Of all the materials used for bridges over the centuries, stainless steel will likely prove the most effective and durable. Europe led the way in using duplex grades, though some use was also made of austenitics. In the USA, a ferritic-martensitic dual-phase grade has found favor, but duplex grades are being assessed and more frequently applied. Among the reasons for this are the excellent mechanical properties of duplex, its corrosion resistance, and its favorable strength-to-weight ratio.