If this were to replace state and federal gas taxes, fine as this would then require non-gas or diesel cars to pay their fair share of road costs. And, how about requirement that all of these mileage taxes go solely to building and maintenance of roads used by those cars, thus no walkways, no bikeways, not other diversions.
That's what they did with tolls the NJ Turnpike and Garden State expressway in New Jersey. They were chartered to use tolls to pay for the construction and then the tolls would go away. They never did, for decades they just kept adding to the roads, spurs that went nowhere, just to keep that toll money coming in. Now they don't even bother with that. Those temporary tolls are damned permanent.
And so too will any new tax be.