VW scandal highlights unrealistic lab tests

Volkswagen’s diesel emissions scandal continues to damage the German brand, with its share price tumbling, the threat of legal action from VW owners and sales of VW diesels on hold in some European countries.

VW has responded by shuffling its senior management and replacing its CEO, but VW diesel owners are still largely in the dark about what will happen to their cars.

VW Australia still waiting

Australian VW dealers are still waiting for information from Germany about the status of Australian VWs following the company’s admission that it used “defeat” devices to pass emissions tests in the US.

The revelations of VW’s rorting of the emissions laboratory tests has raised questions about how accurately lab tests for emissions and fuel consumption reflect results in real world motoring conditions.

Lab tests vs. real world driving

Standard laboratory tests might place all cars on a “level playing field” but they don’t reflect real driving conditions, so drivers are unlikely to get anywhere near the official fuel consumption figures, while emissions may well be higher than published as well.

According to many reports, carmakers have been using a number of tricks to improve fuel consumption in lab tests. These include:

  • Taping up door cracks and grilles to reduce drag;
  • Switching off air conditioning and other energy using accessories;
  • Using higher gears to make engines run more efficiently than normal;
  • Using special lubricants to reduce friction for improved efficiency;
  • Over-inflating the tyres to reduce rolling resistance as well as using special tyres with a low rolling resistance;
  • Altering wheel alignments to further reduce rolling resistance; and
  • Disconnecting the alternator to prevent the battery from charging and reduce energy use.

Such “tricks of the trade” may not be actually illegal but it’s definitely “gaming” the system.

Transport & Environment, a European group campaigning for more sustainable transport, claim “the gap between official test results for fuel efficiency and CO2 emissions and real world performance on the road is growing rapidly.”

The group says the test cycle doesn’t reproduce the way cars are driven and that the test procedures are “obsolete and lax” and “full of loopholes”.


The revelations have caused some in Australia to consider legislation to fine carmakers up to $50 million for “wildly inaccurate” fuel consumption figures.

Regardless of whether any legislation ever sees the light of day, there’s a real need to make testing for emissions and fuel consumption reflect real world driving conditions.

The American EPA has recently announced that it will be increasing its enforcement regime for vehicle emissions and doing spot checks on vehicles using “driving cycles and conditions that may reasonably be expected to be encountered in normal operation and use”.

Given the widespread “gaming” of laboratory testing that could be quite an eye opener and more than a little concerning for a number of carmakers.

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