Interpretation ID: nht88-4.25

TYPE: INTERPRETATION-NHTSA

DATE: 12/01/88

FROM: CONRAD S. BROOKS -- ENGINEERING MANAGER FISHER ENGINEERING

TO: ERICKA Z. JONES CHIEF COUNCIL -- NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION

TITLE: NONE

ATTACHMT: ATTACHED TO LETTER DATED 03/20/89 FROM ERIKA Z. JONES -- NHTSA TO CONRAD S. BROOKS, REDBOOK A33(8); STANDARD 205, STANDARD 120, PART 571.3

TEXT: Dear Ms. Jones:

I have heard differing opinions pertaining to federal regulation of four wheel drive vehicles with snowplows since becoming engineering manager at Fisher Engineering. Will you please furnish a written ruling on the following topics regarding snowplow ap plications:

Mr. Michael Kastner, the National Truck Equipment Association Government Affairs Coordinator, verbally confirmed the following statement yesterday as a result of phone conversation(s) with NHTSA. Please confirm in writing that the substructure for a sno wplow mounting that is permanently attached to a four wheel drive may be attached to and be forward of the front bumper without violating existing or proposed vehicle safety standards.

Is the snowplow blade, being detachable and used only a few hours each year, considered as part of the vehicle payload when it is attached? Does this exempt a vehicle, with the blade attached and raised, from having to meet the Front Gross Axle Weight R ating restrictions?

Is there a specific limitation of what percent of the vehicle curb weight that can be supported by the front axle? The Ford Truck and Body Builder Layout book specifies sixty-three percent maximum. If the portion of the curb weight on the front axle is only dictated by vehicle performance, can you suggest a source for some general guidelines to avoid performance testing?

Thank you for your assistance.

Sincerely,