SUVs are the result of a loophole whereby they are considered "trucks" for fuel efficiency regulatory purposes.  

Thus they should also be considered "trucks" for state regulatory purposes, including vehicle taxes, lane restrictions, and all the rest of it.  

The way to deal with the "cars only lane" situation is:  vehicles below such-and-such height and weight.   If someone wants to build a micro truck with weight & dimensions of a car, and use that lane, fine, let 'em.