the different vehicle categories resulted in different trajectories being driven. Articulated vehicle combinations did first execute a turn into the opposite direction, and on the other hand, single tractor vehicles did behave comparable to passenger cars. A possible solution to take these behaviors into account is to require the vehicles to drive through a corridor that is narrow for a precise straight-driving phase and extends during the turn. Other investigated parameters are the dummy and vehicle speed tolerances. The results from this research make it possible to draft a regulation for a driver assistance system that helps to avoid blind spot accidents: test cases have been refined, their feasibility has been checked, and corridors for the vehicles and for important parameters (e.g. test speeds) have been set. The test procedure is applicable to all types of heavy goods vehicles. In combination with the accidentology (ESV 2015 paper), the work provides the basis for a regulation for such an assistance system.
One main objective of the EU-Project SENIORS is to provide improved methods to assess thoracic injury risk to elderly occupants. In contribution to this task paired simulations with a THOR dummy model and human body model will be used to develop improved thoracic injury risk functions. The simulation results can provide data for injury criteria development in chest loading conditions that are underrepresented in PMHS test data sets that currently proposed risk functions are based on. To support this approach a new simplified generic but representative sled test fixture and CAE model for testing and simulation were developed. The parameter definition and evaluation of this sled test fixture and model is presented in this paper. The justification and definition of requirements for this test set-up was based on experience from earlier studies. Simple test fixtures like the gold standard sled fixture are easy to build and also to model in CAE, but provide too severe belt-only loading. On the other hand a vehicle buck including production components like airbag and seat is more representative, but difficult to model and to be replicated at a different laboratory. Furthermore some components might not be available for physical tests at later stage. The basis of the SENIORS generic sled test set-up is the gold standard fixture with a cable seat back and foot rest. No knee restraint was used. The seat pan design was modified including a seat ramp. The three-point belt system had a generic adjustable load limiter. A pre-inflated driver airbag assembly was developed for the test fixture. Results of THOR test and simulations in different configurations will be presented. The configurations include different deceleration pulses. Further parameter variations are related to the restraint system including belt geometry and load limiter levels. Additionally different settings of the generic airbag were evaluated. The test set-up was evaluated and optimized in tests with the THOR-M dummy in different test configurations. Belt restraint parameters like D-ring position and load limiter setting were modified to provide moderate chest loading to the occupant. This resulted in dummy readings more representative of the loading in a contemporary vehicle than most available PMHS sled tests reported in the literature. However, to achieve a loading configuration that exposes the occupant to even less severe loading comparable to modern vehicle restraints it might be necessary to further modify the test set-up. The new generic sled test set-up and a corresponding CAE model were developed and applied in tests and simulations with THOR. Within the SENIORS project with this test set-up also volunteer and PMHS as well as HBM simulations are performed, which will be reported in other publications. The test environment can contribute in future studies to the assessment of existing and new frontal impact dummies as well as dummy improvements and related instrumentation. The test set-up and model could also serve as a new standard test environment for PMHS and volunteer tests as well as HBM simulations.
Für eine Reihe von EU Regelungen im Bereich Fahrzeugsicherheit erlaubt eine Verordnung bereits seit dem Jahr 2010 virtuelles Testen für die Typzulassungsprüfung. Technische Details bzw. konkrete Prozeduren für spezifische Regelungen sind in dieser Verordnung jedoch nicht enthalten. Das Hauptziel des europäischen Projekts IMVITER (lmplementation of Virtual Testing in Safety Regulations) war es, basierend auf der neuen Verordnung ein virtuelles Testverfahren auszuarbeiten und dabei offene Fragen zu berücksichtigen. Um die im Projekt-Konsortium unter Berücksichtigung der Anliegen aller Interessensgruppen wie Autohersteller, Zulassungsbehörden und technischer Dienste erarbeiteten offenen Punkte zu adressieren, wurde ein generisches Flussdiagramm entwickelt, das den Ablauf einer virtuell basierten Typprüfung darstellt. ln diesem Diagramm ist der virtuelle Typgenehmigungsprozess in drei aufeinander folgende Phasen aufgeteilt, die Verifikations-, Validierungs- und Typgenehmigungsphase. Von entscheidender Bedeutung ist die Phase der Validierung des Simulationsmodells, für die im IMVITER-Projekt eine Methodik vorgeschlagen wurde. Mit der im Projekt vorgeschlagenen Validierungsmethode ist kein Austausch des Simulationsmodells zwischen Fahrzeughersteller und technischem Dienst notwendig, so dass die Vertraulichkeit von Betriebsgeheimnissen nicht gefährdet ist. Zur Validierung des Modells werden jedoch immer Versuche notwendig sein. Dies gilt sowohl für die Überpruefung von passiven als auch aktiven Fahrzeugsicherheitssystemen. Eine zusammenfassende Betrachtung der Erfahrungen aus dem IMVITER-Projekt ergab, dass mit der Einführung von virtuellem Testen keine Erhöhung der Anforderungen an die Fahrzeugsicherheit bzgl. bestehender Regelungen verbunden sein sollte. Jedoch werden auch weiterhin neue zusäztliche Regelungen erforderlich sein, da sich das Unfallgeschehen und die Fahrzeugtechnologie weiterentwickeln und ändern werden. Diese sollten von Beginn an die Möglichkeiten des virtuellen Testens nutzen, insbesondere bei Testverfahren für neue Technologien, z.B. aktiver Fahrzeugsicherheitssysteme. Hier bieten virtuelle Testverfahren nicht nur eine Kosten- oder Zeitersparnis, sondern ermöglichen teilweise erst die sinnvolle Abprüfung von neuen Sicherheitssystemen, die mit aktuellen auf Hardware-Test basierenden Verfahren überhaupt nicht möglich wären.
Die Level kontinuierlicher Fahrzeugautomatisierung sind unter Fahrerassistenzexperten weithin bekannt und erleichtern das Verständnis. Sie können aber nicht Fahrzeugautomatisierung insgesamt zufriedenstellend beschreiben: Insbesondere temporär intervenierende Funktionen, die in unfallnahen Situationen eingreifen, können offensichtlich nicht nach dem Level kontinuierlicher Fahrzeugautomatisierung beschrieben werden. Diese beschreiben nämlich die zunehmende Aufgabenverlagerung vom Fahrer zur maschinellen Steuerung bei zunehmendem Automatisierungsgrad. Notbremsfunktionen, beispielsweise, sind offensichtlich diskontinuierlich und nehmen zugleich auf intensive Weise Einfluss auf die Fahrzeugsteuerung. Sie lassen sich gerade nicht sinnvoll nach dem Level kontinuierlicher Fahrzeugautomatisierung beschrieben. Das Ergebnis kann indes nicht zufriedenstellen. Die fehlende Sichtbarkeit dieser Funktionen wird ihrer Bedeutung für die Verkehrssicherheit nicht gerecht. Daher wird im Beitrag, um ein vollständiges Bild der Fahrzeugautomatisierung zu erlangen, ein umfassender Ansatz zur Beschreibung verfolgt, der sich auf oberster Ebene nach Wirkweise unterscheidet. Auf dieser Basis lassen sich sowohl informierende und warnende Funktionen als auch solche, die nur temporär in unfallgeneigten Situationen intervenieren, im Detail beschrieben. Das ermöglicht es, eine eigenständige Klassifikation für unfallgeneigte Situationen zu erstellen; dies kann für diese wichtigen Funktionen die eigenständige Sichtbarkeit herstellen, die ihrer Bedeutung gerecht wird.
Die Level kontinuierlicher Fahrzeugautomatisierung sind unter Fahrerassistenzexperten weithin bekannt und erleichtern das Verständnis. Sie können aber nicht Fahrzeugautomatisierung insgesamt zufriedenstellend beschreiben: Insbesondere temporär intervenierende Funktionen, die in unfallnahen Situationen eingreifen, können offensichtlich nicht nach dem Level kontinuierlicher Fahrzeugautomatisierung beschrieben werden. Diese beschreiben nämlich die zunehmende Aufgabenverlagerung vom Fahrer zur maschinellen Steuerung bei zunehmendem Automatisierungsgrad. Notbremsfunktionen, beispielsweise, sind offensichtlich diskontinuierlich und nehmen zugleich auf intensive Weise Einfluss auf die Fahrzeugsteuerung. Sie lassen sich gerade nicht sinnvoll nach dem Level kontinuierlicher Fahrzeugautomatisierung beschreiben. Das Ergebnis kann indes nicht zufriedenstellen: Die fehlende Sichtbarkeit dieser Funktionen wird ihrer Bedeutung für die Verkehrssicherheit nicht gerecht. Daher wird hier, um ein vollständiges Bild der Fahrzeugautomatisierung zu erlangen, ein umfassender Ansatz zur Beschreibung verfolgt, der auf oberster Ebene nach Wirkweise unterscheidet. Auf dieser Basis lassen sich sowohl informierende und warnende Funktionen als auch solche, die nur temporär in unfallgeneigten Situationen intervenieren, im Detail beschreiben. Das ermöglicht es, eine eigenständige Klassifikation für unfallgeneigte Situationen zu erstellen. Dies kann für diese wichtigen Funktionen die eigenständige Sichtbarkeit herstellen, die ihrer Bedeutung gerecht wird.
The levels of continuous vehicle automation have become common knowledge. They facilitate overall understanding of the issue. Yet, continuous vehicle automation described therein does not cover "automated driving" as a whole: Functions intervening temporarily in accident-prone situations can obviously not be classified by means of continuous levels. Continuous automation describes the shift in workload from purely human driven vehicles to full automation. Duties of the driver are assigned to the machine as automation levels rise. Emergency braking, e.g., is obviously discontinuous and intensive automation. It cannot be classified under this regime. The resulting absence of visibility of these important functions cannot satisfy " especially in the light of effect they take on traffic safety. Therefore, in order to reach a full picture of vehicle automation, a comprehensive approach is proposed that can map out different characteristics as "Principle of Operation" at top level. On this basis informing and warning functions as well as functions intervening only temporarily in near-accident situations can be described. To reach a complete picture, levels for the discontinuous, temporarily intervening functions are proposed " meant to be the counterpart of the continuous levels already in place. This results in a detailed and independent classification for accident-prone situations. This finally provides for the visibility these important functions deserve.
Since its creation in 2011 the Pre-Crash-Matrix (PCM) offers the possibility to observe the pre-crash phase until five seconds before crash for a wide range of accidents. Currently the PCM contains more than 8.000 reconstructed accidents out of the GIDAS (German In-Depth Accident Study) database and is enlarged continuously by more than 1.000 cases per year. Hence, a detailed investigation of active safety systems in real accident situations has been made feasible. The PCM contains all relevant data in database format to simulate the pre-crash phase until the first collision of the accident for a maximum of two participants. This includes the definition of the participants and their characteristics, the dynamic behavior of the participants as time-dependent course for five seconds before crash as well as the geometry of the traffic infrastructure. The digital sketch of the accident and information from GIDAS as well as from supplementary databases represent the main input for the simulation of the pre-crash phase of an accident with the VUFO simulation model VAST (Vufo Accident Simulation Tool). This simulation in turn embodies the foundation of the PCM. The PCM underlies continual improvements and enhancements in consultation with its users. In addition to collisions of cars with other cars, pedestrians, bicycles and motorcycles the PCM now also covers car to object and car to truck collisions. The paper illustrates car to truck collisions as a showcase and explains perspectives for further developments. In 2016 a more detailed definition of the contour of the vehicle was added. Furthermore, the geometrical surroundings of the accident site will be provided in a new structure with a higher level of detail. Thus, a precise classification of road marks and objects is possible to further improve the support of developing and evaluating ADAS. This paper gives an overview about the latest developments of the PCM with its innovations and provides an outlook to upcoming enhancements. Besides potential areas of application for the development of ADAS are shown.
For more than a decade, ADAC accident researchers have analysed road accidents with severe injuries, recording some 20,000 accidents. An important task in accident research is to determine the causative factors of road accidents. Apart from vehicle engineering and human factors, accident research also focuses on infrastructural and environmental aspects. To find out what accident scenarios are the most common in ADAC accident research and what driver assistance systems can prevent them, our first task was to conduct a detailed accident analysis. Using CarMaker, we performed a realistic simulation of accident scenarios, including crashes, with varying parameters. To begin with, we made an initial selection of driver assistance systems in order to determine those with the greatest accident prevention potential. One important finding of this study is that the safety potential of the individual driver assistance systems can actually be examined. It also turned out that active safety offers even much more potential for development and innovation than passive safety. At the same time, testing becomes more demanding, too, as new systems keep entering the market, many of them differing in functional details. ADAC will continue to test all driver assistance systems as realistically as possible so as to be able to provide advice to car buyers. Therefore, it will be essential to develop and improve test conditions and criteria.
At IAM RoadSmart we share the excitement about autonomous cars " who wouldn't! However over half of the drivers we polled supported concentrating on making drivers safer " among IAM RoadSmart members it was 70%. Driverless cars are still years away but delivering safer drivers can help reduce death and injury from tomorrow. Governments, academics and car makers need to work hard to convince sceptical British and American drivers that autonomous cars can deliver the benefits promised such as a 90% plus reduction in road deaths.
The advent of active safety systems calls for the development of appropriate testing methods. These methods aim to assess the effectivity of active safety systems based on criteria such as their capability to avoid accidents or lower impact speeds and thus mitigate the injury severity. For prospective effectivity studies, simulation becomes an important tool that needs valid models not only to simulate driving dynamics and safety systems, but also to resolve the collision mechanics. This paper presents an impact model which is based on solving momentum conservation equations and uses it in an effectivity study of a generic collision mitigation system in reconstructed real accidents at junctions. The model assumes an infinitely short crash duration and computes output parameters such as post-crash velocities, delta-v, force directions, etc. and is applicable for all impact collision configurations such as oblique, excentric collisions. Requiring only very little computational effort, the model is especially useful for effectivity studies where large numbers of simulations are necessary. Validation of the model is done by comparison with results from the widely used reconstruction software PC-Crash. Vehicles involved in the accidents are virtually equipped with a collision mitigation system for junctions using the software X-RATE, and the simulations (referred to as system simulations) are started sufficiently early before the collision occurred. In order to assess the effectivity, the real accident (referred to as baseline) is compared with the system simulations by computing the reduction of the impact speeds and delta-v.
The incidence of side impacts was investigated from GIDAS data. Both vehicle-fixed object and vehicle-vehicle collisions were analysed as these are enclosed within the consumer testing program. Vehicle-fixed object collisions were stratified according to ESC availability. Results indicated that vehicles equipped with ESC rarely have pure-lateral impacts. An increase in oblique collisions was seen for the vehicles with ESC whereby most vehicle were driving in left curves. The analysis of vehicle-vehicle collisions developed injury risk curves were developed at the AIS3+ injury severity for the vehicle-vehicle side impacts. Results suggested that greatest injury risk occurred when a Pre Euro NCAP vehicle was struck by a Post Euro-NCAP vehicle. The remaining curves did not show different behaviour, indicating that stiffness increased have been equally combated. This was attributable to the few Post Euro-NCAP vehicles that had a deployed curtain airbag available in the sample. The integration of Euro NCAP testing has shown to improve vehicle crashworthiness for pole collisions, as those vehicles with ESC rarely incur lateral impacts.
Injury probability functions for pedestrians and bicyclists based on real-world accident data
(2017)
The paper is focusing on the modelling of injury severity probabilities, often called as Injury Risk Functions (IRF). These are mathematical functions describing the probability for a defined population and for possible explanatory factors (variables) to sustain a certain injury severity. Injury risk functions are becoming more and more important as basis for the assessment of automotive safety systems. They contribute to the understanding of injury mechanisms, (prospective) evaluation of safety systems and definition of protection criteria or are used within regulation and/or consumer ratings. In all cases, knowledge about the correlation between mechanical behavior and injury severity is needed. IRFs are often based on biomechanical data. This paper is focusing on the derivation of injury probability models from real world accident data of the GIDAS database (German In-depth Accident Study). In contrast to most academic terms there is no explicit term definition or definition of creation processes existing for injury probability models based on empirical data. Different approaches are existing for such kind of models in the field of accident research. There is a need for harmonization in terms of the used methods and data as well as the handling with the existing challenges. These are preparation of the dataset, model assumptions, censored/unknown data, evaluation of model accuracy, definition of dependent and independent variable, and others. In the presented study, several empirical, statistical and phenomenological approaches were analyzed regarding their advantages and disadvantages and also their applicability. Furthermore, the identification of appropriate prediction parameters for the injury severity of pedestrians has been considered. Due to its main effect on injuries of pedestrians and bicyclists, the importance of the secondary impact has also been analyzed. Finally, the model accuracy, evaluated by several criteria, is the rating factor that gives the quality and reliability for application of the resulting models. After the investigation and evaluation of statistical approaches one method was chosen and appropriate prediction variables were examined. Finally, all findings were summarized and injury risk functions for pedestrians in real world accidents were created. Additionally, the paper gives instructions for the interpretation and usage of such functions. The presented results include IRFs for several injury severity levels and age groups. The presented models are based on a high amount of real world accidents and describe very well the injury severity probability of pedestrians and bicyclists in frontal collisions with current vehicles. The functions can serve as basis for the evaluation of effectiveness of systems like Pedestrian-AEB or Bicycle-AEB.
Bus or heavy vehicle passenger accidents are rare events, compared with car accidents, but sometimes leads to a large number of victims especially in rollover crash scenarios. Two accidents occurred in Portugal in 2007 and 2013 in which 28 people died and more than 50 are injured, shown the importance of the investigation of such accidents. For the investigation of these accidents multidisciplinary teams are constituted with engineers and police officers. All the factors involved are taken into consideration including road design, traffic signs, maintenance and hardware, human factors, and vehicle factors. In this work a methodology to an accurate collection of the data is proposed. From the information collected the accident is reconstructed using the PC-CrashTM software. From this all the contribution factors are determined and recommendations to mitigate these crashes are listed. These two accidents are rollover accidents and the analysis of the injuries and its correlation with the use of retention systems is very important. From the medical data and with the dynamics of the accident determined simulations of the occupants with biomechanical models are carried out in order to evaluate the effect of the retention systems in the injuries. This analysis is based on injury criteria (such as Abbreviated Injury Score (AIS) or Injury Severity Scale (ISS)). With this it is possible to determine if the seat belt was worn or not.
In most of developed countries, the progress made in passive safety during the last three decades allowed to drastically reduce the number of killed and severely injured especially for occupants of passenger cars. This reduction is mainly observed for frontal impacts for which the AIS3+ injuries has been reduced about 52% for drivers and 38% for front passengers. The stiffening of the cars' structure coupled with the generalization of airbags and the improvement of the seatbelt restraint (load limiter, pretension, etc.) allowed to protect vital body regions such as head, neck and thorax. However, the abdomen did not take advantage with so much success of this progress. The objective of this study is to draw up an inventory on the abdominal injuries of the belted car occupants involved in frontal impact, to present adapted counter-measures and to assess their potential effectiveness. In the first part the stakes corresponding to the abdominal injuries will be defined according to types of impact, seat location, occupants' age and type of injured organs. Then, we shall focus on the abdominal injury risk curves for adults involved in frontal impact and on the comparisons of the average risks according to the seat location. In the second part we will list counter-measures and we shall calculate their effectiveness. The method of case control will be used in order to estimate odds ratio, comparing two samples, given by occupants having or not having the studied safety system. For this study, two type of data sources are used: national road injured accident census and retrospective in-depth accident data collection. Abdominal injuries are mainly observed in frontal impact (52%). Fatal or severe abdominal occupant- injuries are observed at least in 27% of cases, ranking this body region as the most injured just after the thorax (51%). In spite of a twice lower occupation rate in the back seats compared to the front seats, the number of persons sustaining abdominal injuries at the rear place is higher than in the front place. In recent cars, the risk of having a serious or fatal abdominal injury in a frontal impact is 1.6% for the driver, 3.6% for the front passenger and 6.3% for the rear occupants. The most frequently hurt organs are the small intestine (17%), the spleen (16%) and the liver (13%). The most common countermeasures have a good efficiency in the reduction of the abdominal injuries for the adults: the stiffness of the structure of the seats allows decreasing the abdominal injury risk from 54% (driver) to 60% (front occupant), the seatbelt pretensioners decrease also this risk from 90% (driver) to 83% (front passenger).
This work describes the results of the experimental activity, illustrating the driving behavior observed in different conditions, relating them to the different methods of ADAS intervention and comparing the driver behavior without ADAS. In the present study, driver behavior was studied in road accidents involving elderly pedestrians, with different ADAS HMIs, as a base to develop a driver model in near missing pedestrian accidents. A literature research was conducted with the aim of finding out the main influencing factors, including environment, boundary conditions, configuration of impact, pedestrian and driver information, when pedestrian fatalities occur and an analysis of frequent road accidents was conducted to get more detailed information about the driver- behavior. In order to obtain more detailed information about pedestrian accidents, real road accidents were reconstructed with multibody simulations on PC-Crash and, by the comparison between literature findings and reconstructions, a generic accident scenario was defined. The generic accident scenario was implemented on the full scale dynamic driving simulator in use at the Laboratory for Safety and Traffic Accident Analysis (LaSIS, University of Florence, Italy) in order to analyse the driving behaviors of volunteers, also considering the influence of ADAS devices. Forty-five young volunteers were enrolled for this study, resulting in forty valid tests on different testing scenarios. Two different scenarios consisted in driving with or without ADAS in the vehicle. Different kinds of ADAS, acoustic and optical, with different time of intervention were tested in order to study the different reactions of the driver. The tests showed some interesting differences between driver's behavior when approaching the critical situation. Drivers with ADAS reacted earlier, but more slowly, depending also on the type of alarm, and often with double reaction when braking. In fact, the results of the activity showed that with ADAS intervention the time to collision (TTC) increases, but the reaction time and braking modality change: a) there is a sort of "latency" time between the accelerator pedal release and the brake pressure; b) the brake pressure is initially less intense. So the driver only partially takes advance from the TTC increase. These differences were valued not only qualitatively, but quantitatively as well. This work revealed to be useful to improve the knowledge of drivers" behavior, in order to realize a driver model that can be implemented to help attaining and assessing higher levels of automation through new technology.
From an automotive safety occupant protection standpoint, effective occupant restraint requires a system capable of providing non-injurious occupant ride down of anticipated crash forces. This is not only the case for frontal collisions, where occupant restraint is provided primarily by seatbelts and airbags, but is also critical for other crash modes such as side impacts, rear impacts, rollovers, as well as multiple impact events. In the rear impact crash mode, occupant restraint is provided primarily by the seatbacks and to some extent the seatbelts. Foundationally, therefore, what becomes fundamental to the seatback's role in rear occupant protection is its ability to contain the occupant within the seat, preventing occupant ramping, as well as preventing the seat's, and/or its occupant's, dangerous intrusion into the rear occupant's survival space where contact with rear compartment components and/ or rear seated occupants can present a significant injury risk. An analysis is presented of a series of rear impact sled testing conducted by the authors that evaluates the timing, position and extent of the front seatback's reward displacement toward and into the rear occupant compartment as well as consideration of the front seat occupant' ramping potential and its injury potential relative to the rear compartment. Additionally, three other series of testing are presented which assess various seat designs occupant retention capabilities. Lastly, a matched-pair comparison test series is presented which evaluates occupant motion in rear impact with and without use of a typical vehicle body mounted 3-point seatbelt. Discussion of restraint system performance observed in all the testing is included along with ATD biofidelity and thigh-gap considerations. The data collected and presented includes accelerometer instrumentation and high speed video analysis.
Twenty-eight percent of traffic accidents in Japan are rear-end collisions, and of these, 13% are multiple collisions (three or more vehicles and/or roadside objects). A post-crash braking system enables the driver to stop the vehicle in a short distance after a rear-end collision to prevent secondary collisions. In this study, the effectiveness of a post-crash braking system was examined using a drive recorder database. In 64% of rear-end collisions, the driver's braking was interrupted after the collision. The stopping distance was estimated with time data from the drive recorder. We predict that the brake assist would be effective in preventing secondary collisions in 21% of cases.
This study investigates the protection offered by passive head-restraints with different stiffness and energy dissipation properties. For this purpose, computational multi-body models of a generic car seat and a biofidelic 50thpercentile male human for rear impact are used to study different seat designs and passive head-restraints. The validated seat-occupant model is also used in the design of two different car-seat models which are shown to effectively mitigate whiplash by utilising a crash-energy distribution technique. Five different passive head-restraints with varying stiffness (low-medium-high) and energy dissipation percentages (low-high) are successively attached to four different car-seat models. The simulation results indicate that the protection offered by head restraints is strongly dependent on the seat design. It has also been shown that the stiffness of the passive head-restraint has much more influence on whiplash-risk in comparison to its energy dissipation capacity.
Test and assessment procedures for passive pedestrian protection based on developments by the European Enhanced Vehicle-safety Committee (EEVC) have been introduced in world-wide regulations and consumer test programmes, with considerable harmonization between these programmes. Nevertheless, latest accident investigations reveal a stagnation of pedestrian fatality numbers on European roads running the risk of not meeting the European Union- goal of halving the number of road fatalities by the year 2020. The branch of external road user safety within the EC-funded research project SENIORS under the HORIZON 2020 framework programme focuses on investigating the benefit of modifications to pedestrian test and assessment procedures and their impactors for vulnerable road users with focus on the elderly. Injury patterns of pedestrians and cyclists derived from the German In-Depth Accident Study (GIDAS) show a trend of AIS 2+ and AIS 3+ injuries getting more relevant for the thorax region in crashes with newer cars (Wisch et al., 2017), while maintaining the relevance for head and lower extremities. Several crash databases from Europe such as GIDAS and the Swedish Traffic Accident Data Acquisition (STRADA) also show that head, thorax and lower extremities are the key affected body regions not only for the average population but in particular for the elderly. Therefore, the SENIORS project is focusing on an improvement of currently available impactors and procedures in terms of biofidelity and injury assessment ability towards a better protection of the affected body regions, incorporating previous results from FP 6 project APROSYS and subsequent studies carried out by BASt. The paper describes the overall methodology to develop revised FE impactor models. Matched human body model and impactor simulations against generic test rigs provide transfer functions that will be used for the derivation of impactor criteria from human injury risk functions for the affected body regions. In a later step, the refined impactors will be validated by simulations against actual vehicle front-ends. Prototyping and adaptation of test and assessment procedures as well as an impact assessment will conclude the work of the project at the final stage. The work will contribute to an improved protection of vulnerable road users focusing on the elderly. The use of advanced human body models to develop applicable assessment criteria for the revised impactors is intended to cope with the paucity of actual biomechanical data focusing on elderly pedestrians. In order to achieve optimized results in the future, the improved test methods need to be implemented within an integrated approach, combining active with passive safety measures. In order to address the developments in road accidents and injury patterns of vulnerable road users, established test and assessment procedures need to be continuously verified and, where needed, to be revised. The demographic change as well as changes in the vehicle fleet, leading to a variation of accident scenarios, injury frequencies and injury patterns of vulnerable road users are addressed by the work provided by the SENIORS project, introducing updated impactors for pedestrian test and assessment procedures.
Supported by field accident data and monitoring results of European Regulation (EC) No. 78/2009, recent plans of the European Commission regarding a way forward to improve passive safety of vulnerable road users include, amongst other things, an extension of the head test area. The inclusion of passive cyclist safety is also being considered by Euro NCAP. Although passenger car to cyclist collisions are often severe and have a significant share within the accident statistics, cyclists are neither considered sufficiently in the legislative nor in the consumer ratings tests. Therefore, a test procedure to assess the protection potential of vehicle fronts in a collision with cyclists has been developed within a current research project. For this purpose, the existing pedestrian head impact test procedures were modified in order to include boundary conditions relevant for cyclists as the second big group of vulnerable road users. Based on an in-depth analysis of passenger car to cyclist accidents in Germany the three most representative accident constellations have been initially defined. The development of the test procedure itself was based on corresponding simulations with representative vehicle and bicycle models. In addition to different cyclist heights, reaching from a 6-year-old child to a 95%-male, also four pedal positions were considered. By reconstruction of a real accident the defined simulation parameters could be validated in advance. The conducted accident kinematics analysis shows for a large portion of the constellations an increased head impact area, which can reach beyond the roof leading edge, as well as high average values for head impact velocity and angle. Based on the simulation data obtained for the different vehicle models, cyclist-specific test parameters for impactor tests have been derived, which have been further examined in the course of head and leg impact tests. In order to study the cyclist accident kinematics under real test conditions, different full scale tests with a Polar-II dummy positioned on a bicycle have been conducted. Overall, the tests showed a good correlation with the simulations and support the defined boundary test conditions. Typical accident scenarios and simulations reveal higher head impact locations, angles and velocities. An extended head impact area with modified test parameters will contribute to an improved protection of vulnerable road users including cyclists. However, due to significantly differing impact kinematics and postures between the lower extremities of pedestrians and cyclists, these injuries cannot be addressed by the means of current test tools such as the flexible pedestrian legform impactor FlexPLI. Based on the findings obtained within the project as well as the existing pedestrian protection requirements a cyclist protection test procedure for use in legislation and consumer test programmes has been developed, whose requirements have been transferred into a corresponding test specification. This specification provides common head test boundary conditions for pedestrians and cyclists, whereby the existing requirements are modified and two parallel test procedures are avoided.
Neue Herausforderungen an die Unfallforschung durch Fahrerassistenz und automatisiertes Fahren
(2019)
Unfallrekonstruktion hat die Ableitung von Maßnahmen zur Minimierung der Unfallfolgen ermöglicht, vor allem durch Verbesserungen bei passiven Sicherheitseinrichtungen, aber auch durch die Verbesserung der Rettungskette, beispielsweise eCall. Heute können aktive Sicherheitssysteme die Unfallfolgen bereits vor der eigentlichen Kollision reduzieren oder durch Umfeldwahrnehmung und mittels Eingriff in die Fahrzeugsteuerung gegebenenfalls sogar vollständig verhindern. Funktionen, die aktiv in die Fahrzeugsteuerung eingreifen, lassen sich nach ihrer Wirkweise unterscheiden: zum einen handelt es sich um kontinuierlich automatisierende Funktionen, die meist länger aktiv bleiben (zum Beispiel ACC). Zum anderen um Funktionen, die in kritischen Fahrsituationen temporär in die Fahrzeugsteuerung eingreifen. Aufgezeigt wird, welche Konsequenzen und Risiken in Bezug auf diese Systeme sowie für bestimmte (zum Beispiel kritikale) Fahrsituationen anzunehmen sind. Zur Bewertung von aktiven Reglern, die in kritischen Fahrsituationen eingreifen, sind Unfalldaten nur noch eingeschränkt tauglich. Ähnliches gilt für die Bewertung von Ereignissen/ Zuständen im Rahmen kontinuierlicher Fahrzeugsteuerung, vor allem, wenn diese weiter vorausliegen. Wirkzusammenhänge automatisierter Fahrfunktionen müssen jedoch - gerade für den Mischverkehr mit konventionell gesteuerten Fahrzeugen - identifiziert werden. Dafür wird eine Szenariendatenbank mit relevanten Verkehrssituationen benötigt, in die Daten aus Naturalistic Driving Studies (NDS), aus Fahrversuchen oder Versuchen im Fahrsimulator eingehen können. Die zunehmende Durchdringung der Fahrzeugflotte mit kontinuierlich automatisierten Fahrfunktionen lässt eine Abnahme kritischer Fahrsituationen und eine Reduktion der Zahl der Verkehrsopfer erwarten. Allerdings verbleibt eine Restzahl an systemimmanenten Unfällen, die als unvermeidbar gelten müssen.