Interpretation ID: aiam3349
1545 University Avenue
Palo Alto
CA 94301;
Dear Mr. Blythe: This responds to your recent letter asking questions concerning th test procedures of Safety Standard No. 216, *Roof Crush Resistance* (49 CFR 571.216). Specifically, you are concerned with the proper applications of the test block forces specified in paragraphs S6.3 and S6.2(d) of the standard.; Your first question asks whether paragraph S6.3 allows the force on th test block to be applied 'essentially opposite the initial contact point of the roof to the block.' Paragraph S6.3 specifies that the force required by the standard shall be applied in a downward direction to the lower surface of the test device. Figure 1 of the standard illustrates this procedure and indicates that the force is to be centrally applied to the loading block. This procedure will be followed during tests by the agency to determine the compliance of particular passenger cars with Safety Standard No. 216. Therefore, we would not recommend that you apply the force opposite the initial contact point of the test block with the roof.; Paragraph S6.2(d) of the standard specifies that the initial contac point (with the roof) is on the longitudinal centerline of the lower surface of the test device and 10 inches from the forwardmost point of the centerline. Your second question asks whether this 10-inch dimension should be maintained if this places the leading edge of the test device behind the leading edge of the roof and the A-pillars. You state that this would occur with certain roof configurations which tend to be high in the center (i.e., in which the leading edge of the roof is not the highest point of the roof). A manufacturer should adhere to the 10-inch dimension even if this means the leading edge of the test device will not be forward of the A-pillar and the roof's forward edge. The test procedures specified are standardized procedures which the agency applies to all passenger cars regardless of roof configuration. Thus, the agency would maintain the 10-inch dimension even when testing a roof with a higher center than its leading edge.; I would like to point out, however, that the test procedures specifie in the safety standards only document how the agency will conduct its compliance tests. Manufacturers are not required to test vehicles according to the procedures specified. A manufacturer's responsibility is to exercise due care to ascertain that its vehicles are in fact in compliance with the standards (15 U.S.C. 1397). If you are convinced that the procedures mentioned in your letter would accurately test the compliance of a particular vehicle with Safety Standard No. 216, you are certainly permitted to use those procedures. It is up to the manufacturer, however, to determine whether it has in fact exercised due care to determine compliance.; I hope this has been responsive to your inquiry. Sincerely, Frank Berndt, Chief Counsel