Is your car under-delivering on fuel economy?


You may think you're buying a fuel-efficient vehicle, but tests for Australian conditions could prove otherwise.

  • Finance
  • Read Time: 4 mins

Did you know that the advertised fuel economy for a new vehicle is determined in an overseas laboratory, and does not necessarily reflect its performance on Australian roads?

An Australian Automobile Association (AAA) study of 30 popular cars found that, on average, cars consumed 23% more fuel in real-world conditions than in lab tests. Additionally, the real-world results achieved by 11 of the 12 diesel vehicles tested exceeded regulatory laboratory noxious emissions limits.

The tests, conducted in 2017, revealed cars which supposedly consumed about 8.5 litres per 100 kilometres actually consumed about 10.8 litres on average.

If one of those vehicles carrying petrol bought at $2 a litre was driven from Sydney to Canberra, the cost of that trip would be $62 rather than $49.

Over a year, this difference could add hundreds of dollars to the average Australian petrol bill.

When you buy a new car, it's almost impossible to know whether it is actually fuel efficient or it has just been engineered to do well in a lab test. 

Fuel consumption stickers currently note performance will differ in real-world conditions, but that can vary greatly from car to car.

Australian testing


As a follow-up to the 2017 study, the AAA has begun testing 200 cars in real driving conditions over four years. The aim is to quantify how each vehicle’s fuel economy and emissions performance varies from the lab test results reported at point of sale.

AAA managing director Michael Bradley said the Real-World Testing Program, which began in August 2023, could lead to consumer savings and be good for the environment.

“This program will deliver Australians truth-in-advertising and drive down demand for cars that over-promise and under-deliver,” he said. 

“Better information will enable families and fleet buyers to buy vehicles that will meet their budget and environmental requirements.”

The federal government allocated $14 million to fund the program over four years.

Initial results will be reported in November via www.realworld.org.au and promoted by the AAA’s affiliated clubs, which have 8.9 million members across Australia.

Related reading: AAA, ABC

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