Certification of cab modifications

One of the responsibilities Waka Kotahi NZ Transport Agency has as the regulator of land transport is to ensure that vehicles on New Zealand roads are safe, including after any vehicle modifications or repairs that are undertaken. The cab of a vehicle is designed by manufacturers to protect those sitting within it and any changes made to the cab can increase the risk to occupant safety.

Since the early 2000s, cab modifications have been required by the various land transport rules and regulations to be certified, to ensure the cabs remain within safe tolerance of their state when manufactured. There have been no new Land Transport Rules introduced for cab modifications of heavy vehicles, including motorhomes and horse trucks. However, over the years, requirements have been applied inconsistently, resulting in some vehicles being modified correctly and others not. This meant that recently, some vehicles were required to undertake retrospective certification.

To address this ambiguity, a recommendations memo was submitted at the end of September 2021 for consideration by Senior Management.

Waka Kotahi has approved the following:

• Provide short-term relief to vehicle owners now by granting a class exemption for all vehicles that have had uncertified cab modifications carried out before November 2018.
• The initial class exemption is for five years and applies from 6 October 2021 to vehicles over 3.5 tonne.
• The initial class exemption expires at the end of 30 September 2026 and may be amended, replaced, or revoked in accordance with section 168E(2) of the Land Transport Act 1998.

This means that people with vehicles granted the exemption can continue using their vehicle and obtain a Certificate of Fitness (CoF) for the duration of the exemption.

Vehicle inspectors are still required to check cab modifications as part of the standard CoF test. If they have any safety concerns (e.g. deformation, cracking, damage), they may refer the vehicle to a specialist certifier as part of their standard inspection practice.

The exemption is applied automatically and vehicle owners are not required to do anything.

Please note that since November 2018 certification of cab modifications has been a requirement of the Vehicle Inspection Requirements Manual and modifications carried out since this date should have been certified. This includes imported vehicles with cab modifications registered for the first time in NZ since this date that don’t have recognised overseas certification.

Waka Kotahi is currently developing a Code of Practice (CoP) with industry experts to provide clear guidelines for the certification of cab modifications.

Certification of cab modifications recommendations memo [PDF, 1.8 MB]