But fuel usage it not proportional to mileage and weight across vehicle classes, and damage is proportional to axle weight to the fourth power.
A diesel sedan might use 1.25 gal for 100 ton-miles, while a tractor trailer might use a third of that (though, to be fair, I thought this would be a bigger delta before I looked).
But then if you look at "Equivalent Single Axle Loads", a tractor trailer is ~2 ESAL while a diesel sedan is ~0.0003 ESAL. So we're talking maybe 0.13 ESAL/gal for the former vs 0.0001 ESAL/gal for the latter.
A diesel sedan might use 1.25 gal for 100 ton-miles, while a tractor trailer might use a third of that (though, to be fair, I thought this would be a bigger delta before I looked).
But then if you look at "Equivalent Single Axle Loads", a tractor trailer is ~2 ESAL while a diesel sedan is ~0.0003 ESAL. So we're talking maybe 0.13 ESAL/gal for the former vs 0.0001 ESAL/gal for the latter.