Does what I do with a vehicle subject me to FMCSA or does the size of the vehicle regardless of what I’m doing with the vehicle subject me to FMCSA safety rules and regulations?
Answer: All of the above.
Determination if a trip is DOT regulated is made on a trip-by-trip basis, based on:
(1.) Intent of the trip; or
(2.) The Federal Motor Carrier Safety Regulations (FMCSRs).
Trip — is a one-way movement of a person or vehicle between two points.
Example: You take half of the seats out of a 15 passenger van so you can carry, at most, only 8 passengers (and escape many regulations), but occasionally have ten or twelve passengers and have those extra passengers sit on their luggage. Clearly, the intent on those trips carrying extra passengers is to haul more than eight passengers.
The key regulatory phrase is “Designed or used.”
Many times a vehicle or re-purposed or modified after it comes from the manufacturer. An old school can be turned into an RV or used as a truck. As such, it would not be a “bus,” but depending on the intent of user, it could become a federally regulated vehicle if used in commerce.
Note: Your state may have its own rules for the type vehicle you are operating or the type of operations you are engaged in (limo, towing, farm, commercial, etc).
FMCSA is the regulatory arm of the Unites States Department of Transportation (USDOT) and means: Federal Motor Carrier Safety Administration.