As discussed in this article, the government is busily ignoring its own reports and its own advisers. Instead, they're trying to make it harder to implement life-saving policies like ULEZ, LTNs and 20mph zones, and even trying to make it harder for councils to fine motorists who break the law (more great stuff from 'the party of law and order'!).

There's no such thing as road tax, but full duty, which motorists do pay, has not risen. It's been frozen for, I think, 14 years. Hunt froze it again the Budget just the other day! There may be other car-specific taxes I'm not aware of and you're sort of right that the overall tax burden has increased, but I don't know how much that applies to motorists specifically.

EDIT: Sorry, I forgot to add: there's one important sense in which clean air policies benefit motorists more than anybody, because the people most exposed to air pollution are people in cars. So, proven effective clean air policies like ULEZ certainly benefit motorists' health, which is why I described the government's new strategy as 'supposedly' pro-motorist. Not sure you can describe a policy to make people breathe poisonous air as 'pro' that group!