. The components of guardrail systems include posts, beams, fasteners, end treatments, and other accessories. Expressway guardrails typically come in sizes of W-beam, Thrie-beam, and box beams. These guardrails are usually available in lengths of 6m, 9m, 12m, and 15m and are also available in different widths, depending on the type of guardrail. W-Beam guardrails have a basic design shape of two waves, while Thrie-beam guardrails have three waves. Box beams are composed of two flat pieces of she