How do I determine whether I must comply with the Federal Motor Carrier Safety Regulations or not?

Any self-propelled or towed motor vehicle used on a highway in interstate commerce to transport passengers or property when the vehicle has a gross vehicle weight rating or gross combination weight rating, or gross vehicle weight or gross combination weight of 10,001 pounds or more, is subject to the Federal Motor Carrier Safety Regulations. In other words, if you are pulling a trailer and your truck and trailer have a combined gross vehicle weight rating of 10,001 pounds or more, you are subject to the regulations when you are using the vehicle(s) in the furtherance of a commercial enterprise.