A set of Interstate Highways serving Oʻahu were authorized by the federal government in 1960, a year after Hawaii was admitted as a state. One of the corridors, connecting Barbers Point to Diamond Head, was designated as H-1 by the Bureau of Public Roads (now the Federal Highway Administration) on August 29, 1960. The portion of H-1 that runs through Downtown Honolulu had opened in 1953 as the Mauka Arterial and was incorporated into the new freeway. This section has been largely unchanged since its inception and its design suffers from having too many on/offramps, short distanced onramps, and onramps that enter the freeway almost immediately before an offramp (opposite of current design standards). The 'new' section of H-1 was, however, built to modern freeway standards.
