this might not be the best place to advocate a psychological screening in order to drive.....some people are very laid back until they get behind the wheel. Personally i just let them go and dont pay any attention to them. If someone is drifting into my lane ill bang the horn, other wise i just watch out for what others are doing and fall back and let them go far on if they are swerving in and out of traffic or popping wheelies on a rice rocket. I figure somewhere down some road i will be passing them anyway when they inevitably crash.