Everyone travels with a personal tracking device, except for those who choose to opt out of modern society, what you present as a future threat can be easily done today with little effort by law enforcement.

It's trivial to determine the speed a person travels down a highway from GSM timing advance data. In most countries on Earth this metadata is mandated to be held for a certain amount of time by service providers.

Like all laws, it's selective, and there's only so many prosecutors, the moment they even try to charge the first person is when that government mandated tracking device in your pocket starts losing its value.

The angle of the plate wouldn’t allow it.

What they can do is feed the movements of all vehicles into a big data platform and infer which car went where...

Just waiting for the Speed Enforced by Satellite highway signs... But in seriousness, the angle wouldn’t work.

...unless it's cloudy.