Anybody heard of this?

[Ginger]

a car that knows the current speed limit and automatically gives you a ticket if you go over it, yep, don't say it won't happen. Remember Demolition Man?

There was the incidence of the rental car agency attempting to do that. The court the tried their case threw it out saying that the car agency didn't have the right to enforce the law... which was an outright mockery of the renter's legal right to protect their assets. The real reason they wouldn't let it happen (and why you won't get ticketing agents attached directly to cars) is that it infringes on the state's monopoly of ticket revenue collection.

If a county/state/municipal authority needs more money they can step up enforcement. Start issuing 5/10/15 over tickets... you can't issue those tickets if people know that every time they exceed the limit at all they'll be fined - people just won't exceed the limit, either that or people will start seeing the ticket as a 'go faster pass'and think of it as the price of getting somewhere quickly. Either way the state loses.