Makes a bit more sense than charging by how efficient it is at burning gas. Costs should be skewed so that commercial operators who are causing 99% of the road damage, are paying to fix it; not passenger/commuter vehicles that weigh <10,000lbs.

The problem with that is it becomes a regressive tax that impacts the price of all goods transported by truck and raises the prices of basic necessities.

I think the suggestion I saw that all road maintenance should be paid from the general fund makes the most sense.

It's more complicated than that.

The fourth power law is only an approximation. If the road is designed for higher weight then the impact of larger loads is less. From https://en.wikipedia.org/wiki/Fourth_power_law

> A 2017 report commissioned by the New Zealand Transport Agency found a wide variation in the best-fitting exponents for a power law on 4T axle loads vs 6T axle loads, depending on the current condition and type of the roading. As a very rough summary of its highly detailed findings: A 9th-power law is most predictive when the road is barely able to withstand the 6T load; and the per-crossing damage is roughly linear to axle-weight when the pavement is able to withstand much higher loads than 6T per axle.

Highways (which this link focuses on) are designed for a heavier load than, say, residential streets.

A mid-size SUV is, what, 1 ton per axle? And a semi is max about 10 tons per axle (I don't know the average). And there are more SUVs on the highway than commercial trucks.

And in any case, there's already a Heavy Vehicle Use Tax which is meant to fund the additional maintenance demands caused by vehicles over 55,000 pounds.