Interpretation ID: nht90-4.68

TYPE: Interpretation-NHTSA

DATE: November 30, 1990

FROM: Kotaro Yakushiji -- Vice President, Emissions & Safety Technology, Mazda Research & Development of North America, Inc.

TO: Paul Jackson Rice -- Chief Counsel, NHTSA

TITLE: Re: FMVSS No.216, "Roof Crush Resistance-Passenger Cars"; Request for Interpretation.

ATTACHMT: Attached to letter dated 1-15-91 to Kotaro Yakushiji from Paul Jackson Rice (A37; Std. 216)

TEXT:

Mazda Research and Development of North America, Inc., on behalf of Mazda Motor Corporation of Hiroshima, Japan requests that the Agency render an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 216, "Roof Crush Resistance -Passenger Cars"; considering the conditions herein described.

Specifically, Mazda requests an interpretation of the proper application and orientation of the test block and forces required by paragraphs S6.2 and S6.3 of this standard when testing vehicles equipped, for example, with roof mounted accessories such as luggage racks, sunroof wind deflectors, navigational antennas, etc. Such accessories would neither contribute to or detract from roof strength and would collapse easily and rapidly upon application of the forces required to be sustained. These accesso ries would be easily removed or at least removable for compliance testing purposes. Because these accessories are mounted on the vehicle's roof, each could influence the positioning of the test block as well as distort or render impossible compliance wi th the 5 inch maximum deflection requirement of paragraph S4. Also at issue is how NHTSA would treat such accessories during its compliance testing activities.

Please consider, for instance, the example of the sunroof wind deflector as depicted in Figure 01 of the enclosed attachment. This deflector is constructed of plastic material and is mounted at the wind screen header. For practical purposes this wind de flector is not removable during use but can be removed for testing. Mazda believes that there are three different test conditions which must be considered. These are illustrated in Figure 02 of this same attachment. The specifics of each of these test conditions are as follows.

Condition 1: Test conducted with wind deflector in place. Initial contact point A is at the uppermost point of the deflector. From a practical standpoint, however, contact point B at the vehicle's body is the true contact point.

Condition 2: Test conducted with wind deflector removed. Contact point B established in Condition 1 above is maintained. However, in this instance position B is located at a distance which is greater than (a) 10 inches from the forwardmost point of the longitudinal centerline and, therefore, possibly not in compliance with the positioning requirements of section S6.2(d).

Condition 3: Test conducted with wind deflector removed. Contact point B is identical to conditions 1 and 2. However, the test block is positioned in compliance with section S6.2(d).

Mazda requests the Agency's interpretation of which test condition above, number 1, 2, or 3, is correct and, thus, satisfies the intent of FMVSS No. 216. In the instance that test condition 1 is correct, can the movement of the test block resulting from crushing the wind deflector be deducted from the total test block movement when determining compliance with section S4? Moreover, can the Agency broaden its interpretation in this matter to include other instances involving roof mounted accessories suc h as those listed above?

Mazda thanks the Agency in advance for its kind and prompt consideration of this matter.

Attachment

Figure 1 Sunroof Wind Deflector Figure 2 Possible Test Conditions (Graphics Omitted).