Heavy Vehicle (Vehicle Standards) National Regulation

A heavy motor vehicle, other than an articulated bus, must have only—

1 axle group, or a single axle, towards the front of the vehicle; and

1 axle group, or a single axle, towards the rear of the vehicle.

A heavy motor vehicle that is an articulated bus must have only—

on its front section—

1 axle group, or a single axle, towards the front of the section; and

1 axle group, or a single axle, towards the rear of the section; and

on another section—1 axle group or single axle.

A heavy trailer must have only—

1 axle group or a single axle; or

2 axle groups, 2 single axles, or 1 axle group and a single axle, in the following configuration—

1 axle group, or a 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;

1 axle group, or a single axle, towards the rear of the vehicle.

A semitrailer that is extendible, or fitted with sliding axles, must—

have a securing device that—

can securely fix the extendible part or sliding axles to the rest of the vehicle in any position of adjustment provided; and

is located in a position that can prevent accidental or inadvertent release, if the device is mounted on the vehicle’s chassis; and

is fitted with an audible or visible warning system to indicate to a person standing beside the vehicle that the device is not engaged; and

is fitted with a way of preventing loss of air from the air brake supply, if the device uses air from the semitrailer’s braking system and fails in a way allowing air to escape; and

is held in the applied position by direct mechanical action without the intervention of an electric, hydraulic or pneumatic device; and

be built so the adjustable parts of the vehicle remain connected if the securing device fails.