A gas tax was in many ways the perfect (as perfect as one can get) tax. You paid into the road system (all of it) according to how much you used it.
This is, of course, completely wrong.
What you want from a gas tax is for it to maintain the roads, right? And you'd think that the heaviest vehicles, which do the most damage to the roads, pay the most, right? And they sort of do, but not really, because the heaviest vehicles only use a few times more fuel but do multiple orders of magnitude more damage. Passenger cars do basically zero road damage, unless the road already has big holes in it, in which case it's possible for them to wear away at the damaged edges and make the holes bigger. Heavy trucks do basically all of the road damage. The pass car gets what, 40 mpg? The heavy truck gets around 8-10 while cruising on flat land, maybe as little as 2-4 while pulling a grade, so: It can use an order of magnitude more fuel but mostly only uses two to four times as much, but does more like two orders of magnitude more road damage all the time.
The trucking industry will happily tell you that those numbers come from a study they think is discredited because "When a highway is properly designedâ¦it will not be damaged by the traffic it is designed to support" but it isn't, for reasons described in the summary of this report, mostly this:
Federal weight limits do not apply to at least 95 percent of the Federal-aid highways. In addition, a grandfather clause in existence since origination of Federal weight limits in 1956 stipulates that truck weights which were permissible in individual States at that time can remain in effect indefinitely.
IOW, while what they say about correctly designed roads is essentially true, it's irrelevant. It's also not completely true, because those roads also have to be correctly maintained. How many times have you driven on a bad patch intended to be temporary, where a section of road really needs to be re-laid because of damage to the roadbed? How many times have you still been driving over that "temporary" patch years later?
TL;DR: The gas tax was always a handout to trucking companies and therefore also oil, rubber, and gas companies; The gas tax always hid the true costs of modern interstate commerce, when the shippers always should have paid more and those costs should have been rolled into the price of the goods to which they apply, so that "the market" could make corrections through price pressure, but that was deliberately suppressed through the use of a "gas tax" which you're now lauding.
Personally, I think road maintenance should come out of general tax funds. Everybody benefits from roads, directly or indirectly.
Now this is 100% spot on. The road network benefits everyone and therefore it should be paid for from general funds, to the extent to which that makes sense. That is to say, less money should be spent on it, and more on rail, where these issues are much easier to mitigate. A rail line can carry much more mass with less impact than using highway lanes, it's easier to maintain the rail bed (you can see and access it) and anywhere the traffic justifies it, it's a much more sensible solution. And it's one we would have been using a lot more for right now if not for the laughable gas taxes for road maintenance bullshit.
Rational solutions require not expecting public services to turn a profit, so we cannot have nice things as long as we are doing that. Only one party is like that. We must destroy that party if we are to progress as a society.