The state of Washington imposes an "additional vehicle weight" fee on our car -- a Prius. Which is just the kind of puzzle I like to solve over my breakfast (don't judge).
The law comes down to this:
●If your car's registration first comes due on or before 7/1/2016, and it weighs more than 4000 lbs, you pay an additional weight fee.
●If your car's registration first comes due after 7/1/2016, you pay an additional vehicle weight fee. Period.
Makes perfect sense.
@ImagineThat So the additional weight fee is imposed without regard to weight?
@walterbays I was not being clear. Heavier vehicles, of course, wear out pavement and should be taxed accordingly. In WA this is accomplished by an "additional weight fee"--which for some vehicles is for weight over 4000 lbs, and for others is for weight over 0 lbs.
If your car weighed 3999 lbs and its first registration was 7/1/2016, you pay no additional weight fee; if your car was literally weightless but was first registered after that date, you pay a $10 "additional weight fee."
@ImagineThat https://www.insidescience.org/news/how-much-damage-do-heavy-trucks-do-our-roads