Fuel economy gap remains 5%

Testing has found that the gap between claimed fuel economy and actual fuel economy is close to five per cent.

According to What Car?’s True MPG tests, the five per cent gap is marked improvement from the 23.5% average shortfall for cars tested before the
Worldwide Harmonised Test Vehicle Procedure (WLTP) was introduced by the European Union in September 2017 , but highlights the fact that consumers should remain wary of taking official figures for granted.

What Car? compared the real-world economy figures achieved under its True MPG real-world test against official recorded figures recorded using the new, tougher-than-ever WLTP tests.

In a 15-vehicle sample that ranged from small hatchbacks to SUVs, petrols to diesels and automatic to manual gearboxes, What Car? found the manufacturer quoted economy figures were, on average, 4.9%, or 2.6mpg, higher than its testers achieved.

What Car? tested a separate 15-car True MPG sample against results gathered on the older and less accurate New European Driving Cycle (NEDC) tests, but found none exceeded official figures under real-world conditions.

The WLTP was introduced to assess new vehicle emissions and fuel economy more accurately. The WLTP protocol replaced the NEDC type approval process.

Steve Huntingford, editor of What Car?, said, ‘For years fuel economy figures recorded under the official test regime have been almost unachievable under real-world driving conditions, so it’s great to see that the new, tougher tests have closed the gap so significantly.

‘However, while it’s heartening to see some cars actually beating their official figures, we mustn’t lose sight of the fact the gap between official figures and our real-world tests remains, on average, at almost five per cent.’