31.—(1) In Article 30 “heavy commercial vehicle” means any goods vehicle which has an operating weight exceeding 7.5 tonnes.
(2) The operating weight of a goods vehicle for the purposes of this Article is
(a)in the case of a motor vehicle not drawing a trailer or in the case of a trailer, its maximum laden weight;
(b)in the case of an articulated vehicle, its maximum laden weight (if it has one) and otherwise the aggregate maximum laden weight of all the individual vehicles forming part of that articulated vehicle; and
(c)in the case of a motor vehicle (other than an articulated vehicle) drawing one or more trailers, the aggregate maximum laden weight of the motor vehicle and the trailer or trailers attached to it.
(3) In this Article “articulated vehicle” means a motor vehicle with a trailer so attached to it as to be partially superimposed upon it; and references to the maximum laden weight of a vehicle are references to the total laden weight which must not be exceeded in the case of that vehicle if it is to be used in Northern Ireland without contravening any regulations for the time being in force under Article 55.
(4) In this Article, and in the definition of “goods vehicle” in Article 2(2) as it applies for the purposes of this Article, “trailer” means any vehicle other than a motor vehicle.
(5) The Department may by regulations amend paragraphs (1) and (2) (whether as originally enacted or as previously amended under this paragraph)—
(a)by substituting weights of a different description for any of the weights there mentioned;
(b)in the case of paragraph (1), by substituting a weight of a different description or amount, or a weight different both in description and amount, for the weight there mentioned.
(6) Without prejudice to section 17(5) of the Interpretation Act (Northern Ireland) 1954(1), different regulations may be made under paragraph (5) as respects different classes of vehicles or as respects the same class of vehicles in different circumstances and as respects different times of the day or night and as respects different localities.
(7) Regulations under paragraph (5) shall not so amend paragraph (1) that there is any case in which a goods vehicle whose operating weight (ascertained in accordance with paragraph (2) as originally enacted) does not exceed 7.5 tonnes is a heavy commercial vehicle for any of the purposes of Article 30.