Haw. Rev. Stat. § 291C-197: Driving mopeds on bicycle lanes and paths.

(a) Wherever bicycle lanes are provided on the roadway, moped drivers shall use such bicycle lanes.

(b) The director of transportation by rule and the counties by ordinance may with respect to bicycle paths under their respective jurisdictions restrict or prohibit the use of such bicycle paths by mopeds. Signs clearly visible to an ordinarily observant person indicating the restriction or prohibition shall be placed along bicycle paths so designated and every moped driver shall obey the directions thereof.

(c) This section shall not apply to a three-wheeled moped.