Overdimension vehicles and loads need to follow additional requirements before travelling on our roads.

This is so they can travel on the road safely – for example, get around corners and fit under bridges. The maximum dimensions for vehicles are set out in Land Transport Rule: Vehicle Dimensions and Mass Rule 2016 (VDAM Rule).

Land Transport Rule: Vehicle Dimensions and Mass 2016

This commonly includes vehicles used in house relocation.  If your vehicle or load exceeds dimension limits, you may need to apply for an overdimension permit before you travel.

If your vehicle or load is also overweight, you will also require an overweight permit.

Overweight permits

What is an overdimension vehicle or load?

An overdimension (or oversize) vehicle or load is one that exceeds one or more of the maximum dimensions allowed for standard vehicles. To operate an overdimension vehicle or load, you may need an overdimension permit.

Overdimension vehicles or loads are only allowed to operate on an overdimension permit if they are indivisible. (An indivisible load is a load that without an unreasonable amount of effort or expense, or the risk of damage to the load, can't be divided into two or more sections for road transport.) If your load is divisible and within general access limits, please contact the Freight & Register Records team for your options on 0800 683 774.

Construction machinery that is carried on an overdimension permit should be loaded so it fits within standard dimension limits, if possible.

Is my vehicle or trailer overdimension?

Check to see if:

What are the requirements for overdimension vehicles and loads?

The standard dimensions of vehicles, loads and how much loads can overhang are set by law in the Vehicle Dimensions and Mass Rule. However, the rule also provides for occasions when loads and vehicles exceed the standard limits.

There are four categories of overdimension vehicles and loads. In some cases you must apply to us for an overdimension permit which sets a number of requirements, including:

  • pre-travel route checks
  • required permissions, eg from railway operators
  • vehicle lighting
  • piloting
  • emergency service notifications.

Types of overdimension vehicles and loads

Overdimension operating requirements

Changes to Categories under the VDAM Rule 2016

Category 4 and Category 5 have changed to Categories 4A and 4B respectively.

Vehicles and loads that previously operated under Category 3 requirements may now need to operate under Category 4B requirements.

To determine your category see Types of overdimension vehicles and loads 

There are specific operating requirements for the revised Categories 4A and 4B that are different under VDAM Rule 2016. 

The new requirements are detailed in Part C3.1 of the Permit Manual. These include travel times and piloting.  You may also need to obtain an engineering assessment.

Engineering assessment requirements for Category 4B

Due to the size and impact of Category 4B vehicles, an engineering assessment prepared by a chartered professional engineer is required as part of the permit application process. These requirements are detailed in Part C5.5 of the Permit Manual.

We suggest you work with your engineer to ensure the assessment meets requirements as incomplete assessments may be returned to you for correction. This may delay your application.

Want to get an overdimension permit?

The overdimension application form was updated on 1 February 2017 and contains new criteria for Categories 4A and 4B. Any applications using an old form or not fully completed will be returned to the submitter.

You can apply for an overdimension permit using the online form.

Application for an overdimension permit

Simply fill in your details and the details of your overdimension vehicle or load, complete the extra requirements if your load is category 4A or 4B, add any attachments, complete the declaration and submit your application.

Processing times

We will endeavour to process your application within two days so please ensure you submit your application in advance.

Urgent applications (genuinely unplanned and required last minute) will be processed on special request and we will call you if we have any questions.

Operator checks

Please note that all overdimension applications undergo an Operator Check, taking into consideration traffic offence history and permit breaches. Where there are no issues, this generally only takes 5 minutes to complete and will not impact the turnaround time for your application.  If there are issues we will contact you.

Driving overdimension vehicles

Requirements and restrictions you need to know about when driving an overdimension vehicle

Roles, responsibilities and permit restrictions for overdimension vehicles

Overdimension travel time restrictions(external link).

Load pilots

You may also have to engage one or more suitably qualified load pilots to supervise the journey. There are two classes of load pilots, each requiring different levels of training.

Requirements for pilots in the Load pilot code

High-productivity motor vehicles

If you want to carry divisible loads such as logs, milk powder or freight more productively, you may be able to operate on a high-productivity motor vehicle permit.

High-productivity motor vehicle permits

Bridge engineering self-supervision (BESS)

Drivers of heavy vehicles can be registered and approved to self-supervise crossings on certain bridges which would normally be supervised by an engineer – this is called bridge engineering self-supervision (BESS).

Find out more about BESS and how to apply

Exemption from Vehicle Dimension and Mass Rule requirements

If you need an operational exemption from Vehicle Dimension and Mass Rule Requirements, please complete our exemption application form.

Apply for an exemption from the Vehicle Dimension and Mass Rule requirements