New Vehicle Dimensions and Mass (VDAM) rules now in effect


Changes in gross mass rules and bridge weight restrictions for heavy vehicles, included as part of the 2016 Vehicle Dimensions and Mass (VDAM) Rule, came into full effect from Friday 1 December 2017.

The main changes are as follows: 

Combination size

Minimum wheelbase length

New allowable Gross Mass

7-Axle combinations

16.8 metres

45 tonne (was 44t)

8-Axle combinations

17.4 metres

46 tonne (was 44t)

There are some existing bridges in New Zealand that were able to carry the 44 tonne gross mass but are not suitable for increased loads. These bridges will be signposted as 44 tonne and are shown on the 50MAX book of maps: link)

There are also bridges on New Zealand roads that have restrictions below 44 tonne. Information about these bridges will need to be obtained from the relevant local Road Controlling Authority, i.e. the NZ Transport Agency if a state highway road; otherwise the local council. 

Queries about bridges on the state highway network can be directed to 0800 699 000.

Questions about bridges on local roads should be directed to the relevant council or other Road Controlling Authority.