Comment by chrismorgan

I remember my dad telling me that when I was in my late teens. That it’s the fourth power startled me.

To give an idea of what this means:

For a 50 tonne semi-trailer with five axles, (⁵⁰⁄₅)⁴ = 10,000 units of damage.

2 tonne vehicle with two axles, 1 unit of damage.

That one truck, only 25 times as heavy as a pretty heavy car, is doing 10,000 times as much damage to the road.

Thus indeed if you have basically any heavy freight at all on a road, the rest is negligible.