As someone who had to study civil engineering as an undergrad a lot of the formula are empirical. 3rd power law might not coorelate with degradation of some roa

As someone who had to study civil engineering as an undergrad a lot of the formula are empirical. 3rd power law might not coorelate with degradation of some road some road while others might exhibit 5th power law. However if I recall correctly the correlation between road wear and axle load was ^4.