The rules do work for the most part, but they can't be effectively enforced.
Outside of speed and traffic light cameras, I don't see any way to enforce most traffic laws that would make getting caught likely enough to deter breaking the law.
Even if you double or triple the number of police officers on traffic duty, that means instead of seeing two cops per week for a total of 30 seconds during your weekly drive time, you see four for a total of a minute.
How many time do you see cars speeding or running stop signs? How many times do you see cars stopped for doing that. Now, double the number of cars you see stopped. Think that will make a difference? Instead of having a 99.98% chance of getting away with running that stop sign, it'd be 99.96%. Do you think that's even going to register on the average driver?