I don’t know how other cars behave on the road, but I’ve been driving a model 3 for almost a year, and it’s like having a co-pilot. The steering wheel vibrates when you’re driving out of your lane. The car beeps if it sees something dangerous. Cruise control keeps distance to the car in front. If a car is entering the highway and you’re on the right lane, it will brake strongly to let the other car in (in this regard it’s pretty paranoid, I guess that’s a common cause of accidents).