Interpretation ID: nht72-1.7

DATE: 07/27/72

FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA

TO: Ford Motor Company

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of June 20, 1972, to Mr. Toms concerning general reference material in support of the proposals contained in Docket No. 70-27. Hydraulic Brake Systems. You ask that the NHTSA place in the file "The supporting data upon which the test sequence is based as well as the data used to determine the performance values based on the sequence."

The proposed test sequence is based primarily upon the test sequence of standard No. 105, which is that of SAE Recommended Practice J937 incorporated by reference. Parking brake lightly loaded vehicle, inoperative brake power assist unit, and partial failure tests not included in J937, were placed in the sequence in the order that appeared, in the judgment of agency personnel, most likely to provide realistic and undistorted results. The sequence, of course, is subject to revision on the same basis in the forth-coming final rule. General reference material in the Docket includes data from braking tests of eighteen 1970 automobiles, NBS Technical Note 557, "The Brake Pedal Forces Capability of Adult Females," and SAE 720032, "Evaluation of the Use of Automotive Braking Systems During a 7300 Mile Cross-Country Trip."