Consider police vehicles, ambulances and utility maintenance vehicles. Does anybody really think they should have to pay tolls? A real market forces purist would say yes, but in reality passing along those costs efficiently isn’t practical. Similarly in theory all roads could be toll roads, but the cost of raising those tolls would massively increase the cost of the road infrastructure, driving up tolls in a vicious cycle. The gas tax is a reasonable compromise by taxing road use indirectly, it doesn’t capture the differing costs of different segments of roads and the demands on them, hence tolls on specific roads. So in the real world you can’t just treat everything like a nail and hit it with a market forces hammer. It’s a powerful and useful tool, one of the best we have, but still needs to be wielded responsibly with an eye to the intended outcome.