The current state (then territorial) highway numbering system was established in 1955. Route numbers are organized so that the initial digit corresponds to the island: • Numbers beginning with 1 or 2:
Hawaiʻi • Numbers beginning with 3:
Maui • Numbers beginning with 4:
Molokai,
Lanai • Numbers beginning with 5:
Kauai • Numbers beginning with 6 to 9:
Oahu In general, two-digit numbers are primary highways, maintained by the state. Three-digit routes are typically secondary arterials or collectors, while four-digit routes are typically collectors and minor roads. For secondary routes, the first two digits generally relate to the associated primary route. Many secondary routes are county-maintained and unsigned, their route numbers being used merely by state agencies as an asset-tracking measure. When referring to highways, Hawaiʻi residents usually refer to state highways by their names instead of their route numbers (e.g.
Kamehameha Highway instead of
Route 99). Note that one named highway may encompass several route numbers (e.g. Kamehameha Highway, which carries Routes 80, 83, 99, and 830 at various points along its length) and vice versa. ==Numbered county routes==