Interpretation ID: nht91-2.51

DATE: March 27, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Earl C. Lempke -- President, Delavan Industries, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 3-6-91 from Earl C. Lempke to Taylor Vinson (OCC 5720)

TEXT:

This responds to your letter of March 6, 1991, to Taylor Vinson of this office. You have asked whether there is "any Federal ruling stating that Trailer Clearance Lights are considered as Safety Equipment and as such are not be be included as part of the overall width of the vehicle." You have enclosed a copy of 49 CFR 323.20, the clearance lamp regulation of the Federal Highway Administration (FHWA), with the observation that this section does not answer the question.

I am pleased to clarify this situation for you. As the FHWA regulation states, "Clearance lamps shall be mounted so as to indicate the extreme width of the motor vehicle . . . ." This requirement is virtually identical to that in Table II of this agency's Federal Motor Vehicle Safety Standard No. 108 that clearance lamps be located "to indicate the overall width of the vehicle . . . ." In 1976, NHTSA issued an interpretation that was published in the Federal Register on August 23 of that year stating that "The term 'overall width' refers to the nominal design dimension of the widest part of the vehicle, exclusive of . . . marker lamps" such as clearance lamps. I enclose a copy for your information.

The FHWA concurs with this interpretation, and has provided us with some additional comments. Federal width limits apply only on the National Network highways (23 CFR 658, Section A). The width of commercial trailers operated on these highways is to be measured across the sidemost load carrying structures, support members, and structural fasteners, as stated in an interpretation published on March 13, 1987, a copy of which I enclose. That proceeding also determined that side marker lamps and any other "non load-carrying safety appurtenance" which extended beyond these limits were excluded from width measurements. This would include clearance lamps, and thus exclude them also from width measurements. In December 1989, FHWA issued an advance notice of proposed rulemaking to consider if a new approach should be adopted to determine which devices to exclude from measurements of vehicle length and width. I also enclose a copy of that notice. FHWA advises that its next notice on the subject should be issued soon.

Although under FHWA regulations, the States determine whether safety equipment is to be excluded from the measurement of vehicle width, we believe that the State determination must be identical to the NHTSA position. Federal law (15 U.S.C. 1392(d)) prohibits a State from enacting or maintaining in effect any regulation covering the same aspect of performance as a Federal motor vehicle safety standard unless it is identical to the Federal requirement. We believe that a State must also interpret an identical regulation in a manner identical to NHTSA's

interpretation.

Attachment

Copy of a portion of the Federal Register dated 8-23-76 regarding "overall width". (Text omitted)

Copy of FHWA interpretation dated 3-13-87, regarding 23 CFR Part 658, truck length and width exclusive devices. (Text and graphics omitted)