Interpretation ID: 17173.wkm

Mr. Jimmie D. Gowen, Jr.
President/General Manager
Big John Trailers
Route 3, Box 950
Folkston, GA 31537

Dear Mr. Gowen:

This responds to your letter of January 26, 1998, as supplemented by your letter of March 12, 1998, in which you asked whether your knuckle boom loader trailers and your self-propelled loader carriers are subject to the antilock brake system (ABS) requirements of Federal Motor Vehicle Safety Standard (Standard) No. 121, Air Brake Systems. You explained that the two vehicles in question are primarily utilized at logging sites, but are capable of being towed to different job sites from time to time by use of highway tractors. Based on the information you provided, the answer is no, as discussed below.

Chapter 301 of Title 49, U. S. Code (hereinafter "Safety Act") authorizes the Secretary of Transportation, through this agency, to establish Federal motor vehicle safety standards applicable to new motor vehicles and new items of motor vehicle equipment. The Safety Act defines the term "motor vehicle" as:

[A] vehicle driven or drawn by mechanical power and manufactured primarily for use on the public streets, roads, and highways, but does not include a vehicle operated only on a rail line.

49 U.S. Code 30102(6)).

In your March letter you referred to and enclosed a copy of a letter we wrote to Mr. John N. Swearingen of Viking Trailers dated September 3, 1997. In that letter we determined that a knuckle boom loader trailer similar to yours is not a motor vehicle. We made that determination based on the intended use of the vehicle. Similarly, it is our opinion that your knuckle boom loader trailer and your self-propelled loader carrier are not motor vehicles within the statutory definition quoted above. They are utilized primarily off-road in logging operations but are occasionally transported over the public roadways from one job site to another at which they typically spend extended periods of time. In such cases, the on-highway use of the vehicle is merely incidental and is not the primary purpose for which the vehicle was manufactured. This is in contrast to instances in which vehicles, such as dump trucks, frequently use the public roadways going to and from job sites, but stay at a job site for only a limited time. Such vehicles are considered motor vehicles for purposes of the Safety Act, since their on-highway use is more than "incidental."

In summary, it is our opinion that your knuckle boom loader trailers and your self-propelled loader carriers are not motor vehicles, and therefore are not subject to the ABS requirements of Standard No. 121. However, if we were to receive information that your trailers were used on the roads more than on an incidental basis, then we would have to reassess this opinion. If we determined that your trailers are motor vehicles after all, then your newly-manufactured trailers and carriers would be required to comply with all applicable Federal motor vehicle safety standards.

I hope that this information is helpful. If you have any further questions or need additional information, feel free to contact Walter Myers of my staff at this address, by telephone at (202) 366-2992, or by fax at (202) 366-3820.

Sincerely,
John Womack
Acting Chief Counsel
ref:121#VSA
d.4/23/98