When you want to know how much carbon dioxide a light vehicle emits, it must be measured in grams per kilometre. You do this using an approved test cycle. The amount of carbon dioxide emitted is determined by regulations or rules made under the Land Transport Act. You find out how much carbon dioxide a vehicle emits by following the regulations or rules. If a vehicle's emissions were measured using a different test cycle, you must follow the regulations to determine the emissions. This might involve estimating what the emissions would have been if the approved test cycle was used. The regulations or rules will help you work out the carbon dioxide emissions of a vehicle, even if it was not tested using the approved cycle. You can find more information about the rules in the Land Transport (Clean Vehicles) Amendment Act 2022. The rules are there to help you understand how carbon dioxide emissions are measured and determined.