Road routes in Victoria assist drivers navigating roads throughout the state, as roads may change names several times between destinations, or have a second local name in addition to a primary name. There are two main route numbering schemes in use: numeric shields, and alphanumeric routes, with the former being replaced by the latter. The original scheme consists of numbered National Highways, National Routes, Metropolitan and State Routes, each identified with a different shield-shaped route marker. The alphanumeric Statewide Route Numbering Scheme, introduced in the 1990s, has replaced the previous scheme outside Melbourne, and some routes within Melbourne. It consists of alphanumeric routes, which are a one-to-three digit number prefixed with a letter – M, A, B, or C – that denotes the