Interpretation ID: 2665y
Program Manager
Via Systems
1328 Cimarron Drive
Santa Ynez, CA 93460
Dear Mr. Palius:
This responds to your letter to Steve Kratzke of my staff, seeking an interpretation of the effects of a procedural provision that appears in the compliance test procedures for Standard No. 208, Occupant Crash Protection, but not in the standard itself. Specifically, you asked whether crash testing under Standard No. 208 must be conducted only with a tow road 500 feet in length. I am pleased to have this opportunity to explain our laws and regulations for you.
Before addressing your specific question, it might be helpful to begin with some general background information. Each of this agency's safety standards specifies test conditions and procedures that this agency will use to evaluate the performance of the vehicle or equipment being tested for compliance with the particular safety standard. NHTSA precisely follows each of the specified test procedures and conditions when conducting its compliance testing.
In addition to the test conditions and procedures set forth in the safety standards themselves, the agency has provided guidelines to the test facilities that the agency enters into contracts with to conduct compliance tests for the agency. These guidelines are called compliance test procedures. The compliance test procedures are intended to provide a standardized testing and data recording format among the various contractors that perform testing on behalf of the agency, so that the test results will reflect the performance characteristics of the product being tested, not differences between the various testing facilities.
The compliance test procedures must, of course, not be inconsistent with the procedures and conditions that are set forth in the relevant safety standard. However, the compliance test procedures do, on occasion, specify procedures and conditions that go beyond what is set forth in the relevant standard. These more detailed test procedures and conditions are requirements only for the contractor test facility in conducting tests on behalf of the agency.
With that background, I will now address your specific question. A manufacturer must certify that its vehicles will comply with the requirements of Standard No. 208 when they are tested in accordance with the procedures set forth in various sections of the standard, including S5, S8, S10, and S11. These sections specify that the vehicle shall be traveling longitudinally forward at any speed up to and including 30 miles per hour (mph). However, these sections do not specify any particular length for a tow road for crash testing. Accordingly, the manufacturer's certification of compliance with Standard No. 208 may be based on tests using a tow road of any length, provided that all applicable conditions in Standard No. 208 are satisfied.
You correctly noted that NHTSA's compliance test procedures currently specify that the tow road should be at least 500 feet in length. This length was chosen for agency compliance testing to ensure the test dummies' positioning would not be affected by the acceleration of the vehicle and that the test dummies' positioning would be stabilized before impact. Tow roads of this length also allow sufficient room to abort the test if needed. Please note that, although a manufacturer is not required to use a 500-foot tow road in its certification testing, a shorter tow road that affected the dummies' positioning might not provide an adequate basis for certifying that the tested vehicle complies with the occupant protection requirements of Standard No. 208.
Please feel free to contact Mr. Kratzke at this address or by telephone at (202) 366-2992 if you have any further questions on this subject.
Sincerely,
Paul Jackson Rice Chief Counsel
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