In sections 36 to 39 of this Act—

• " authorised " means specially authorised by the Secretary of State ;

• " motor vehicle " has the same meaning as in the [1984 c. 27.] Road Traffic Regulation Act 1984 ;

• “ road hump " means an artificial hump which is in, or on the surface of, a road and which is designed to control the speed of vehicles; and references to a road hump include references to any other works (including signs or lighting) required in connection with such a hump; and

• " statutory", in relation to a speed limit, means having effect by virtue of an enactment.