All new car registrations will be subject to a more rigorous fuel economy test from 1st September 2018, as a new EU backed procedure continues its roll out. The old NEDC test, which is used for establishing official Fuel Consumption and CO2 emissions, has been phasing out since mid-2017 and replaced by the Worldwide Harmonised Light Vehicle Test Procedure (WLTP).

Manufacturers have been able to request WLTP approvals for new car types – vehicle models introduced onto the market for the first time – since the end of July 2017. In September 2017, this became mandatory for all new car types, and from September 2018 the new testing regime will apply to all new car registrations, including older models. However, EU measures for end-of-series cars allow for a limited number of unsold vehicles in stock approved under the NEDC test to be sold until September 2019.

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Why the change in car fuel economy testing?

The new test aims to provide more accurate, real-world results, as well as model specific values at the point of sale. Manufacturers and retailers could see this hit sales of certain models, as Cap HPI found an average 10% rise in emissions, reported AM Online. Their study found diesel vehicles increased by 12.6%, petrol by 7.3%, petrol/plug-in hybrid by 27.3% and petrol hybrid 7.8% under the new WLTP test.

Fuel economy is a key selling point for consumers. Manufacturers are constantly innovating to improve their engine technology to reduce consumption and CO2 emissions. Unfortunately, this strive for better vehicle statistics also led to the emissions scandal, which rocked several manufacturers in recent years. Using the new WLTP figures, consumers will be able to make more informed purchasing decisions, and gain a better idea of how many MPGs they can get in their new car.

The European Automobile Manufacturers Association (ACEA) has said that, in the view of the auto industry, all dealerships should have WLTP values only to avoid confusion among consumers from 1st January 2019. This will avoid the comparison of more favourable NEDC figures with WLTP.

How does the new WLTP fuel economy test work?

The WLTP is a laboratory test that measures fuel consumption, CO2 emissions, pollutant emissions and energy consumption values of alternative powertrains. Conducted on a rolling road, the test takes 30 minutes and 14.4 miles, compared with the NEDC’s 20 minutes and 6.8 miles. It also covers a wide range of driving behaviours and speeds, utilising stops, acceleration and braking phases to create a more accurate representation of real-world conditions.

Combined with the Real Driving Emissions (RDE) test, which came into force on 1st September 2017, consumers will get a much more accurate representation of how their car will perform. The two tests are designed to complement each other, with RDE involving the car being driven on public roads and over a wide range of conditions (further RDE information).

While the changing fuel economy testing regime may seem like a headache for manufacturers and retailers, it should improve consumer confidence and create a more level playing field between vehicle makes and models.