New emissions rules come into force – the WLTP

Motorists are set to benefit from more realistic emissions and fuel economy data after two new EU car tests come into force today, replacing a single test that hasn’t been updated for some 20 years.

The new tests, which measure everything from fuel consumption and carbon dioxide (CO2), to nitrogen oxides (NOX), particulates by mass and number (PM/PN) and carbon monoxide (CO), are part of European regulations designed to improve air quality and tackle climate change. As well as a tough new laboratory test, all newly launched car models will have to undergo robust official on-road testing before they go on sale – an element that no other vehicle testing regime in the world requires.

Over the past 20 years, vehicles have advanced at a rapid rate, with high tech safety and comfort features. However, the way they are tested has not kept pace, resulting in a gap between performance in the lab and on-road where conditions such as speed, congestion, road surface and driving style can vary dramatically from journey to journey and driver to driver.

EU regulators and national governments have been working, with the support of industry, to address this by making testing more relevant to modern vehicles and consumer needs.

From 1 September, every new car model destined for UK showrooms will need to undergo a new test called the Worldwide Harmonised Light Vehicle Test Procedure (WLTP), which measures all regulated emissions, as well as CO2 and fuel economy. Like the previous test, it is conducted in controlled laboratory conditions for consistency across every test and every new vehicle in every country. However, it is faster, longer and more dynamic, with a greater range of vehicle and engine speeds, engine load, gear changes and temperatures. It will also take into account modern vehicle technology. And, because it is based on some half a million miles of real driving data, it will be far closer to the conditions most people experience on the road today.

Secondly, new models being developed for sale in the UK will also need to prove their air quality credentials by passing a brand new Real Driving Emissions (RDE) test using special portable emissions measurement (PEMS) equipment. This equipment analyses the trace tailpipe emissions of pollutants, including NOX and particulates, while the car is driven in a wide range of both every-day and extreme conditions. This will ensure vehicles meet the tough Euro 6 emissions standard on the road as well as in the lab.

The WLTP and RDE tests replace the previous and long-outdated laboratory test known as the New European Driving Cycle (NEDC), which was designed back in the 1980s and last updated in 1997. Revolutionary in its day, NEDC was intended to provide consistent benchmarking information for buyers across Europe as well as determining whether cars meet minimum air quality standards and providing the basis for the UK’s CO2-based Vehicle Excise Duty system.

How the new Worldwide Harmonised Light Vehicle Test Procedure compares

Newly designed cars will start to be tested under the new regime over the coming months after the final piece of legislation specifying the requirements that allow testing authorities and manufacturers to prepare was published in July this year. This means consumers could start to see these brand new models arrive in showrooms from as early as next year.

By 1 September 2018, all new cars on sale will have undergone WLTP testing and by 1 September 2019, all will have undergone the full RDE testing for both NOx and PN.

The Founder of driveEV. A driving and new technology fan enjoying learning all about the future of motoring. I drive a BMW i3.