I know of at least 1 study on human behaviour, where an image of an eye was added to a bathroom and increased the number of people who washed their hands after using the facilities, that suggests people do in fact need the "threat" of feeling they're being watched to behave responsibly.
Ultimately, when you're in control of something with the potential destructiveness of a car, you do need to be monitored for everyone's safety. The only way to have a society without that level of monitoring is to have one without general access to cars.