If you used powered auxiliary equipment in a heavy vehicle but your vehicle isn't in the table used for the simplified method (for calculating fuel used in heavy vehicles with auxiliary equipment), you can use other methods that are fair and reasonable to apportion fuel between on and off public roads.

Examples of other methods to calculate fuel used in auxiliary equipment include:

• actual records of fuel purchased and used if the auxiliary equipment of your heavy vehicle is fuelled by a separate tank
• actual fuel consumption data from the auxiliary equipment if it uses a power take-off connected to the module, such as engine diagnostic downloads
• running trials to compare the:
  • vehicle’s fuel consumption when the vehicle is idling with and without the power take-off engaged
  • fuel consumption of the vehicle with and without the auxiliary equipment operating.

If you’re using average fuel consumption rates that are to apply across your vehicle fleet, you must:

• have undertaken the necessary testing. The testing must take into account the age, model, GVM, driver influence, conditions (terrain and climatic conditions) and the type of activity.
• retain documentary evidence to support the fuel consumption rate being reasonable and applicable to all the vehicles in the fleet.

You can’t use an average fuel consumption rate without supporting documentation relevant to your vehicle and activity.