air traffic control unit means a generic term meaning variously, area control centre, approach control unit or aerodrome control tower;
air traffic control service means a service provided for the purpose of:
Traffic control signal means a device, whether manually, electrically, or mechanically operated, by which traffic is alternately directed to stop and permitted to proceed.
Traffic control device means a flagger, sign, signal, marking, or other device used to regulate, warn or guide traffic, placed on, over, or adjacent to a street, highway, private road open to public travel, pedestrian facility, or shared-use path by authority of a public agency or official having jurisdiction, or, in the case of a private road open to public travel, by authority of the private owner or private official having jurisdiction.
Official traffic-control devices means all signs, signals, markings, and devices not inconsistent with this chapter placed or erected by authority of a public body or official having jurisdiction, for the purpose of regulating, warning, or guiding traffic.