In order to avoid the summer traffic jams, a familly sets off on vacation at dawn in its brand new minivan. Tom, the father, sets the electronic speed regulator at 80 mph. At the moment when Julia, at the end of her tether due to yet another of her father-in-law's blunders, demands that they turn back, Tom notices that he is no longer in control of the vehicle. The electronics no longer respond and the speed is blocked at 80 mph, and then the speedometer steedily starts climbing to 100 mph. None of the manoeuvers to slow down the car have any effect.
An out of control car, six passengers on board having tantrums, and a huge traffic jam waiting for them less than 120 miles away.