What I find interesting is that the OP asked a question about the different rates charged to someone driving a DRW truck as opposed to a SRW truck, each one pulling the same 2 axle trailer. So far, there have been several responses from people driving a MH who claim they have had inconsistent charges. That may be so, and I have no argument with them, as they have obviously experienced difficulties in determining whether they are a bus, a truck or whatever. BUT, the OP's question was regarding a DRW truck vs a SRW truck, and there has only been 1 response (plus mine) so far that addressed that scenario. All the rest were from folks driving a MH or bus or whatever. This is not to diminish their concerns about inconsistent charges, but the OP's question was about the difference between a single rear wheel (SRW) pickup and a dual rear wheel pickup (DRW). All the rest is interesting reading but (respectfully) does not answer the OP's question.