The systems basically work the same: a series of cameras, lasers or infrared sensors integrated into the car (on the back side of the rear-view mirror, in the bumper or behind the windshield, for instance) monitors lane markings in the road.
Patrick's car careened back into David Ragan, flipping her hood over the windshield and shredding the left front fender as protective foam from the driver's side door flew onto the track.