Haw. Code R. § 19-108-2
As used in this chapter: "Bus" means every motor vehicle designed for carrying more than ten passengers and used for the other than a school bus or a taxicab, designed and used for the transportation of persons for compensation.
"Demonstration section" means a section of roadway used as an experimental project for improvements to validate cost-benefits.
"Department" means state department of transportation.
"Director" means state director of transportation or an authorized representative.
"Driver" means every person who drives or is in actual physical control of a vehicle.
"Electric Vehicle" means a vehicle as defined in § 291-71, HRS.
"Emergency vehicle" includes such fire department vehicles, police vehicles, ambulances, and ocean safety vehicles as are publicly owned and such other publicly or privately owned vehicles as are designated by the city or county council.
"Express lane" means a rapid travel lane and may include high occupancy vehicle lanes.
"High occupancy vehicle" means a motor vehicle carrying at least two or more persons, including carpools, vanpools, and buses.
"High occupancy vehicle lane" means a designated lane of a laned roadway where the use of the designated lane is restricted to school buses, vehicles carrying at least two persons, and other vehicles as provided herein or by county ordinance.
"Motorcycle" means every motor vehicle having a seat or saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground but excludes a farm tractor and a moped.
"Official traffic-control devices" means all signs, signals, markings, and devices not inconsistent with this chapter placed or erected by authority of the director, for the purpose of regulating, warning, or guiding traffic.
"Police Officer" means every officer authorized to direct or regulate traffic or to make arrests for violations of traffic regulations.
"Public transit bus" means a bus used in the county bus system and owned by the county or a contractor with the county.
"School bus" means every motor vehicle as defined in § 286-181, HRS, and any rules promulgated pursuant to that section by the department of education.
"Zip or zipper lane" means a barrier-separated high occupancy vehicle lane.
Haw. Code R. § 19-108-2