In this Act "motor car" means a mechanically propelled vehicle, not being a motor cycle or an invalid carriage, which is constructed itself to carry a load or passengers and the weight of which unladen—
In this Act " heavy motor car" means a mechanically propelled vehicle, not being a motor car, which is constructed itself to carry a load or passengers and the weight of which unladen exceeds two tons and a half.
In this Act " motor cycle " means a mechanically propelled vehicle, not being an invalid carriage, with less than four wheels and the weight of which unladen does not exceed eight hundredweight.
In this Act " invalid carriage " means a mechanically propelled vehicle the weight of which unladen does not exceed five hundredweight and which is specially designed and constructed, and not merely adapted, for the use of a person suffering from some physical defect or disability and is used solely by such a person.
In this Act " motor tractor " means a mechanically propelled vehicle which is not constructed itself to carry a load, other than the following articles, that is to say, water, fuel, accumulators and other equipment used for the purpose of propulsion, loose tools and loose equipment, and the weight of which unladen does not exceed seven tons and a quarter.
In this Act " light locomotive" means a mechanically propelled vehicle which is not constructed itself to carry a load, other than any of the articles aforesaid, and the weight of which unladen does not exceed eleven tons and a half but does exceed seven tons and a quarter.
In this Act " heavy locomotive " means a mechanically propelled vehicle which is not constructed itself to carry a load, other than any of the articles aforesaid, and the weight of which unladen exceeds eleven tons and a half.
For the purposes of this section, in a case where a motor vehicle is so constructed that a trailer may by partial super-imposition be attached to the vehicle in such a manner as to cause a substantial part of the weight of the trailer to be borne by the vehicle, that vehicle shall be deemed to be a vehicle itself constructed to carry a load.
For the purposes of this section, in the case of a motor vehicle fitted with a crane, dynamo, welding plant or other special appliance or apparatus which is a permanent or essentially permanent fixture, the appliance or apparatus shall not be deemed to constitute a load or goods or burden of any description, but shall be deemed to form part of the vehicle.
The Secretary of State may by regulations vary any of the maximum or minimum weights specified in the foregoing provisions of this section, and such regulations may have effect either generally or in the case of vehicles of any class specified in the regulations and either for the purposes of this Act except sections 68 to 81 and of all regulations thereunder or for such of those purposes as may be so specified ; and nothing in section 78 of the Road Traffic Regulation Act 1967 shall be construed as limiting the powers conferred by this subsection.