When a driver follows the car in front leaving little or no stopping distance especially at high speed.
This behaviour may stem from any or all of the following:
Lack of imagination.
Never seen pictures of a road accident.
Someone who only managed to pass his/her driving test by giving the examiner a blow job
Having an extra chromosome.
Loneliness or pathological nosiness
Drink or drugs.
Being born with somekind of twat
Driver is busy trying to figure out what the indicator lever is for.
A guy that is so dammed horny
that he just can't wait to get to his mothers house.
Many female tailgaters like to put a sign in the rear window of their car stating that there is a 'Baby on Board'.
Tailgating may lead to a car fuck
Despite the 70mph limit I clocked 120mph while attempting to shake off the tailgater.
It was pitch black
on that road, when I turned my car lights back on I observed that the tailgater had dropped back to reasonable distance.