Guardrail

A highway guardrail is a barrier, most often fabricated steel in a box-beam or W-beam profile, installed along a roadside to stop an errant vehicle before it strikes a fixed hazard such as a utility pole or tree, runs down a steep embankment, or crosses into oncoming traffic. The American Rolling Mill Company, known as Armco, developed the steel highway guardrail still recognizable today in 1933, and a separate steel rail aimed at agricultural use followed from Kee Clamp Steel in 1934; in 2001 the British company A-SAFE introduced the first fixed but flexible polymer guardrail, built from materials such as polyethylene, polypropylene or PVC, aimed initially at industrial rather than highway use. The underlying goal across every material has stayed the same: absorb or redirect the energy of an impact rather than simply blocking it outright.