Haw. Rev. Stat. § 264-6: State highway not to be disturbed without permit.

No person or government agency, whether federal, state, or county, shall, in any manner or for any purpose do any of the following acts without a written permit from the director of transportation or the director's authorized representative:

(1) Break up, dig up, disturb, undermine or dig under, or cause to be broken up, dug up, disturbed, undermined, or dug under, the right-of-way of any state highway; or

(2) Place, erect, leave, or store any structure, motor or other vehicle, equipment, or any other object wholly or partially within the right-of-way of any state highway; provided that this paragraph shall not apply to the holding or displaying of movable signs, for the purpose of carrying on political campaign activities.