D. W. Goonewardene, Acting Chief Engineer
Audit & Safety Investigations Section
Federal Office of Road Safety, GPO Box 594
Department of Transport
Canberra ACT 2601
AUSTRALIA

Dear Mr. Goonewardene:

This responds to your letter to Mr. James Hackney of NHTSA, requesting an interpretation of Standard No. 122 Motorcycle brakes. I apologize for the delay in our response. Your questions are answered below.

Some background information on Federal motor vehicle safety laws and regulations may be helpful. Title 49 of the U.S. Code, Chapter 301, Motor Vehicle Safety, authorizes this agency to issue safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA, however, does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, Chapter 301 establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards.

You first asked whether test procedures at S7.6.1, S7.6.3, S7.10.1, and S7.10.2 that specify stops "from 30 mph at 10 to 11 feet per second per second (fpsps) for each stop" mean "an average deceleration for the stop or maintaining the deceleration throughout the test." You also asked, if the procedure is to maintain the deceleration, "what is the allowable time period from the beginning and towards the end of the test that may be excluded from the requirement that the deceleration must be within the specified range or is the approach in S7.6.2 (which requires attaining the required deceleration as quickly as possible and maintaining this deceleration for at least 3/4 of the stopping distance) used?"

We interpret the specification that stops be made "from 30 mph at 10 to 11 feet per second per second (fpsps) for each stop" as referring to maintaining the deceleration within that range throughout the stop, i.e., not as an average. The approach in S7.6.2, which is for higher speed/higher deceleration stops, does not apply to these other sections. As a practical matter, of course, there is a momentary period of time needed at the beginning of the stops to attain the specified deceleration, and possibly a momentary period at the very end of the stops that will be outside the specified range.

You also asked, "if some variation from the specified deceleration occurs, are there any conditions placed on when the maximum pedal/lever forces should be measured (e.g., only when the deceleration is within the specified limits)?" As indicated above, the specified deceleration should be maintained throughout each stop. We would look at the entire stop to determine maximum pedal/lever forces.

I am enclosing for your information a copy our Laboratory Test Procedure for Standard No. 122, prepared by our Office of Vehicle Safety Compliance. The purpose and application of the procedure is explained at the beginning of the document.

I hope this information is helpful. If you have any further legal questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992. Our FAX number is (202) 366- 3820. If you have technical questions, including ones about the enclosed Laboratory Test Procedure, please contact Luke Loy of our Office of Vehicle Safety Compliance at (202) 366-5308 (FAX (202) 366-1024).

Sincerely,

Samuel J. Dubbin Chief Counsel

Enclosure

ref:122 d:4/24/96