Subject to subsections (2) to (4) below, where any regulations under section 40 of this Act contain provisions varying the requirements as regards the construction or weight of any class of vehicles, provision shall be made by the regulations for exempting for such period, not being less than five years, as may be specified therein from the provisions aforesaid any vehicle of that class registered under the Vehicles (Excise) Act 1971 before the expiration of one year from the making of the regulations.
No such provision contained in regulations under the said section 40 as imposes or varies requirements with respect to the braking systems with which motor vehicles must be equipped shall be taken, for the purposes of subsection (1) above or of any other provision of the regulations, to be one relating to the construction of vehicles.
Where regulations under the said section 40 contain provisions varying the requirements as regards the construction or weight of any class of vehicle, and the Secretary of State is satisfied—
(a) that it is requisite that those provisions shall apply at a date specified in the regulations to vehicles registered before the expiration of one year from the making of the regulations, or to such of them as are specified in the regulations, and
(b) that, notwithstanding that those provisions will then apply to those vehicles, no undue hardship or inconvenience will be caused thereby,
then, if the regulations state that the Secretary of State is so satisfied, subsection (1) above shall not apply in relation to the said provisions.
Subsection (1) above shall not apply in relation to regulations made with respect to any description of weight of goods vehicles, other than their maximum unladen weight, or in relation to regulations made by virtue of subsection (2) of the said section 40.