Right now we think of tailgating with football. I believe that it started with soccer, they have crazy fans who would hang out around that stadium.
A 'tailgate' is the back part of a truck or heavy goods vehicle. Drivers who stick too close to the back of another vehicle were said to be having a 'tailgate party', which was then just shorted to 'tailgate'.
Blue Ribbon - 2003 Tailgating was released on: USA: 17 November 2003
Following the vehicle in front of you to close for comfort is one form of tailgating. This is a bad habit that can lead to having a rear end collision. Tailgating can also mean fixing/having a lunch from the tailgate of your vehicle.
They love tailgating.
I Brake for Tailgaters!
Tailgating
Tailgating refers to the action of driving so close to the vehicle in front of you, that you may not be able to stop in time or avoid collision. Tailgating can result in rear-end colissions and therefore it's illegal in many jurisdictions.
Tailgating
Mansome - 2012 Tailgating with Cutlets 1-74 was released on: USA: 15 November 2012
Apocalypse When Tailgating the End of Days - 2012 was released on: USA: 4 November 2012 (theatrical premiere)
Art Mann Presents - 2005 Tailgating in the ATL was released on: USA: 30 October 2013