Ideas about forces and energy to explain advances in road safety?

Question

Ideas about forces and energy to explain advances in road safety?

Answer 1

One example is flexible barriers between the two directions of lanes.  When people crash into them, they "flex" and spread out the time over which energy is absorbed.  It makes the crash much less significant.  They even use them at racetracks.

Another one in daily use is the barrels of sand or water at each freeway off ramp that are where the two sperate.  That way if someone crashes, they will not just run straight into metal or concrete and will have a less serious accident in terms of injury and fatalities.