> If the pollution is from tires, then tax tires.

I don't think you can tax tires high enough that it will make a difference, but the same is also true if we attempt to tax by weight. Any tax is going to be the equivalent of slapping €10 on a plane ticket. It's not enough to stop the behaviour, but might be enough to keep some people driving on dangerously worn down tires.

It also doesn't matter if the car is an EV or ICE, the behaviour we want to limit is driving. The idea of taxing the tires could of cause lead to development of tires that doesn't shed microplastic.

I think it's one problem at a time. Curbing driving is a separate goal. Reducing pollution from tires is potentially a smaller and direct goal. Either people drive less or use tires that don't shed. That's why I think the tax should be related to the composition of the tire. I agree that people may end up driving on bald tires, and we don't want that. I'm British but live in the US and I think it's utterly insane that vehicles aren't required to have annual or bi-annual safety checks. An emissions test is not a safety test. A safety test involves breaks, tires, and headlamp alignment. I really wish we had headlamp alignment tests in the US. I want the 'freedom' to drive knowing the other cars are safe or the other driver is going to be charged if they are caught or are involved in an accident.

“ the behaviour we want to limit is driving”

By we, what do you mean? If this was true, we’d build walkable cities, public transportation and promote home office as much as possible.