In this Act -
the expression "the Minister" means the Minister for Local Government and Public Health;
the expression "the Commissioner" means the Commissioner of the Gárda Síochána;
the word "vehicle" includes every kind of carriage, conveyance, or machine, however propelled or drawn, which is constructed or adapted for use on roads or on permanent rails laid on roads, whether such carriage, conveyance, or machine is supported on wheels, rollers, moving track, or sliding runners, and whether such carriage, conveyance, or machine is or is not used or capable of being used for the carriage of persons or of goods, but the said word does not include any carriage or conveyance which is carried and wholly supported by human beings or animals;
the expression "mechanically propelled vehicle" does not include a tramcar or other vehicle running on permanent rails;
the expression "public service vehicle" means a mechanically propelled vehicle used for the carriage of passengers for rewar