According to the info at the site above, Oregon has taken note of a few folks trying to avoid the gas tax and has a alternative per mile tax for EV's to go into effect soon.
A tax on walking or riding a bike will probably follow.
PA is talking about raising the gas tax in part because vehicles are becoming more efficient and in part because the electrics aren’t paying anything.
A mileage based tax would hit everyone across the board. And yes, I’d be for tamperproof odometers and annual inspections of bicycles. A lot of transportation $ goes toward creating bike lanes.