[syzarian]

A 2000 pound vehicle driven an average of 15000 miles per year does $x of damage to the roads. X is a calculable figure. Tax the vehicle to at least pay $x. If it is in the pennies then tax that amount. That a heavier vehicle does more damage just means calculating the appropriate amount to tax it.

[ndsipa_pomu]

It could work out that it costs more to implement the smaller vehicle tax than it would recover in revenue. Also, there's a major problem with logistics companies having considerable power over politicians, so I can see problems with getting them to pay for their considerable share of the road repair costs.