A purportedly eco-friendly hybrid electric car emits four times more greenhouse gas than manufacturers claim, according to a report backed by Australia's motoring heavyweights that opens up a new front in the nation's energy policy tussle.
The report by the Australian Automobile Association, members of which include the NRMA and RACV and RACQ, says real-world testing reveals some new cars are using up to 59 per cent more fuel than advertised. Almost six in 10 exceeded the regulated limit for one or more pollutant in cold-start tests.
The AAA says consumers are being "increasingly ripped off", forking out for vehicle technology that cuts emissions in the laboratory, but not on the road.
It says the findings cast doubt on whether more stringent vehicle emissions laws - a move being considered by the Turnbull government - would reduce pollution and lower fuel use.
But environment groups accused the association of spreading "misinformation" and seeking to derail attempts to make Australian cars less polluting.
The AAA report, conducted following the Volkswagen emissions testing scandal, tested 30 popular Australian passenger and light commercial vehicles on Melbourne roads. It did not name makes or models.
Emissions and fuel use were tested under real driving conditions, with Australian fuel types, and urban, rural and freeway settings.
The report found that, on average, real-world fuel consumption was 23 per cent higher than laboratory results, including one diesel vehicle that used 59 per cent more fuel than lab tests indicated.
One fully charged plug-in hybrid electric car consumed 166 per cent more fuel than official figures suggest - or 337 per cent more when tested from a low charge. It also emitted four times more carbon dioxide than advertised.
Of 12 diesel vehicles tested, 11 exceeded the laboratory limit for nitrogen oxides emissions. Overall, 18 vehicles, or almost 60 per cent, failed to achieve the regulated emissions limit for one or more pollutant in cold-start tests.
The report concluded that vehicles with the highest emission standards had the largest discrepancy between lab and on-road fuel use results, and urged regulators to be "cautious" when implementing new vehicle emissions laws.
AAA chief executive Michael Bradley said Australia's motoring clubs want appropriate pollution reduction but "real world testing is clearly required if either consumers or the environment are to benefit".
The government has proposed reducing new car emissions to 105 grams of CO??? per kilometre by 2025 - a change Mr Bradley has previously said was "extreme" and would make vehicles more expensive.
ClimateWorks Australia project manager Claire Painter said the government must include light-vehicle CO??? emissions in its upcoming climate policy review if Australia is to meet its obligations under the Paris climate deal. The proposed new standard could save the average motorist $519 a year in fuel costs, she said.
Ms Painter accused the AAA of seeking to delay the introduction of new standards while the emissions testing regime was improved - adding this was unnecessary because while discrepancies existed between lab and on-road test methods, "the absolute emissions saved is roughly the same for both tests".
Australian Conservation Foundation chief executive Kelly O'Shanassy urged the government "not to be put off by misinformation and to adopt strong pollution standards".
A spokesman for consumer group Choice, Tom Godfrey, said the test results showed consumers could not trust the fuel efficiency claims made by car manufacturers and "real world testing is clearly needed to ensure consumers are getting what they're paying for".
Mr Godfrey rejected suggestions this should mean the delay of more stringent emissions standards, saying "the government can walk and chew gum".
A spokeswoman for Urban Infrastructure Minister Paul Fletcher said a ministerial forum on vehicle emissions could assess the merits of real world testing.
