Interpretation ID: aiam1986
Commander
Engineering Section
Department of California Highway Patrol
P. O. Box 898
Sacramento
CA 95804;
Dear Mr. Heath: This is in response to your letter dated April 2, 1975, in which yo ask several questions regarding test procedures for Federal Motor Vehicle Safety Standard No. 218, *Motorcycle Helmets*.; We are not aware of any inconsistency between Standard No. 218 and th compliance procedures that our Office of Standards Enforcement has developed in connection with it. If there were any, of course, the standard would be controlling. The standard specifies a drop height, and a 'guided free fall' from that height. We consider 'free fall' to be an objective and unambiguous physical term, meaning a movement in response to the force of gravity unimpeded by any resistance except air resistance. The requirement the equipment must be capable of meeting, therefore, refers to a fall in which the guiding method imparts no significant resistance, *i.e.*, it does not affect the results. Although in practice a perfectly frictionless guided fall may be unachievable, a manufacturer must ensure that his product would meet the requirement no matter how small the friction. An analogy is the fixed collision barrier defined in S 49 CFR 571.3, which requires a vehicle to meet a barrier crash test requirement using a barrier that absorbs no significant part of the vehicle's energy. Helmet manufacturers must assume, therefore, that the government will test their products using test fixtures that impart as little friction to the fall as possible. We therefore consider the issue of what systems were 'in general use at the time ANS Z90.1 and FMVSS 218 were written' to be irrelevant to the question of compliance.; This discussion should answer your first two questions. We do no accord any legal status to 'old' test procedures as opposed to 'new' ones. With regard to the question about correlation studies, we have not conducted any and I know of no plans to do so. Finally, Standard 218 presently covers only size C helmets because drawings and headforms for the other sizes are not yet available. Therefore, no formal compliance testing can be done on other sizes of helmets. We hope soon to publish drawings and make available models of size A, B and D headforms, at which time a date will be set for extending Standard 218 to these other sizes. Your continuing interest in motorcycle safety is greatly appreciated.; Sincerely, Frank Berndt, Acting Chief Counsel