Taxes are collected to build and maintain roads among other things. Tolls are collected to repay debt accumulated for the construction of the road. It's a mystery to whom the money is owed. The debt doesn't ever appear to be repaid, and tolls remain indefinitely. Tolls are largely prohibited on Federal-aid highways. The amount that you are charged on a toll road varies depending on the size of the vehicle that you are driving without any explanation given. Tolls can be unexpected, especially if you are a visitor to the area. If you can't pay, you could receive an even more expensive ticket.