The Malaysian Expressway System (Malay: Sistem Lebuh Raya Ekspres Malaysia) is a network of national controlled-access expressways in Malaysia that forms the primary backbone network of Malaysian national highways. The network begins with the Tanjung Malim–Slim River tolled road (Federal Route 1) which was opened to traffic on 16 March 1966, later North–South Expressway (NSE), and is being substantially developed. Malaysian expressways are built by private companies under the supervision of the government highway authority, Malaysian Highway Authority (abbreviated as MHA; also referred to as Lembaga Lebuhraya Malaysia (LLM) in Malay).