Driving tests

Vehicle dimensions and mass (VDAM) changes

This is the essence of the new Vehicle Dimensions and Mass 2016 rule and it saves you reading the whole document:

It replaces the 2002 VDAM rule and came into effect on 1 February 2017. If you need to know how to calculate the maximum legal axle weights for your truck, this course will show you how.

Weight changes

On permitted roads, the following new weights apply for HPMV:

  • 7-axle combinations with a minimum wheelbase of 16.8m can now be 45,000kg (up from 44,000kg)
  • 8-axle combinations with a minimum wheelbase of 17.4m can now be 46,000kg (up from 44,000kg)
  • Simple trailers: an additional 4000kg gross mass to approved trailers, now 40,000kg up from 36,000kg.

Minimum lengths ensure loads are spread out to accommodate bridge loading limits.

There is no change to any other vehicles, and this new rule does not affect High Productivity Motor Vehicles (HPMVs).

You need a permit to run on roads not on the map, and you will still need a permit for some roads for a 50MAX vehicle.

Width changes

  • The maximum width (excluding mirrors, aerodynamic devices and close-proximity monitoring systems) before you need an oversized load permit is 2.55m including load securing devices (previously it was 2.5m plus load securing devices).
  • The maximum width including mirrors is 2.98m.
  • Aerodynamic devices can be 25mm either side.
  • CPMS can be 70mm either side.

Height changes

The maximum height is now 4.3m including load securing devices (previously it was 4.25m plus load securing devices).

There are certain exceptions where technology allows the vehicle to temporarily exceed this height when raising the vehicle to clear obstacles.

Weighing tolerances

Tolerances have been reduced to:

  • 500kg for all individual axles and gross mass limits (down from 1500kg)
  • 1000kg for axle sets (e.g. a tri-axle set at the rear of a semi-trailer) other than steer axles.
  • There’s a proposal before Parliament to change tolerances to a percentage-based system.

Vehicle compliance and permits

If your vehicle was compliant and legal before the changes, it will still be compliant.

If you have a permit issued before February 1, it’s still valid.

Desired outcomes of the changes

  • Fewer vehicles on the road
  • Fewer trips required
  • Better efficiency
  • Wider choice of vehicles for freight and bus companies

If you want to get into the detail of the changes, they are explained here.

You can read more about vehicle weights and mass here.

Darren has written over 3000 articles about driving and vehicles, plus almost 500 vehicle reviews and numerous driving courses. Connect with him on LinkedIn by clicking the name above

Posted in Advice, Heavy Vehicle