Actually we little guys have it pretty easy. When we fuel up, we pay a simple cents per gallon tax, and whatever state we happen to be in gets to keep it all. There's an additional Federal tax, but it doesn't really enter into the equation.

When a commercial hauler buys fuel, a tax is collected, however it's not considered a fuel tax. It's a "road use tax." Theoretically, the state where the fuel is sold is only supposed to get it's share, based on the pro-rated number of miles the truck is driven in that state. When the driver enters the next state, he/she has to prove that the tax was paid, and tell them exactly where he's going and how many miles will be driven in that state, so that the second state can collect their share of the road use tax that another state has collected.

This works fine, except when you buy fuel in California, where they maintain that they get to keep it all and refuse to pay anything to another state. This means that the driver/carrier has to pay the tax twice on any fuel purchased in California.

In the interest of fair play, of course, California does claim their share, for miles driven in California, from other states where fuel burned in California may have been purchased, which incidentally again may or may not result in the driver/carrier paying the tax twice, since some other states are becoming reluctant to forward to California the bit corresponding to the portion of fuel burned there but purchased elsewhere.

As to toll roads, a fairly recent survey put the average turnpike toll at about 15 cents per mile per axle, but many places charge a non-linear rate that adds in a "gross weight" charge in addition to the per axle fee for vehicles with more than 3 axles. (i.e. car with small trailer, or large pick'em up). Bridge tolls etc. tend to be much higher than the cents per mile rate, especially for heavy vehicles, which in some areas does have an impact on people towing moderately large campers etc.

John