Food for thought: The below was taken from the Federal guidance book on how to interpret the DOT rules.

"Question 21: Does the exemption in §390.3(f)(3) for the ‘‘occasional transportation of personal property by individuals not for compensation nor in the furtherance of a commercial enterprise’’ apply to persons who occasionally use CMVs to transport cars, boats, horses, etc., to races, tournaments, shows or similar events, even if prize money is offered at these events?

Guidance: The exemption would apply to this kind of transportation, provided: (1) The underlying activities are not undertaken for profit, i.e., (a) prize money is declared as ordinary income for tax purposes, and (b) the cost of the underlying activities is not deducted as a business expense for tax purposes; and, where relevant; (2) corporate sponsorship is not involved. Drivers must confer with their State of licensure to determine the licensing provisions to which they are subject."

This interpretation may not can be used with a police officer but it definitely can be used in court.

I don't think the 10,000 pound rule is a Federal rule. And only Federal rules can restrict interstate commerce. States have no right to pass laws having to do with interstate commerce. That is given to the Federal govt by the Constitution. Hopefully he gave you a reference to the 10,000 pound rule. I would love to read it