Be honest, why do you tailgate?

[mjmacky]

I ruled out the British possibility based on the fact he/she was speeding.

[aryke]

I have no idea why people would increase the chances of crashing in order to do it.
However, its proven to reduce the amount of fuel you use as tail gating allows the car in front to deal with the drag from the air passing over the car.

It's like in cycling where the guy at the front of the pack (in the velodrome) uses approximately 30%-50% more energy.
That's why they move behind if they can't keep up the strain.

[mjmacky]

It's called drafting, and you can get 50% more miles to the gallon (or 33% less liters per 100 km).

It would have to be a tractor trailer in front of you though.