Technical Feasibility 03/1/15 Technical Feasibility 1. Introduction In view of the large percentage of pedestrian fatalities and injuries in the total road accident casualties, the protection of pedestrians has become a critical issue as apparent from the European NCAP enforcement, drafting of pedestrian protection regulations, and the ongoing international movement to harmonize the pedestrian-related regulations of various regions. The initiation and harmonization of pedestrian-related regulations are being discussed primarily on the basis EEVC's proposed draft. The EEVC draft, however, leaves much room for discussion over the biofidelic adequacy of its proposed requirements and test equipment. Furthermore, the EEVC draft poses doubts over its technical feasibility regarding the allowance of a sufficient technological and design freedom to vehicles. Throughout the history of motor vehicles, a diversity of technical regulations and requirements have been developed in order to provide people with comfortable, convenient and safe transit. Technical requirements exist in the form not only of national regulations but also of private standards established by each vehicle manufacturer. Vehicles must conform with these technical regulations and standards; at the same time, vehicles must offer satisfactory interior and exterior designs to the customers in order to be accepted as marketable products. Pedestrian protection technologies are not exceptions in that they must coexist with the other requirements and designs used in the marketable vehicle. Therefore, if a regulation is incapable of assuring such coexistence, this regulation cannot be considered to have "technical feasibility".
1. Coexistence with the other requirements 1-1. Analysis of the Proposed Regulations(Japan’s proposal or NA) The technical feasibility of the draft pedestrian protection regulations proposed in Europe and Japan was examined. Assuming coexistence with other functions of the vehicle and an impact speed of 35 km/h (also 32 km/h), it has been found that in the vehicle front structure there are several areas difficult to be HIC value lower than 1000, as shown below. 1 2 3 4 5 6 ※ Impactor Weight 3.5kg Even with this structure it is impossible to meet the EEVC requirements. 70mm Usually car manufacture have 20% margin,therefor the target of HIC value should be lower than around 800. 1-2. Examination of Pillar Areas The full-scale tests conducted by Mr. Mizuno, Mr. Matsui and other experts have indicated that the HIC values in the areas around the pillars exceed 3000. Since the pillars and their supporting areas serve as the structural components for creating survival spaces for the occupants in rollover accidents and offset frontal collisions, it is difficult to reduce the rigidity of the pillars and their supporting areas. It is also difficult to introduced a 60mm- thick padding into each pillar area to yield a collapsible stroke, due to the impairment of the driver's effective field of vision. ESV 94-S7-W-14“Concept of hood design for possible reduction in pedestrian head injury” Vol. 30 No.4 October 1999 in JSEA paper”Relation between head and impact location in car-pedestrian impact”
2. Special Vehicle Types Besides the aforementioned issues, the following issues must be considered for special types of vehicles. (1) Sports cars These vehicles pose difficulties in obtained a sufficient stroke for absorbing an impact. A lead time equivalent or longer than the lead time for a full model change will be needed if a new engine, suspensions and other units are to be developed for obtaining a sufficient stroke. (2) SUVs Because these vehicles are expected to have fenders, cowls and other exterior components more durable than those of passenger cars, it is more difficult to develop technologies in which pedestrian protection and other automotive functions will be able to coexist. (3) Full cab-over vehicles To introduce pedestrian protection measures into these vehicles, one approach is to reduce the sizes of the components and rearrange their positions in the engine room. Another approach is to move the outboard panel either forward or upward, which will impair the downward visibility by the driver. Due to the major changes involved, visibility impairment and technical complexity, it will require a long time to introduce the necessary pedestrian protection into these vehicles. (4) Hybrid vehicles As these vehicles must house a large number of components inside the engine room, it is difficult to introduce structural changes into hybrid vehicles. 3. Cases of Impact Speed Exceeding 40 Km/h OICA explained the report (INF GR/PS/5) with regard to the analysis of pedestrian-vehicle accidents where the impact speed exceeds 40 km/h at the 1st INF meeting.