Real World Vehicle Fuel Consumption (Ongoing)

Overseas studies have shown significant differences between manufacturers' fuel consumption claims for their vehicles and the vehicles’ real world fuel performance. The AA Research Foundation is funding research on how we could develop a better understanding of real-world fuel efficiency in the New Zealand fleet.

Stage One

The gap between official vehicle fuel consumption figures and the actual fuel consumption performance that drivers experience has been steadily worsening, according to the International Council on Clean Transportation.

On average the fuel efficiency of the latest vehicles is 42% worse than claimed by their manufacturers.  This has implications for both consumers and government policy.

For government, it has implications for CO2 abatement policies in the light of the Paris Accord. For vehicle owners, it could mean paying in the region of $650 more per year for fuel than the estimates provided by (provides information on manufacturers’ fuel consumption statistics).

Stage One of this AA Research Foundation programme examined currently available fuel consumption data and looked into options for collecting real-world fuel consumption data. The study looked at a range of data from both New Zealand and overseas. The research concluded that in principle, there are models available from overseas that may be able to be adapted to the New Zealand context – but considerable further work would be required.

Why is the AA Interested?

Light vehicle emissions comprise an eighth of New Zealand's total greenhouse gas emissions. While electric vehicles offer one solution, they will take decades to become a significant proportion of the New Zealand fleet. With current technology they are also not suited to every vehicle owners’ needs. The AA is therefore interested in measures to reduce the emissions of the conventional internal combustion fleet. This must start with good data on the actual performance of vehicles on New Zealand roads.

Stage One - Results

The study found that not only has the divergence between real-world fuel economy and manufacturers’ claimed fuel economy been growing, but that it is quite possible that the fuel economy of some of the latest model vehicles is worse than their predecessors from 10 years ago.

It concludes that there is a need for better consumer information about real-world fuel consumption sourced from ordinary New Zealanders. The research suggests which features of international research are best to replicate in New Zealand and which are best to avoid.

This AA Research Foundation study was carried out by New Zealand air quality consultancy Emission Impossible Ltd, following up their work for the NZ Transport Agency into the real-world tailpipe emissions of 26 commonly used vehicles in New Zealand.

Report - Results of Stage 1 of the Real-World Fuel Consumption Project


  • Dr Gerda Kuschel – Emission Impossible Ltd
  • Jayne Metcalfe – Emission Impossible Ltd

Project Managers

  • Simon Douglas - AA Research Foundation
  • Peter King - AA Research Foundation

 Page last updated: November 2019

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