9. (1) The length of a vehicle together with any equipment or load being carried by it shall not exceed—
(a) in the case of a non-articulated vehicle other than a bus—11 metres;
(b) in the case of a non-articulated bus that has a twin-steer axle group and another tandem axle group—12.8 metres;
(c) in the case of a non-articulated bus, not being a bus referred to in paragraph (b)—12.2 metres;
(d) in the case of an articulated bus—18 metres;
(e) in the case of an articulated vehicle other than a bus—17.5 metres; or
(f) in the case of a vehicle comprising a motor vehicle and one or more trailers—17.5 metres.
(2) A reference in paragraph (1) (f) to a trailer does not include a reference to a semi-trailer.