Q Could you please define a "motor tractor " ? How does this differ from an artic tractive unit ?
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A According to Section 190 (6) of the Road Traffic Act 1972, a motor tractor is a mechanically propelled vehicle which is not constructed itself to carry a load other than 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 71/4 tons.
If the unladen weight exceeded 71/4 tons then it would become a light locomotive and if it exceeded 11i tons then it would be a heavy locomotive.
Subsection (9) of Section 190 states that where a motor vehicle is so constructed that a trailer may by partial superimposition be attached to the vehicle in such a manner as to cause a substantial part of the trailer to be borne by the vehicle (in other words an artic tractive unit) that vehicle shall be deemed to be a vehicle itself constructed to carry a load. Thus, because an artic tractive unit is a vehicle constructed to carry a load, it cannot be a "motor tractor."