So if if a 400 lb motorbike costs 1 penny per mile in road damage, the 4000 lb SUV should be paying 60 bucks and the 40,000 lb tractor trailer 1 million dollars?
The fourth power law (also known as the fourth power rule) is a rule of thumb which states that the stress on the road caused by a motor vehicle increases in proportion to the fourth power of its axle load.
So if if a 400 lb motorbike costs 1 penny per mile in road damage, the 4000 lb SUV should be paying 60 bucks and the 40,000 lb tractor trailer 1 million dollars?
Or is it divided by contact area?
First line of the linked wikipedia article.