Any car that's sitting in stop and go traffic isn't going to get nearly the mileage they would get when driving at free flow highway speeds. As the vehicle fle

Any car that's sitting in stop and go traffic isn't going to get nearly the mileage they would get when driving at free flow highway speeds. As the vehicle fleet transitions to higher mileage vehicles, the gas tax can be adjusted to compensate based on overall usage and the number of registered vehicles. And making those adjustments would cost far less money compared to setting up additional tolls or a VMT based taxation scheme.