Aluminium in cast, extruded and plate forms is being increasingly used for a diverse range of exterior balustrade and parapet applications, particularly on bridges. There are a number of reasons for this. The metal has a high strength-to-weight ratio, it is very durable and may be safely left for many years without painting or applying a protective coating, and it has a high energy-absorption coefficient. These advantages combine to make aluminium an acceptable and frequently preferred alternative to steel for many locations where safety barriers, either for pedestrians or traffic, are required.