The director may designate demonstration sections of other portions of highways as high occupancy vehicle lanes by the installation of official traffic control devices when deemed necessary to improve traffic conditions. Designated demonstration sections may be in operation for a period not to exceed one calendar year. In order to make a demonstration section effective beyond the one year period, the demonstration section must be designated as a high occupancy vehicle lane by an amendment of section 19-108-4
Haw. Code R. § 19-108-5