That's an interesting technical problem. PID controllers answer a similar problem in control theory. I don't have the answer here, and I'm not certain there is one. It really depends on how many more cops we'd need to get to a state where enforcement can be rigorous, and whether we as a society prefer the tradeoff of paying for those enforcers to get safer roads. Tough question. But I like tricky questions aimed in a true direction better than easy, wrong answers like, "ticketing people has no effect on speeding."