Independent testing by UK consumer champions Which? has found that fuel consumption tests are woefully unsuited to modern driving conditions. Which? put 200 cars through their paces using an updated test they say more accurately simulates real-world driving conditions than the tests currently carried out by the auto industry.
About a quarter of the cars tested by Which? are on the Australian market. Of those, non-electric cars had their kilometres-per-litre specs oversold by 14.3% on average.
The cars showing the greatest discrepancy in fuel efficiency between the two testing regimes were hybrids. In the full petrol and diesel cars, four of the bottom five contenders were automatics. The 3.0L diesel Jeep Grand Cherokee takes home the wooden spoon, with a 54.7% difference between what the manufacturer claimed the car could get, and what the Which? test was able to achieve.
The car that came closest to its claimed fuel efficiency? The 2.2L manual diesel Honda CRV, with Which? testers getting within 0.1L/100km of the car's stated fuel efficiency. Check out our comparison tables for the full list.