Submitting correct MIRO values

About this guidance

This guidance explains how regulated entities (entities) can ensure that Mass in Running Order (MIRO) data in Register of Approved Vehicles (RAV) submissions complies with requirements under the New Vehicle Efficiency Standard (NVES).

This guidance is intended to provide entities with an understanding of their legislative requirements. Entities should read it in conjunction with relevant legislation. It is not a substitute for independent legal advice.

What requirements apply to MIRO values for NVES

Entities must submit MIRO values for each covered vehicle entered on the RAV as required by the Road Vehicle Standards (Information on the Register of Approved Vehicles) Determination 2021(Opens in a new tab/window) (the Determination). Entities must ensure that all submitted vehicle data, including MIRO, is correct as required under section 8 of the Road Vehicle Standards Rules 2019(Opens in a new tab/window) (the Rules).

The definition of MIRO can be found in Australian Design Rule (ADR) 111/00(Opens in a new tab/window):

"Mass in running order" means the mass of the vehicle, with its fuel tank(s) filled to at least 90 per cent of its or their capacity/capacities, including the mass of the driver, fuel and liquids, fitted with the standard equipment in accordance with the manufacturer’s specifications and, when they are fitted, the mass of the bodywork, the cabin, the coupling and the spare wheel(s) as well as the tools.

Several elements of this definition recognise that vehicles may be supplied or tested in different configurations, particularly cab-chassis vehicles without final bodywork fitted. 

However, this flexibility is not open-ended: entities must keep evidence to support the method that has been used to determine the MIRO value declared on the RAV. Unlike carbon dioxide (CO₂) emissions values, interpolation is not permitted for MIRO. Each vehicle entered onto the RAV must have a MIRO specific to its own unique mass and characteristics.

For cab-chassis vehicles with no bodywork fitted when supplied or tested, the Determination allows the MIRO value declared on the RAV to be determined using one of the permitted cab-chassis methods. Later sections in this guidance provide more information about these exceptions from the standard definition.

Why accurate MIRO values matter

Accurate MIRO values are essential because they are used to calculate an entity's performance under the NVES. MIRO values affect the number of NVES units issued or the liability an entity may accrue if it does not beat the target.

The NVES Regulator may undertake validation and assurance activities to identify potential inconsistencies or data quality issues. However, responsibility for submitting accurate, complete and supportable MIRO data remains with the regulated entity.

Unlike CO₂, where reporting a higher value is a conservative approach, reporting a MIRO value that exceeds the configuration being provided to Australia can inadvertently advantage a vehicle's NVES position.

Definitions and references to MIRO may exist in other jurisdictions and for purposes other than NVES compliance. It is important that entities understand how MIRO is defined for NVES for RAV submissions.

How to identify and submit the correct MIRO value in RAV

Use the following 5 steps to identify and submit the correct MIRO value for vehicles covered under the NVES. Entities should still refer to the relevant legislation, ADRs and approval material when making compliance decisions.

The 5 steps are: 

1. identify the exact vehicle configuration
2. start with the base vehicle mass
3. add the required MIRO components
4. apply the cab-chassis method if relevant
5. keep records and maintain data quality.

Step 1: Identify the exact vehicle configuration

Confirm the model, variant, body style, drivetrain, standard equipment and any fitted bodywork that matches the vehicle being entered on the RAV.

Step 2: Start with the base vehicle mass

Refer to manufacturer technical data, approval documentation, test reports, weighing records or supporting information used for emissions approval to find the correct base vehicle mass.

Do not rely on a mass value from a different variant unless the supporting evidence shows that the mass and relevant characteristics are the same.

Step 3: Add the required MIRO components

Under the ADR definition, add the following components to the base vehicle mass:

• fuel tank filled to at least 90%
• driver mass (75 kg)
• fuel and operating liquids
• standard equipment
• fitted bodywork, cabin, coupling, spare wheels and tools where applicable.

MIRO is based on a vehicle’s fuel tank being filled to at least 90% of capacity, a manufacturer may calculate MIRO using 90 to 100% fuel load. Provided the fuel level is at least 90%, values within that range may be valid.

MIRO should not include passengers, payload/cargo or optional equipment unless it forms part of the standard specification or is otherwise required under the applicable method.

Step 4: Apply the cab-chassis method if relevant

For cab-chassis vehicles with no bodywork fitted when supplied or tested, the Determination allows the MIRO value declared on the RAV to be determined using one of the permitted cab-chassis methods: 

• the highest MIRO value declared in the supporting information underpinning the CO₂ value declared for the chassis-cab by the manufacturer
• the MIRO value of the chassis-cab without bodywork fitted plus the average mass of the bodywork options offered for fitment to the vehicle by the vehicle’s manufacturer
• the MIRO of the chassis-cab without bodywork fitted plus the maximum area of the body recommended for fitment to the vehicle by the vehicle’s manufacturer (in square metres to one decimal place) multiplied by 50 kg.

Step 5: Keep records and maintain data quality

Record-keeping and documentation

Entities need to document assumptions, conversions, interpolation steps or calculations that were used to derive MIRO values.

Under the Road Vehicle Standards Act 2018(Opens in a new tab/window) (RVSA), entities must ensure that information entered on the RAV, including NVES-specific data, is true and correct. Keeping up-to-date supporting information is also required under section 30 of the Rules.

Good record-keeping provides other benefits, including:

• Providing evidence to demonstrate compliance, if the NVES Regulator asks questions about data assurance.
• Supporting data integrity and consistency when staff, systems or approval arrangements change.

The following table provides examples of the types of evidence that may support the MIRO method used for a vehicle entered on the RAV. The examples do not cover every situation, and entities should keep evidence that clearly demonstrates how the declared MIRO value was determined and how it relates to the vehicle’s specific configuration.

Data quality checks

Before submitting vehicles to the RAV, entities should complete internal checks to confirm that the data is correct. This includes checking:

• model and variant identifiers are correct
• submitted MIRO value matches supporting technical material
• MIRO value is reasonable when compared with the vehicle’s tare mass and Gross Vehicle Mass (GVM) to identify potential errors, as these values are commonly confused
• each model variant has a distinct MIRO value that reflects its motive power, engine size and factory-standard accessories.

Entities may also choose to engage an audit provider or conduct independent internal assurance to test data quality and identify areas for improvement. This is not mandatory, but it can improve confidence in the accuracy, completeness and traceability of the data that underpins NVES compliance.

Difference between MIRO, tare mass and GVM

The following table explains practical difference between MIRO, tare mass and GVM. 

For NVES and RAV purposes, entities should use the MIRO value required under the applicable NVES and ADR requirements, rather than relying on tare mass or GVM.

When to contact us

If you have questions or concerns about the correct basis for MIRO values, we encourage you to contact us before vehicles are entered on the RAV. Contacting us early can reduce delays and avoid the need to correct RAV entries later.

Downloadable versions of the guidance

• Submitting correct MIRO values (Word 266 KB)
• Submitting correct MIRO values (PDF 249 KB)

Scenario: Impact of MIRO on NVES emissions targets  

The NVES does not apply a single emissions target to all vehicles. Instead, each covered vehicle is assigned a vehicle‑specific emissions target that is adjusted for mass, using the vehicle’s MIRO (per ADR 111/00(Opens in a new tab/window)) recorded on the RAV. 

MIRO refers to the vehicle’s mass when ready for use. This includes a driver, fuel (at least 90% full), all operating fluids, standard manufacturer‑specified equipment, and any fitted bodywork, cabin, coupling, spare wheels, and tools.

Differences in MIRO between vehicle variants, such as those arising from powertrain or body style, can affect the emissions target of each variant. 

Scenario: Bottle Brush Motors

This scenario focuses on 2 variants of a fictional vehicle model to demonstrate how the MIRO affects a vehicle’s emissions target. 

Bottle Brush Motors holds a Vehicle Type Approval for the Divinity, a Type 2 (Light Goods Vehicle, NA) ute with 2 variants:

• The Base variant of the Divinity is fitted with a single cab, resulting in a lower MIRO.
• The Wattle variant of the Divinity is fitted with a dual cab, resulting in a higher MIRO. 

Here’s what was entered on the RAV in 2026: 

Emissions target calculation

Using the formula below, we can calculate the emissions target for the Divinity variants. Once we have the emissions target, we can compare it with the vehicle’s CO₂ emissions number.

Emissions target: HL+MAF (DM−RM)

Where:

• HL is the Headline Limit. For a Type 2 vehicle in 2026 this is 180. 
• MAF is the Mass Adjustment Factor. For a Type 2 vehicle in 2026 this is 0.0324.
• DM is the Designated MIRO. For a Type 2 vehicle with a MIRO of over 1500 kg and under 2400 kg, this will be the MIRO number entered on the RAV (subject to the application of lower and upper breakpoints under the NVES). 
• RM is the Reference MIRO. For a Type 2 vehicle in 2026 this is 2155.

The emissions target for the Divinity – Base variant is:

180 + 0.0324 x (2220 − 2155) = 182.1060

Therefore, the emissions target for the Base variant is 182.1060 g/km, meaning the vehicle’s CO₂ emissions number exceeds its target by 97.8940 g/km.

The emissions target for the Divinity – Wattle variant is:

180 + 0.0324 × (2280 − 2155) = 184.0500 

The emissions target for the Wattle variant is 184.0500 g/km, meaning the vehicle’s CO₂ emissions number exceeds its target by 95.9500 g/km.

Although both variants share the same CO₂ emissions number, the heavier Wattle variant has a higher emissions target due to its greater MIRO. As a result, the Wattle variant exceeds its emissions target by a smaller margin than the Divinity’s Base variant. 

This scenario illustrates how a higher MIRO can increase a vehicle’s emissions target.

This is a fictional scenario and is not based on any real regulated entity or vehicle.