Route numbers have been allocated to roads in New South Wales since 1955. To supplement the national route number system, three "ring roads" were built in Sydney in 1964. These were numbered 1, 3 and 5. In 1973, a system of numbering freeways was introduced to New South Wales to complement the national routes and ring roads. In 1974, the National Highway network was defined, which in New South Wales included the Hume Highway, Federal Highway, Barton Highway, Sydney-Newcastle Freeway (now Pacific Motorway) and New England Highway. In 1993, Sydney's Metroad system was introduced.