Principle of Road-Safety barriers

Unsafe, Safety Crash Barriers

Who, or what, are Crash-Barriers designed  to protect?    We are not talking about crash-barriers on Motorways here, but crash barriers on normal "A" roads, or lesser roads.

This barrier (adjacent to an "A" road) offers a degree of protection for pedestrians and cyclists from motor vehicles that might have got out of control, though I fancy it was installed mainly to protect the lamp-posts. [Romney Marsh Road A2042, Ashford].

Whereas this barrier might well prevent out-of-control vehicles from going down an embankment, it actually places pedestrians and cyclists in greater danger, they could be crushed against the barrier by an errant vehicle.   Why wasn't the barrier placed next to the kerb?  Had it been, then pedestrians and cyclists would have a degree of protection, without adversely affecting the safety of motor-vehicles.   There should not be any significant difference in the cost, if any at all.  [Simone-Weil Avenue Ashford]

This is a typical example of how it should be done (on both sides of this road), as seen in Germany. It is protecting pedestrians, cyclists (shared use), and motorists.