8011 S. Cook Way
Littleton, CO 80122
Dear Mr. Murphy:
This responds to your request for an interpretation whether a vehicle with two main wheels and two auxiliary wheels may be considered a "motorcycle." As explained below, the answer is yes.
Your letter describes your vehicle's design as having two main wheels, and left and right side auxiliary wheels that are elevated off the ground. You informed Dorothy Nakama of my staff that the auxiliary wheels are to facilitate vehicle turning, when no more than three wheels would touch the ground.
NHTSA defines "motorcycle" at 49 CFR Section 571.5(b) as:
a motor vehicle with motive power having a seat or saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground.
In a previous letter, NHTSA stated that a two wheeled vehicle whose auxiliary wheels are used only for stabilization in turns is considered a "motorcycle" since the vehicle is designed to travel on not more than three wheels in contact with the ground. (See enclosed letter of June 11, 1986 to the NY State Department of Motor Vehicles.) Since your vehicle is also designed to travel with at most three wheels in contact with the ground, we would consider your vehicle a "motorcycle" for purposes of compliance with the Federal Motor Vehicle Safety Standards.
I hope this information is helpful. If you have any further questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992.
Philip R. Recht Chief Counsel
Enclosure ref:571 d:1/3/95