Interpretation ID: aiam0048
Assistant Director of Research and Development
Renault
Billancourt - Seine
Paris
France;
Dear Mr. de Castelet: Thank you for your letter of December 1, 1967, concerning tests make o the Renault 10 model for compliance with Federal Motor Vehicle Safety Standard No. 203.; We recognize the validity of a system which takes advantage of th energy absorbing characteristics of the surrounding vehicle structure as on alternative to the more conventional approach of employing an energy absorbing column and/or wheel. As you mentioned, SAE J944 was not written with that type of energy absorbing system in mind. The structure which you intend to employ to provide the energy absorbing requirements specified in Federal Motor Vehicle Safety Standard No. 203 might in reality first be severely stressed and deformed in a crash situation. Therefor any laboratory test used to evaluate such a system should recognize this detrimental influence. In the event that you would wish to submit a proposed alternative test procedure which incorporates a barrier test as specified in Standard No. 204 prior to testing for compliance with Standard No. 203, we would be pleased to consider such a request.; Your second point concerns the need for a more explicit definition o translational motion. SAE J944 states that the body-block *contracts* the wheel in translational motion. It does not say that this motion must continue after impacting the wheel Your magnetic release mechanism appears to impart approximately translational motion to the body-block at impact and is a satisfactory procedure. The fact that the body-block is free to rotate forward after impact is a simulation of an actual crash restrained in translational motion *after* impact. Since the body motion in an actual crash situation will vary somewhat the Bureau feels that a more explicit definition of translational motion is unnecessary.; The third series of test as described in Report No. 207.397 using rigid test fixture and the free flying body-block are compatible with the SAE J944 test procedure.; Your interest in motor vehicle safety is appreciated. Sincerely, William Haddon, Jr., M.D., Director