[csense]

> What mechanism of paying for roads would you propose?

There are two purposes of the gas tax: (1) To pay for roads and (2) to provide incentives to conserve a valuable, limited resource (gas).

If we switch over to electric cars, taxing electricity makes sense from the standpoint of (2) because it's the valuable, limited resource that's being consumed by driving.

From the standpoint of (1), literally any source of government revenue will do. You can tax electricity. Or you can tax property (a lot of land's value, especially commercial / industrial, goes away if it isn't connected to a good road system). Or you can just use the general fund (basically everybody benefits from the enormous cross-industry economic gains of having functioning transportation infrastructure, so everybody should pay for it).