Ms. Jayne Hoskins
Senior Engineer
Jaguar Cars Ltd.
Abbey Road
Whitley, Coventry CV3 4LF
England

Dear Ms. Hoskins:

This is in response to several questions asked by Jaguar Cars Ltd. (Jaguar) regarding test procedures under the head impact protection provisions contained in Standard No. 201, Occupant protection in interior impact.

In your facsimile transmission, you ask if the National Highway Traffic Safety Administration (NHTSA) would consider compliance in all the specified target locations as acceptable evidence of meeting the requirements of the Standard. You also ask if the head protection provisions are still relevant in those areas where head protection is provided by side airbags. Finally, you ask about the status of any rulemaking regarding airbag systems that provide such head protection.

In a subsequent electronic mail message, you describe a concern you have regarding a seat belt anchorage d-ring which prevents the free motion headform (FMH) from impacting on target point BP-3. You asked if you should: a) increase the size of the target zone, b) move the headform around to hit the target with the side of the headform, or c) slide/rotate the d-ring out of the way.

In regard to your initial question, the head protection requirements of Standard 201 require manufacturers to meet performance requirements only at those target points that are located using the procedures found in S10 of 49 CFR 571.201. The original proposal for the head protection requirements envisioned performance requirements for zones. This was modified in the final rule to specify individual targets. However, you should be aware that, whatever means Jaguar may use in fulfilling its responsibility to certify its vehicles, that NHTSA will follow the test procedures outlined in Standard 201 in performing its own compliance tests and reserve the right to test all possible targets at all possible target locations.

You also ask whether the agency is contemplating any changes to Standard 201 to accommodate dynamic head protection systems. These systems, which use air bags that deploy from the roof rail and other areas to provide head protection in side impacts, are the subject of a notice of proposed rulemaking (NPRM) issued by the agency on August 19, 1997 and published in the Federal Register on August 26, 1997 (62 FR 45202). In that document, NHTSA proposed that manufacturers be provided with several options for demonstrating compliance with the head protection requirements of Standard No. 201. Under two of the proposed optional tests, target points over an undeployed system are impacted at reduced speeds and the deployed system is tested through impacts at higher speeds or through a full scale crash test involving an 18 mph side impact into a rigid pole.

In an electronic mail message forwarded after your original facsimile transmission, you ask about the appropriate procedure to be followed in the event that seat belt attachment hardware, specifically a d-ring, is located within a target zone and interferes with contact between the forehead impact zone of the FMH and the target point. S10.2(b) specifies that if a seat belt anchorage is on the B-pillar, target BP2 is located at any point on that anchorage. If the target in question is BP2, S8.7 provides that where an anchorage is adjustable, tests are to be conducted with the anchorage adjusted to a point midway between the two adjustment positions. If the target in question is not BP2, the anchorage may be moved within its range of adjustment so that the d-ring does not interfere with contact between the FMH and the target point. If the location of the d-ring still prevents contact between the forehead impact zone and the target area, S10(b) provides a procedure for relocating targets within a 25 millimeter sphere centered at the original target:

(b) Except as specified in S10(c), if there is no combination of horizontal and vertical angles specified in S8.13.4 at which the forehead impact zone of the free motion headform can contact one of the targets located using the procedures in S10.1 through S10.13, the center of that target is moved to any location within a sphere with a radius of 25 mm, centered on the center of the original target and measured along the vehicle interior, which the forehead impact zone can contact at one or more combination of angles.

If it is still not possible for the forehead impact zone to make contact within the sphere described in S10(b), S10© provides that the sphere may be expanded in 25 mm increments until contact can be made.

I hope that this is responsive to your inquiry. If you have any questions, please contact Otto Matheke of this office at (202) 366-5263 or by electronic mail at omatheke@nhtsa.dot.gov.

Sincerely,
John Womack
Acting Chief Counsel
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