Haw. Code R. § 19-103-17
The display of official notices and signs posted by order of any court or public office, or posted by any public officer within his territorial or zoning jurisdiction in the performance of a public duty, or posted by any person required to do so by any statute or ordinance or regulation having the force of law shall not be considered as outdoor advertising and shall be permitted. A sign for a town approved and authorized by the county may be considered an official sign. The sign shall contain only the name of the town and its logo, if any. Historical markers erected by state, a county or a nonprofit historical society shall be considered official signs. The design of the markers shall be approved by the state department of planning and economic development.
Haw. Code R. § 19-103-17