Take a look here....Interesting discussions about "interstate commerce',and how the states are defining,or trying to interpet.
http://www.thetruckersreport.com/tru...or-no-cdl.html
Just one site of the hundreds out there,and you could spend hours looking up each states laws pertaining to what's required,and defined as the laws apply to hauling a race car.The catch they're using is "you're involved with Interstate Commerce if you pay to enter,win money,and use as a tax write off".So therefore you're subject to that certain states trucking rules pertaining to weight,lenght,and license requirements.
Again all I can say it's a money grab