Vehicles' fuel efficiency and battery range falling short

Eight out of 10 internal combustion powered cars tested in an extensive real-world testing program conducted by Australia’s peak motoring organisation have been found to use more fuel than advertised, while every electric vehicle tested so far has failed to achieve its reported laboratory driving range.

The details are included in the latest batch of program results released by the Australian Automobile Association (AAA), which has been conducting its Real-World Testing Program on new electric, hybrid, petrol, and diesel cars since October 2023.

The Commonwealth-funded program has now tested 141 petrol, diesel and hybrid vehicles, with 76% found to use more fuel in real-world conditions than advertised.

Electric vehicles (EVs) are also failing to match their reported laboratory driving range or travel distance on a single battery charge, with the AAA program having now tested 11 EVs, all of which failed to achieve their stated range, with shortfalls ranging from -3% to -31%.

The Real-World Testing Program compares vehicles’ fuel consumption and emissions, or in the case of battery electric vehicle their driving range, in Australian driving conditions with the laboratory test results reported by car manufacturers.

The testing program is conducted in and around Geelong, Victoria, and complies with strict guidelines based on European Union legislation and developed in consultation with Australian regulators and industry. The organisation claims this ensures results are repeatable and minimises the influence of human factors such as driving style and changing traffic flows.

In the latest round of its Real-World Testing Program the AAA found that eight out of the 10 internal combustion engine vehicles tested used more fuel on-road than advertised, with the worst result being the GWM Tank 300 which used 25% more fuel in the real world than in its laboratory test (11.9L/100km v 9.5L/100km).

The laboratory test is the fuel consumption and emissions figures car makers are required to display on the windscreens of new vehicles sold in Australia, which many consumers rely on as a guide to a vehicle’s fuel efficiency.

However, the growing body of data gathered via the AAA test program shows these laboratory-generated figures cannot be relied upon as a guide to what a vehicle will achieve in real-word driving conditions.

AAA Managing Director Michael Bradley said the program had been created in response to Volkswagen’s ‘dieselgate’ scandal, which erupted in 2015 and revealed the German auto giant had misled millions of consumers across the globe by cheating laboratory tests.

A Ford Mustang GT used for the Real-World Test Program.

The Ford Mustang sports car and Mercedes-Benz GLE 450d Large SUV were the only vehicles in the latest round of test results to deliver a better fuel consumption result than their lab fuel result.

In the case of the Mustang, both the four-cylinder powered EcoBoost model (-6%) and the 5.0-litre V8-powered Mustang GT (-22%) bettered their lab fuel result during real world testing. In the case of the V8 Mustang that meant real world fuel consumption of 10.7L/100km, versus its advertised lab result of 13.6L/100km.

The Mercedes-Benz GLE 450d, meanwhile, used 11% less fuel than its advertised lab result, with the high-performance luxury SUV’s mild-hybrid assisted 3.0-litre inline six-cylinder turbodiesel using 6.6L/100km versus its advertised figure of 7.4L/100km.

While a smaller sample size of EVs have been tested by the program to date, the latest test results of two battery electric vehicles show one delivering a driving range 10% below that reported on the windscreen label (BMW iX1) and the other a driving range 25% below
the label (BYD Seal).

In the case of the BMW iX1 small SUV this meant a real-world testing range of 360km versus its advertised laboratory range of 400km, while the BYD Seal medium car achieved a real-world range of 488km versus an advertised laboratory range of 650km.

“Giving consumers independent information on real-world battery range means they now know which cars perform as advertised, and they can worry less about running out of charge and make the switch with confidence,” Mr Bradley said.

The latest results came after the Government released the first batch of New Vehicle Efficiency Standard (NVES) compliance figures for each car importer, which showed carmakers
will come under increasing pressure to produce lower emissions.

“The AAA supports the introduction of increasingly stringent vehicle emissions regulation, but we also want to make sure our car fleet is getting cleaner in the real-world, not just in the lab,” Mr Bradley said.

“By independently measuring fuel use and emissions performance in real-world conditions, this Program provides transparency about NVES-related emissions reductions, and the degree to which they are being realised on Australian roads.”

All program results are available at realworld.org.au