There are some collisions scenarios where seat-belts, air bags and crumple zones will not help, but there are still escape routes!
The above photo demonstrates that, despite the propaganda, there are limits to what vehicle safety design engineers can accomplish to keep you safe. A collision like this is often caused by striking the side of a box-type, semi-trailer at high speed. Death can sometimes be escaped if you duck down because the severity of the impact is much less than it might seem. The upper structures of a car are soft, meaning that they become crushed and displaced at much lower forces than if the contact was made to the bumper level. So in this scenario, it is not so much that the change-in-velocity (Delta-V) is the killer, but more so that the structure of the vehicle has come into the occupant space. Seat-belts and air bags are of limited or of no benefit in this scenario. Fortunately these happenings are very rare.
Where scenarios like these occur, escape is still possible through new technology such as Automatic Emergency Braking (AEB). Thus sensors might detect the present of a tractor-trailer that is backing into a driveway and is straddling the lane in which you are approaching. You may not detect the trailer at night or in poor weather conditions but the sensor technology can. Brakes can be applied automatically without your approval, most likely resulting in your survival. AEB is perhaps the most beneficial safety device that has come along since seat-belts. Now we just have to make sure they function reliably in a very high percentage of all collision scenarios where they are needed.