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Annual report 2018
(2019)
With this annual report, BASt is giving the 2018 research year a face. A part of its work is present and in the focus of the public, for example the field test of long trucks, the unique research area duraBASt at the motorway junction Cologne East or the innovative measuring vehicle MESAS for the condition assessment of road surfaces in flowing traffic. A large part of the BASt's work is less effective in attracting public attention but no less important, such as the essential updating of regulations, the testing and approval of products and processes, and the compilation of forecasts and statistics. More than 50 employees report on their research activities and thus give an insight into the tasks of BASt with its core areas of vehicle technology, traffic safety, traffic engineering, road construction as well as bridge and civil engineering. Highlights as well as facts and figures in short and concise form complete the report.
Bicyclists and pedestrians belong to the most endangered groups in urban traffic. The EU-funded collaborative research project PROSPECT (‘PROactive Safety for PEdestrians and CyclisTs´) aims to significantly improve safety of those unprotected traffic participants by expanding the scope of scenarios covered by future active safety systems in passenger cars. Concepts for sensor control systems are built into three prototypes covering emergency interventions such as Autonomous Emergency Braking (AEB) as well as Autonomous Emergency Steering (AES). These systems tackle the well-known challenges of currently available systems including limited field-of-view by sensors, fuzzy path prediction, unreliable intent reaction times and slow reaction times. These highly innovative functions call for extensive validation methodologies based on already established consumer testing procedures. Since these functions are developed towards the prevention of intersection accidents in urban areas, a key aspect of the advanced testing methodology is the valid approximation of naturalistic trajectories using driving robots. Eventually, several simulator studies complemented a user acceptance and benefit analysis to evaluate the expected overall impact of the PROSPECT systems. The results achieved within the PROSPECT project are highly relevant for upcoming test protocols regarding the most critical situations with Vulnerable Road Users (VRU). With introducing the new methods in Euro NCAP (European New Car Assessment Programme) a significant increase in road safety is expected.
At the end of each year, the German Federal Highway Research Institute (BASt) publishes the road safety balance of the closing year. They describe the development of accident and casualty numbers disaggregated by road user types, age groups, type of road and the consequences of the accidents. However, at the time of publishing, these series are only available for the first eight or nine months of the year. To make the balance for the whole year, the last three or four months are forecasted. The objective of this study was to improve the accuracy of these forecasts through structural time-series models that include effects of meteorological conditions. The results show that, compared to the earlier heuristic approach, root mean squared errors are reduced by up to 55% and only two out of the 27 different data series yield a modest rise of prediction errors. With the exception of four data series, prediction accuracies also clearly improve incorporating meteorological data in the analysis. We conclude that our approach provides a valid alternative to provide input to policy makers in Germany.
To assess occupant safety in a crash test, criteria associating the measurements made with a crash test dummy to injury risk are necessary. To enable better protection of elderly car occupants the objective of this study was to develop improved thoracic injury criteria for the THOR average male dummy. The development of these criteria is usually based on matched dummy and Post Mortem Human Surrogate (PMHS) tests by relating the obtained PMHS injuries to dummy measurements. This approach is limited, since only a few tests in relevant loading conditions are available and any new test series requires high efforts to be performed due to their complexity and costs. To overcome these limitations and to extend the dataset for the development of THOR dummy chest injury risk functions a simulation-based approach was applied within the EC funded project SENIORS (Safety Enhanced Innovations For older Road Users - www.seniors-project.eu). Within this study frontal impact sled simulations with an FE model representing a THOR average male dummy and matched simulations with a human body model (HBM) representing an elderly car occupant were carried out. The HBM used for this study was the THUMS TUC with modified rib cage, which was developed in SENIORS. The modifications included material and geometry changes aiming to represent an elderly car occupant. The rib fracture risk was predicted with a deterministic approach whereby a rib was considered broken when the strain exceeded an age-dependent threshold. Furthermore, a probabilistic method was applied to predict the probability of sustaining a certain number of fractured ribs by comparing local strain values to the distribution of cortical rib ultimate strain. By relating the output from the HBM simulations to a multi-point dummy injury criterion, injury risk curves were calculated by statistical methods. The wide range of loading conditions resulted in the desired range of injuries and THOR ATD output. The number of fractured ribs predicted by the HBM based on the deterministic prediction method was between 0 and 15. Furthermore, the probabilistic risk for the number of rib fractures equal or greater than two, three or four was calculated for each load case. The THOR rib deflection criterion Rmax was between 18 and 56 mm, while the PC Score was in the range of 2.5 to 7.2. Based on these outputs new risk curves for the predicted deterministic (AIS2+/3+) and probabilistic injury risk were calculated. The new curves show reasonable shapes and significance that provide trust in their application. The new risk curves are compared to risk curves obtained by traditional methods. The results were found similar to previous injury risk functions based on physical tests, which gives a high level of confidence in the chosen approach. The simulation-based approach of matched ATD model vs. HBM simulation was successfully applied. Rmax curves show a slightly better quality than the injury criterion PC Score.
The "Autonomous driving on the roads of the future: Villa Ladenburg Project" by the Daimler und Benz-Stiftung looks at degrees of automation that will only become technically feasible in the distant future. The treatment of the legal questions in the present chapter therefore draws heavily on the description of the use cases, which begin to provide a concrete basis for evaluating individual issues. Uncertainties in predicting future technical developments can be expected and will have a commensurate impact on the assumptions and conclusions of this chapter. The resulting uncertainty is nevertheless unavoidable if one wants to press ahead with important interrelated issues. This chapter is therefore intended as a contribution to the debate on societal aspects of automated driving from a legal perspective and not as a legalistic evaluation of the subject. The consideration will largely focus on the situation within the context of current German law. The legal views expressed are those of the author and are based on nine years of experience in the field of driver assistance system research. In terms of the underlying conception presented here, the societal dimension of autonomous vehicles addressed in the present project goes well beyond the adjustments to the legal framework currently being called for in Germany. The following will examine the question of "societal acceptance" in the context of the legal questions raised by autonomous vehicles. This line of investigation is not immediately obvious and covers only a segment of the more thoroughgoing focus of the project.
The term driver assistance systems in the chapter title shall be understood to include vehicle automation. This chapter starts with a homogeneous and consistent classification and nomenclature of all kinds of driver assistance systems known and under discussion today (including vehicle automation). It thereby builds upon familiar classification schemes by the German Federal Highway Research Institute (BASt) and the standardization body SAE international. Detailed evaluation of the German legal situation for driver assistance systems and vehicle automation is provided in the following Sect. 2. In Sect. 3, an overview is given on the legal system in the US to reveal aspects relevant for vehicle automation. This is intended as initial information for those not acquainted to the US legal system which has been the first to regulate automation in several federal states. Finally, in Sect. 4, the current rating scheme of the European New Car Assessment Programme (EuroNCAP) is presented in comparison to legal instruments. The model of a consumer protection based approach proves to be a flexible instrument with great advantages in promoting new technologies. Technical vehicle regulations on the other hand rule minimum requirements. Both approaches are needed to achieve maximum vehicle safety.
Effects of time pressure on left-turn decisions of elderly drivers in a fixed-base driving simulator
(2019)
In countries with right lane traffic left-turn maneuvers at intersections are known to be particularly critical for elderly drivers. It has been suggested that the implementation and use of Advanced Driver Assistance Systems (ADAS) might offer a solution to compensate for age-related weaknesses in driving-related skills. In the present paper an experiment is reported which explored the effects of time pressure on the performance of left-turn manoeuvers supported by an ADAS function (time gap assistant). The study was performed in a fixed-base driving simulator with 20 younger (22-37) and 21 elderly drivers (60-84) who were observed when negotiating left-turn manoeuvers on rural roads with and without the assistance function active. Subjects performed the task once under conditions of time pressure once without. Results indicate that both age groups used the assistance function to perform the left-turn manoeuvers with shorter time gaps. Under conditions of time pressure this effect was more pronounced, and the effects of time pressure were stronger for the elderly. However, there were only weak indications for a specific benefit of the assistance function for the elderly.
Airbags are, together with the three-point belt, the most effective passive safety equipment of vehicles. However, literature shows that sound pressure levels of up to 170 dB can occur during airbag deployment. A literature review revealed no systematic experimental data on possible hearing loss by airbag deployment, that also takes any other crash accompanied noise into account, such as deformation and impact noise. Also the rising number of airbags per vehicle resulting in a higher number of deployed airbags in an accident was not addressed with respect to hearing loss. Thus, an extensive test matrix of noise measurements during airbag deployments was conducted including onboard measuring during crashes and static measurements. Dynamic and static experiments with single and multiple airbag deployments were conducted. The results of this study show, that in the analyzed crash constellations the acoustic emission of the collision as well as the car deformation can trigger the stapedius reflex before the airbag deployment. The stapedius reflex protects the inner ear at least partially in case of dangerous sound levels. However, it seems that multiple airbag deployments in a short sequence pose a considerable risk for hearing impairments despite the fully contracted stapedius muscle. Further and in line with Price et al. (2013) it was found that the risk of hearing loss is lower with closed windows. The analysis of patient and accident data showed no link between airbag deployment and hearing loss. This might be caused by low case numbers of reported hearing loss problems up to now. In conclusion the results show that a singular analysis of the sound pressure of airbag deployments without crash accompanied noises is not sufficient as the protective effect of the stapedius reflex is neglected. Still, successive airbag deployments in a short timeframe raise the risk of hearing loss. Further investigation on hearing impairment due to airbag deployment and triggering of the stapedius reflex is needed and the data acquisition of accidents and patients should consider hearing loss aspects.
Traditionally, traffic count statistics in Germany contain the so-called relevant hourly volume, which is defined as the 30th-highest hour of the year when listing the hourly volumes in descending order. When the first edition of the German Highway Capacity Manual (HBS) was prepared in 2001, the Federal Government decided that this 30th hour should be used as the basis for the level of service determination for all Federal freeways and trunk roads. While German freeways are quite well equipped with inductive loop detectors, there are much fewer counts on rural roads and almost no long-term data on urban roads. With the current redraft of the German HBS detailed advice will be given on how to estimate peak-hour demand (all vehicles and heavy vehicle portion), based on the n-th highest hour concept depending on the available traffic counts. As the HBS will be divided into three major parts: freeways, rural roads, and urban roads, three separate chapters for the peak-hour demand estimation will be provided. Whereas for freeways the task consists in finding the comparable site equipped with inductive loop detectors, for urban roads it is a matter of establishing which time periods of the year and weekdays are appropriate for manual short-term counts as estimation of the 30th hour of the year. For all kind of traffic devices the requirements on traffic demand models for level of service calculations are described.
The Netherlands is on the way to change its existing skid resistance measuring method for its highway network from the Dutch RAW 72, a longitudinal force method, to the Sideway Force method. This method is described in the Technical Specification 15901-8 (SKM device) as well as 15901-6 (SCRIM device) and is in use in 9 European countries. The CEN TC 227 WG5 on Surface Characteristics is currently working on combining of these two technical Specifications into a European standard for Sideway-Force (SWF) measurement devices. The idea of this change in the Netherlands was perceived in 2013 and since then a lot of meetings have been held with the different Dutch decision makers as well as with countries which currently operate SWF devices. There was an intensive exchange of knowledge about these devices and their corresponding quality assurance systems, because the Netherlands wanted to incorporate and rely on an existing system of a neighbor country without losing their present level of quality. The Netherlands has therefore decided to incorporate the German SKM approach. The network monitoring with the new system will start in 2017. To ensure the quality of skid resistance measurements and further cooperation in this field, it has been decided to initiate an alliance between BASt and the Dutch road owner Rijkswaterstaat (RWS). This alliance will facilitate an exchange of research activities, calibration of the Dutch systems according to the existing German Standard as well as control measurements with a BASt-device on the Dutch network during the network monitoring. During 2016 also comparative measurements will be performed on a network level with the current Dutch device and with an SKM device to determine a conversion between the two and to be able to define new threshold values.