REAR END COLLISION- AT 35-40MPH THE DRIVER SEAT WENT ALL THE WAY BACK & THE BACK OF THE SEAT WENT TO A RECLINING POSITION. I RECEIVED A CONTUSION ON THE BACK OF MY HEAD AND WAS KNOCKED UNCONSIOUS FOR ABOUT 50 FT. THIS HAPPENED WHEN THE PERSON BEHIND ME HIT A SPEED BUMP I HAD JUST GONE OVER.