Fully stopped in 405 gridlock, I got rear ended in the Honduh Accordian over the weekend.  I broke the seat back and the seat scootcher-upper track thing, and I'm not a big guy.  Poor brother in law sitting in back gets his knees crammed by my seat breaking.  I don't know if it was designed to fail that way or not, because I seemed to have gotten bruised the least.  My passenger did not break her seat, and her knees got banged into the dash.   
  
  
I must be slow because it was like 3000MS after the initial impact that I was like WTF just happened??!! (driver did not brake at all, no screeching tires, no nothing).  1ms after I realized I'd been rear-ended, surprise! a SECOND car bashes us again.  The cabin stayed intact, though the roof buckled.  I'm glad the car held up so good.