The City that I work for took all the Ford Crown Vic PD cars in and they cut down a bolt in the rear of the vehicle near the frame. They told us the bolt was puncturing the fuel tanks during rear impact crashes, and as a result Officers were burning to death.
Many are probably correct by asserting that many of the crashes are unsurvivable, but many of the autopsies show the Officer died from burning to death instead of the impact of a collision.
You drive a vehicle that harnesses the explosive power of up to 300 sticks of dynamite for a fuel tank.
If it gets hard enough, it leaks and it burns. It's called LIFE. IF you want to avoid this problem, start issuing M1 tanks to police officers.