Rubber necking

To turn your head while passing by something/someone or someone/something is passing by you. Either slowly turning your head to track your eyes on the spectacle or to repeatedly turn your head to keep looking at it.

The act of looking at something as you drive by. People do it when they come past an accident. Also tourists do it when they are observing the scenery when they are driving. It quite often causes traffic to slow down because the person looking generally slows down a bit to look out their window or windshield.

The reaction of drivers as they pass by an accident scene; to drive aimlessly while looking away from the road at something happening off road.

when all of the sudden traffic gets really heavy and there is no reason for there to be so much traffic until you move up enough to see an accident. all the cars are slowing down and rubber necking to see the car accident which causes another accident and more rubbernecking and so on.

turning and looking a hot woman walk by when you are with you girlfriend

to do a double take or look back at a hot or attractive person while walking.

A person(or group of people) that are genuinely and naturally asshole.