A Ford Fiesta breaks down on an isolated road and a BMW 750 stops to help the old driver.
"I will tow you to the next service station, but if I go too fast please flash your lights so I will know to slow down"
They setup and proceed down the road slowly and after a mile a Porsche Boxster speeds pass at 120mph, the BMW driver forgets about the Fiesta and guns it to catch and try to pass the Boxster.
Just as all three of them pass a speed trap, the amazed cop radios HQ:
"You are not going to believe this but I have a BMW and Porsche raceing past at 120mph and a damn Ford Fiesta is on their ass flashing his lights to pass!"