Section 93 of the Principal Act is hereby amended -

(a) by the substitution of the following paragraph for subsection (1)(a):

"(a) A road authority, railway or canal company or other person liable to maintain a bridge carrying a public road may, by notices in the prescribed form placed in the prescribed manner on the approaches to the bridge, prohibit any vehicle or combination of vehicles which, or any part of which, transmits to the surface of that road a weight exceeding that specified in the notice in relation to such a vehicle or combination of vehicles or any part of such a vehicle or combination, from passing over that bridge either (as may be specified in the notices) at all, at a speed exceeding a specified speed or save on compliance with specified conditions.",

(b) by the insertion of the following paragraph after subsection (1)(b):

"(c) The reference in this subsection to a weight transmitted to the surface of a road by a vehicle or combination of vehicles shall be construed as a reference to the weight of such vehicle or combination, together with the weight of its load (if any), when such vehicle or combination is stationary, and the reference in this subsection to a weight transmitted to the surface of a road by any part of a vehicle or combination of vehicles shall be construed accordingly.", and