A popular diesel-powered 4x4 dual-cab ute that used 6% more fuel than its mandated laboratory fuel consumption figure and a petrol-hybrid SUV that used 7% more were among the results from the Australian Automobile Association’s (AAA) latest fuel consumption and emissions testing.

The AAA said the data from its fourth round of testing confirmed that consumers should not assume laboratory tests on a car’s fuel consumption and environmental impacts provided an accurate indicator of vehicle performance in the real world.

The latest tests did not find the large variations revealed in previous rounds, with the MY24 Isuzu Ute D-Max 4x4 (+6%) and the MY24 Toyota Corolla Cross Hybrid (+7%) showing the greatest difference between their lab result and their real-world results.

In the case of the Corolla Cross, that meant a real-world result of 4.5L/100km versus its mandated lab result of 4.2L/100km, while the D-Max’s real-world result was 8.5L/100km versus its lab result of 8.0L/100km.

Both vehicles also returned higher CO2 emissions than their mandated lab results.

One vehicle, the MY23 Audi Q5 exactly matched its mandated laboratory fuel consumption, while several others including the MY23 Kia Carnival (-2%), MY23 Kia Sorento (-2%), MY23 Audi Q3 (-3%), MY23 Hyundai Tucson (-3%) and MY24 Subaru Forester (-3%) delivered better real-world consumption than their lab result.

Find out more about the Real-World Testing Program

Despite this, the AAA said the overall results of its first full year of the Real-World Testing Program showed that some cars tested consumed as much as 31% more fuel in real-world conditions than their mandatory laboratory tests.

In addition, 21 of the 58 cars tested produced on-road emissions that exceeded current or upcoming Australian regulatory lab limits for toxic tailpipe emissions.

“We can now say with confidence that while some vehicles produce fuel consumption and emissions in line with lab tests reported by carmakers, many do not,” said AAA Managing Director Michael Bradley.

“That can have real impact on consumers and fleet buyers. If people rely on the lab tests, they could end up with a car that costs more to run or is dirtier than they expected.

“The results raise a question for regulators about whether car dealerships should be required to reveal real-world testing results to consumers at point of sale.’’

The $14 million, four-year Real-World Testing Program is run by the AAA and funded by the Commonwealth.

It was created in response to the 2015 Volkswagen emissions scandal, which showed that emissions regulations around the world incentivised carmakers to optimise their vehicles’ fuel consumption and emissions performance for the laboratory tests being used for regulatory compliance.

Mr Bradley said the world-first program had now tested enough cars, SUVs, utes and people movers to enable consumers to examine the results for multiple vehicle models within the same class, which they can use as part of their new car buying research.

“If you are buying a small car, for example, we’ve now tested eight small-car models from different manufacturers, giving consumers a chance to understand real-world fuel consumption and emissions before they buy,” he said.

“We also now have multiple vehicle results across various vehicle classes, including small, medium and large SUVs, as well as utes.”

The latest tranche of test results showed 15 cars across a range of classes consumed as much as 7% more fuel than reported in lab testing, while five consumed less fuel on the road than in the lab.

It also found that although four diesel vehicles recorded real-world fuel consumption rates close to lab test results, all four produced noxious emissions above the mandated lab-test limits.\

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The four-year RWT program will test up to 200 cars, SUVs, and utes, including electric vehicles.

Under the Real-World Testing Program, cars are tested on roads in and around the Victorian city of Geelong under strict test protocols to ensure fuel consumption and emissions results are repeatable and minimise the influence of human factors such as driving style and changing traffic flows.

For research purposes, the AAA undertook 23 tests on the program’s reference vehicle (a Toyota RAV4), with fuel consumption across these tests having less than 2.5% variability.

The AAA is the nation’s peak motoring body, representing Australia’s state-based motoring clubs and their 9.3 million members.