Part 6Vehicle configuration and dimensions

Part 6—Vehicle configuration and dimensions This Part sets out various requirements covering the suspension on vehicles and size limits for single vehicles and combinations of vehicles, so that they can be operated safely with other traffic, without taking up too much road space or damaging the road and structures on the road. Generally, the limits in this Part apply to a vehicle and any load it may be carrying. Specific requirements for loaded vehicles are covered by other laws. Division 1—Axles 58—Axle configuration (1) A motor vehicle must have only— (a) 1 axle group, or single axle, towards the front of the vehicle; and (b) 1 axle group, or single axle, towards the rear of the vehicle. (2) A trailer must have only— (a) 1 axle group or single axle; or (b) 2 axle groups, 2 single axles, or 1 axle group and single axle, in the following configuration: (i) 1 axle group, or single axle, towards the front of the vehicle, with all the wheels on the axle group or single axle connected to the steering mechanism for that part of the trailer; (ii) 1 axle group, or single axle, towards the rear of the vehicle. (3) A semi‑trailer that is extendible, or is fitted with sliding axles, must— (a) have a securing device that— (i) can securely fix the extendible part or sliding axles to the rest of the vehicle in any position of adjustment provided; and (ii) is located in a position that can prevent accidental or inadvertent release, if the device is mounted on the chassis of the vehicle; and (iii) is fitted with a visible or audible warning system to indicate to a person standing beside the vehicle that the device is not engaged; and (iv) is fitted with a way of preventing loss of air from the air brake supply, if the device uses air from the brake system and fails in a way allowing air to escape; and (v) is held in the applied position by direct mechanical action without the intervention of an electric, hydraulic or pneumatic device; and (b) be built so the adjustable parts of the vehicle remain connected if the securing device fails. 59—Retractable axles retractable axle means an axle with a means of adjustment enabling the axle to be raised or lowered relative to the other axles in the axle group. (2) For the Light Vehicle Standards, a retractable axle is taken to be an axle only when the retractable axle is in the lowered position. Division 2—Dimension requirements 60—Meaning of rear overhang and rear overhang line (1) The rear overhang of a vehicle is the distance between the rear of the vehicle and the rear overhang line of the vehicle. (2) For a vehicle with an axle group at the rear consisting of only 1 axle, the rear overhang line is a line running along the centre line of the axle. (3) For a vehicle with an axle group at the rear consisting of 2 axles, 1 of which is fitted with twice the number of tyres as the other, the rear overhang line is a line running parallel to the axles that is— (a) closer to the axle carrying the greater number of tyres than the line is to the other axle; and (b) located at one‑third of the distance between the 2 axles. (4) For a vehicle with an axle group at the rear that is not an axle group mentioned in subrule (2) or (3), the rear overhang line is a line running parallel to the axles down the centre of the axle group. (5) For the purposes of applying subrule (2), (3) or (4) to a vehicle, if an axle group includes at least 1 steerable axle, that axle is to be disregarded unless— (a) the group consists of only 1 axle and that axle is a steerable axle; or (b) all the axles in the group are steerable axles. Examples of rear overhang line—