Interpretation ID: nht81-1.33

DATE: 03/10/81

FROM: FRANK BERNDT -- NHTSA CHIEF COUNSEL

TO: DONALD W. VIERIMAA -- DIRECTOR OF ENGINEERING TRUCK TRAILER MANUFACTURERS ASSOCIATION

TITLE: NOA-30

ATTACHMT: LETTER DATED 02/09/81 FROM DONALD W. VIERIMAA TO FRANK BERNDT -- NHTSA, EXCLUSION OF THE TOWBAR OF A PERMANENT TRAILER DOLLY FROM THE FMVSS 108 LENGTH CRITERIA; LETTER DATED 04/04/73 FROM RICHARD B. DYSON -- NHTSA TO PAUL K. WILSON

TEXT: Dear Mr. Vierimaa:

This is to reply to your letter of February 9, 1981 asking for "exclusion of the towbar of a permanent trailer dolly from the FMVSS 108 length criteria."

As you indicated, an opinion by this office in 1973 excluded converter dollies and their integral towbar from inclusion in computation of the overall length of trailers (i.e. S4.1.1.3 which excludes intermediate side marker lamps on vehicles less than 30 feet in overall length). Even though a trailer might be manufactured with a permanent dolly, its function is identical to that of a converter dolly and there is no reason to distinguish one from the other for purpose of computation of overall length. Therefore, overall length may be computed exclusive of either the dolly or the tongue.

Sincerely,