(1) Mechanically propelled vehicles shall, for the purposes of this Act, be divided into four classes, namely, motor cycles, light motor vehicles, heavy motor vehicles, and locomotives.
(2) For the purposes of this Act a mechanically propelled vehicle shall be a motor-cycle if and whenever and so long as it complies with all the following conditions, that is to say: -
(a) it does not exceed eight hundredweight in weight unladen; and
(b) it is supported exclusively by wheels in direct contact with the ground; and
(c) it has not more than three wheels; and
(d) it has all its wheels fitted with pneumatic tyres.
(3) For the purposes of this Act a mechanically propelled vehicle shall be a light motor vehicle if and whenever and so long as it complies with all the following conditions, that is to say: -
(a) it is not a motor cycle; and
(b) where it is fitted with a body designed and constructed for the carriage of passengers, it does not exceed three tons in weight unladen or, where eit