The DOT considers any vehicle over 10,000 lb. and driven for a business purpose a commercial vehicle (CMV). If there is commercial advertising of any kind on the rig (including the car on the trailer) it COULD be considered a CMV by a local officer. Any driver of a commercial vehicle must comply with the DOT rules, including DOT physical cards for the drivers, logbooks and hours of service rules, not to mention other things like NO alcohol in the rig unless it's on a manifest. CDLs are required to drive a CMV over 26,000 lb.
Any CMV should have a DOT number.
States have varying rules which could be stricter - like certain licenses for certain weight vehicles. If you're out of the state in which the vehicle is licensed, DOT rules apply mostly, but there are exceptions. State rules also determine whether you must stop at a weigh station. Minnesota wants every truck over 9000 lb. to stop...in Washington and Oregon, it's 23,000 IIRC.
So is your race car on a trailer a CMV? If it's under 10,000 lb., no. Over 10,000 lb. - likely. Most race cars on trailers are flying under the radar...the advertising on the sides of the rig and no DOT number visible COULD be probable cause for a stop...as could blowing by a weigh station - as one Minnesota crew found out.
One more thing - the DOT rules say RVs MAY NOT be CMVs...they are outside the rules completely. As always, your state rules may vary.
Don't pay any attention to advice you see in forums - including mine. A good OFFICIAL site is
http://www.fmcsa.dot.gov.
Bruce
Have a DOT card
and a logbook
