Michael V said:

dv said:

The Rev Dodgson said:

From TATE:

“A 1988 report by the Australian Road Research Board stated that the rule is a good approximation for rutting damage, but an exponent of 2 (rather than 4) is more appropriate to estimate fatigue cracking.

A 2017 report commissioned by the New Zealand Transport Agency found a wide variation in the best-fitting exponents for a power law on 4T axle loads vs 6T axle loads, depending on the current condition and type of the roading. As a very rough summary of its highly detailed findings: A 9th-power law is most predictive when the road is barely able to withstand the 6T load; and the per-crossing damage is roughly linear to axle-weight when the pavement is able to withstand much higher loads than 6T per axle.”

so:
1) It’s not that simple.
2) It’s the top end axle loads (i.e. heavy trucks) that do the damage, and the difference between mid-range and bottom of the range is not that much.

3/ a 2nd power law still means it is a x4 difference.
4/ there are hundreds of thousands of heavy trucks in Australia. There are fkn millions of 2 to 3 tonne utes being utilised as family cars.
5/ At this stage the use of heavy trucks to move goods is a necessity. The selection of a 2.5 tonne ute to be used as a family car is almost always a needless extravagance.

5+/ And because it is a “Work Ute” it, its fuel and its maintenance is subsidised through the tax system.

I’ve got a “soccer mum” SUV 7 seater. I’ve never lifted the panel right at the back to raise the 2 extra seats.