AFAIK lane departure in most cars is just a warning -- lights on the dash or a buzzer/beep or such (both of our cars are too old to have it but that's how it works on DD's Honda Pilot). I find it annoying but, then, I'm not typically dozing off at the wheel so maybe I'm not the target customer for this feature. There are cars which can drive themselves enough to correct for what it sees as a lane departure or a road obstruction but I think they cost much more than the cars most of us drive daily and they all let the driver override the car's initial action with the steering wheel, brake, etc.