New mpg tests on way

Car industry experts are revamping the way fuel economy is calculated to make it closer to real-world driving.

Auto Express has led calls for the current system – which produces Urban, Extra-urban and Combined figures via irrelevant lab testing – to be scrapped. In its place should be a classification which more accurately reflects what motorists might expect to achieve day-to-day.

And it looks as though that’s going to happen. Discussions on drawing up the new system – to be called the Worldwide Light-duty vehicle Test Cycle (WLTC) – are now underway.

The plan is a joint venture between the European Commission and the United Nations, and would create a global standard for setting fuel economy and exhaust emissions figures. It would also define how diesel particulates are measured and procedures to quantify energy consumption of hybrids and EVs.

Documents seen by Auto Express suggest the WLTC would apply across the UK and Europe, as well as in China, India, Japan, South Korea and the US.

One idea known to be on the table is publication of two mpg figures for every new car, giving a best and worst-case scenario. The first would come from testing an empty vehicle with all ancillary systems – such as the air-con, audio and headlights – switched off. The second would be from a car with all this kit turned on and a full complement of passengers.

The news has been welcomed by the UK’s car industry umbrella organisation, the Society of Motor Manufacturers and Traders. It said the change would remove the current focus on developing new technology that helped cars perform well in mpg and CO2 tests, but not on the road.

Just don’t expect any change quickly. The WLTC review isn’t due for completion until 2014, and new rules won’t come into effect for at least three years after that.