The excise tax on your car used to be a percentage of value, there were other flat things (monorail, etc) that were flat $ per car. The whole thing got torn up years ago and made flat $30/car, but it's creeping in various ways now.

To be clear I wasn't arguing for the old vehicle tax model, only pointing out that there are significant bureaucratic and convenience issues with user fees... And personally, I think they also discourage usage, and dis-proportionally provide access to 'expensive' things (see $70 fishing licenses) to those with greater disposable income -- not something I appreciate for our shared/natural resources.