Interpretation ID: 23097.drnc

Mr. William E. Lawler
Manager, Specifications
Indiana Mills & Manufacturing, Inc., (IMMI)
18881 U.S. 31 North
P.O. Box 408
Westfield, IN 46074-0408

Dear Mr. Lawler:

This responds to your request that the National Highway Traffic Safety Administration interpret the metric conversion of one inch in Standard No. 209 Seat Belt Assemblies, at S4.3(j)(1), as 25.4 millimeters (mm), not the specified 25 mm. You do not explain why you prefer 25.4 mm.

The 25 mm measurement was adopted as part of an initiative to convert English measurements in the Federal motor vehicle safety standards to metric measurements. We proposed to convert one inch in S4.3(j)(1) of Standard No. 209 to 25 mm, in accordance with the principle that we generally favor equivalent, not exact conversions. We adopted the 25 mm measurement after publishing notice of the proposed conversion in the Federal Register (April 21, 1997; 62 FR 19253), and receiving comment on the proposal. The 25 mm measurement is clearly specified in Standard No. 209. We cannot interpret the provision as 25.4 mm.

We note, however, that we are considering rulemaking to amend S4.3(j)(1). We will consider including a proposal to change the 25 mm value to 25.4 mm.

Please contact us if you have further questions. For information about metric conversion principles, please feel free to contact Ms. Dorothy Nakama of my staff at (202) 366-2992. If you have questions about Standard No. 209, you may contact Mr. Otto Matheke at the same telephone number.

Sincerely,

John Womack
Acting Chief Counsel

Enclosure
ref:209
d.11/16/01