New cars are using vastly more fuel on the road than in laboratory tests, raising further questions about the veracity of car manufacturers’ claims in the wake of the Volkswagen emissions scandal.

The Australian Automobile Association-commissioned research found fuel use was on average 25% higher than claimed on the government-mandated fuel consumption label displayed on all new cars.

In some cases, they were 60% above the fuel use claimed on the label.

On-road noxious gas emissions from five diesel cars were found to be over the legal limit, in one case by up to eight times.

Two petrol cars were significantly above the limits for carbon monoxide emissions.

The research, conducted by technical consulting firm Abmarc, examined 17 new and commonly available cars in the past 10 months.

The AAA did not name and shame individual manufacturers, but said the cars were selected across brands, vehicle types and fuel types.

The 2015 Volkswagen scandal raised serious concerns about the truth of car manufacturers’ emissions claims. Volkswagen was caught installing software in cars that allowed it to game emissions tests in the United States.

That scandal was uncovered after environmental groups detected discrepancies between real-world emissions and those recorded in tests.

The federal government is currently considering tightening emissions and CO2 standards, effectively moving from the “Euro 5” to “Euro 6” standard.

That would bring Australia in line with international standards following years of lagging behind the European Union and the US.

The AAA is opposed to the government’s standards proposal, saying it will cost motorists without delivering any benefit to the environment.

It last week described the plan as an “uncoordinated process” that had no robust cost-benefit analysis.

The AAA chief executive, Michael Bradley, said the results of its latest testing showed the assumptions underpinning the government’s proposal were flawed.

“These results are bad news for Australian consumers looking for good information on which to base their car-buying decisions,” Bradley said.

“They also place a huge question mark over the fuel and cost-savings the government is offering Australians under its proposals to introduce tougher vehicle emissions restrictions.

“Our test results are a warning to Australians to take the government’s promises of fuel and cost-savings with a grain of salt, and expect those savings to be significantly less than what’s promised.”

A spokesman for the urban infrastructure minister, Paul Fletcher, said it was well known that pollutants emitted in laboratory conditions would generally be lower than on-road driving tests.



He said the way vehicles were tested for emissions was “quite separate” from the current question of whether car emissions should be changed or tightened.

“No decisions have yet been taken – the matter will be considered by cabinet later this year,” the spokesman said.

The cars tested had all driven at least 2,000km but no more than 85,000km, and were 2014 models or newer.

The cars were tested twice, from a cold start and a warm start, and were driven along the same route in Melbourne, which contained urban, extra-urban and freeway driving.

Bradley said the AAA supported reducing emissions and strengthening standards, but said policy must “deliver for the environment at the least cost to motorists and the economy”.

“The AAA and Australia’s motoring clubs again call on the government to update its modelling, undertake further public consultation and introduce real-world driving testing for new vehicles in Australia,” he said.

The federal government allows the use of test results from international laboratories for assessment against Australian standards. The government also audits test results.

The ministerial forum on vehicle emissions is considering how to reduce emissions from Australia’s vehicle fleet. It has released three papers for consultation, including a draft regulation impact statement on new fuel efficiency and noxious emissions standards.

Those impact statements included a cost-benefit analysis of the changes, which considered recent studies on the discrepancies between laboratory-tested and on-road emissions.

To address the discrepancy, the statements recommended adopting the latest standards, which introduce a more representative laboratory test and an on-road driving emissions test.