My wife and I were involved in an accident where we were stopped and a vehicle rear-ended us at approximately 45mph, centered on the rear of the truck. My wife was in the passenger seat and I was driving. My seat collapsed backwards completely, and my wife's seat collapsed within about 2 inches of the rear seat. When mine collapsed, the headrest came out most of the way, and I slid backwards, hitting the top, back of my head on the rear seat just below the head rest, breaking the skin and leaving a mark of blood visible in the photos.