Toll tax is a specialized tax and cannot be compared to a road tax. You need to pay a toll tax in some highways and roads. This tax structure is known as toll tax and is paid for maintenance of the road, highway or bridge. These roads are built exclusively using a BOT or build-operate-transfer plan and hence your toll tax money is used to cover the expenses for the road or highway. You pay an annual road tax allowing you to drive your vehicle on the roads laid down by the government. Road taxes are fixed by respective state governments and that is one of the reasons why prices of vehicles vary in different states.