Car 1 is a Honda Civic. Perfectly ordinary, just like you find all over today.
Car 2 is the same model of Civic, but modified so that it has eight half-sized tires, four per axle. It has the same contact area with the ground and the same mass. It’s pretty intuitive that this would not significantly change the amount of road wear.
Car 3 has been modified relative to car 2 so that it has four axles with two wheels per axle instead of two axles with four wheels each. Same mass, same contact area, just distributed a bit differently. Can I prove that car 3 doesn’t cause 1/16 the damage of car 2? No, but I’d be very surprised if it did.
Yes, axle weight is a reasonable proxy, I don’t disagree. However, when making broad statements, it’s good to be as precise as possible.
Imagine three cars:
Yes, axle weight is a reasonable proxy, I don’t disagree. However, when making broad statements, it’s good to be as precise as possible.