High security bollards are impact-tested in accordance with one or more of three major crash test ratings for vehicle barriers . These are PAS 68 ( UK ) , IWA-14 ( International ) and ASTM ( US ) . Such bollards are used for hostile vehicle mitigation and are designed to protect against potential vehicle borne improvised explosive devices ( VBIED ) and vehicle as a weapon ( VAW ) attacks such as those seen in the Nice attack in 2016 and the Westminster Bridge attack in 2017
Westminster Bridge attack
2017 Westminster attack
Bollard