We should have a social network for driving. Everything's network connected these days, connect cars, and then implement a system where if you see a guy being a complete douche, you can thumbs down his car in some online system. Like, with a touch of a button on your steering wheel, that scans up his license plate and downgrades him in some social network for cars.
If "enough" people downgrade the same person, they should actually have their license suspended. I don't know what "enough" is, but maybe it should just be the 1% of drivers with the worst ratings get voted off the road. Also, when you're deciding whether or not to let someone into your lane, it would pop up some information telling you whether or not they're a real asshole, or whether they've been nice to others. Then decide whether or not to let them in.
I think it would be much more effective than traffic laws, letting drivers themselves collectively vote the assholes off the road. There's a bunch of details that would have to be thought through to make this work--maybe each driver should only be allowed to rate only one other driver a week, and only ever rate the same other driver once in their life, to prevent everyone from hitting the downgrade over the most minor things, or harassing someone. But I think with some thought it actually could work.
Probably wouldn't even need to have traffic enforcement. Just let other drivers decide what's reasonable road behavior, and what's unacceptable. Police could concentrate on more serious crimes and leave the speeders, unsafe lane changers, etc., up to the driving public to deal with.