A special road to be provided by the Minister in pursuance of a scheme under section 16 above shall, except so far as it is provided by means of the appropriation or transfer of a highway, become a trunk road on such date as may be specified in the scheme.

A highway (not being a trunk road) which, by means of an order under section 18 above, is appropriated as, or as part of, a special road to be provided by the Minister, and a highway which, by means of such an order, is transferred to the Minister, shall become a trunk road on the date on which it is so appropriated or is so transferred, as the case may be.

Subsections (1) and (2) above have effect subject to any provision of the scheme under section 16 directing that the special road in question or any part of it shall not be a trunk road.

Any such provision does not affect the power of the Minister to make an order under section 10(2)(a) with respect to the special road or part.