The potential benefit of fitting AEB systems to cars in Europe for pedestrian protection has been estimated and the results interpreted to indicate the upper limit of cost for a system to allow it to be cost effective.
Compatibility is now generally recognized as the next big step forwards for car occupant secondary safety. The work performed to date has focused on the structural performance of vehicles, with the aim of providing a safe environment for the protection of the occupants in which intelligent restraint systems of the future could operate. This paper outlines the present understanding of compatibility for frontal impact collisions and reports the current state of development of three possible test procedures to address the fundamental issues, namely structural interaction, frontal sti ness matching and passenger compartment strength. Recent advances in the development of a deformable barrier face for the full-width test to assess structural interaction, using high-resolution load cell wall measurements, are described. Analysis of the load cell wall data collected in EuroNCAP tests, to address the frontal sti ness problem, is reported together with initial work to investigate the repeatability of the passenger compartment strength test. In addition, for some of these tests, possible performance criteria are suggested. This research is being carried out in co-operation with the European Enhanced Vehicle-safety Committee and the International Harmonization of Research Activities Working Groups and is funded by the Department for Transport.
Objective: Autonomous emergency braking (AEB) systems fitted to cars for pedestrians have been predicted to offer substantial benefit. On this basis, consumer rating programs-for example, the European New Car Assessment Programme (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 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 AEB and passive safety components. The method should include weighting procedures to ensure that it represents injury patterns from accident data and replicates an independently estimated benefit of AEB.Methods: A methodology has been developed to calculate the expected societal cost of pedestrian injuries, assuming that 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, the cost for the assessed car is normalized by comparing it to the cost calculated for a reference car.The speed reductions measured in AEB tests are used to determine the speed at which each pedestrian in the target population will be impacted. Injury probabilities for each impact are then calculated using the results from Euro NCAP pedestrian impactor tests and injury risk curves. These injury probabilities are 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 Great Britain and an independently estimated AEB benefit. German and Great Britain versions of the methodology are available. The methodology was used to assess cars with good, average, and poor Euro NCAP pedestrian ratings, in combination with a current AEB system. The fitment of a hypothetical A-pillar airbag was also investigated.Results: 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. Because the assessment was influenced strongly by the level of head protection offered in the scuttle and windscreen area, a hypothetical A-pillar airbag showed high potential to reduce overall casualty cost.Conclusions: A benefit-based methodology for assessment of integrated pedestrian protection systems with AEB has been developed and tested. It uses input from AEB tests and Euro NCAP passive safety tests to give an integrated assessment of the system performance, which includes consideration of effects such as the change in head impact loca...
A major component of the EU Fifth Framework Programme sponsored project "Improvement of Vehicle Crash Compatibility Through the Development of CrashTest Procedures" (VC-Compat) focused on car-to-car frontal crash compatibility. The work program was composed of four main activities, a structural survey, cost-benefit analyses, crash testing, and supporting modeling work. All these activities focused on the development of two candidate test procedures, namely the full-width deformable barrier (FWDB) and progressive deformable barrier (PDB), which are capable of assessing a car's structural interaction potential. These tests have different approaches; the FWDB assessment is based on load cell wall force measurements, whereas the PDB assessment is based on deformation measurements. This work supports the activities of the European Enhanced Vehicle Safety Committee working group on frontal impact and compatibility, which has the task to propose draft test procedures to assess a vehicle's crash compatibility in 2007.
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.
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