THE VEHICLE WAS STOPPED, WAS INVOLVED IN A 3 CAR COLLISION. THE VEHICLE WAS HIT FROM BEHIND BY A 1985 CADILLAC FLEETWOOD TRAVELING AT AT LEAST A MODERATE RATE OF SPEED. THE VEHICLE WAS PUSHED INTO A 2002 AUDI (I BELIEVE IT WAS) SUV. DURING THE COLLISION THE DRIVERS SEAT BACK FAILED AND COLLAPSED INTO THE BACK SEAT. I BELIEVE IT WAS THE SEAT ADJUSTER THAT FAILED. THE DRIVER SUSTAINED A CONCUSSION DUE TO THE COLLISION AND THE SEAT FAILURE. THE VEHICLE WAS ON A STATE ROAD, AND WAS STATIONARY.