On Saturday, February 9, 2019 at 2:21:03 PM UTC, NY wrote:

Given that VED is graduated partly by vehicle weight, for HGVs, it is hard
to say that it is not related to the damage the heavier vehicles cause and
therefore the greater road maintenance needed, even if there is no formal
link.

It is dependent on the amount of pollution in the form of CO2 emissions that the vehicle pumps out. Some low polluting cars pay nothing at all, even though they weigh over a tonne.

https://pbs.twimg.com/media/Dy-I1CqXQAAEgf_.jpg