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November 2015

The Volkswagen Group may be taking all the heat at the moment, but the vehicle-emissions scandal is something all carmakers should pay serious attention to.

What it brings into question is the legitimacy of manufacturer-quoted fuel-economy figures. There are several standards – NEDC in Europe, EPA Federal Test in the USA and JC08 in Japan – and, while they do represent a baseline for equal comparison between vehicles, they don’t mimic realistic driving conditions. To the great frustration of motorists all over the world, we rarely get close to figures quoted by manufac- turers. How could we? Those claims are set by vehicles that are run in a laboratory at sea-level conditions across extended steady-state speed sections with conservative acceleration/deceleration, without a wind blowing nor electrical ancillaries (like air-con) switched on. It’s simply not the same as real-world driving.

So our vehicles use more fuel than is claimed …
and, of course, the more fuel a vehicle uses, the greater volume of harmful emissions it produces. With this in mind, the respected environmental organisation Euro- pean Federation for Transport and Environment claims that European vehicles emit 40% more mono-nitrogen oxides (NOx) than shown by the lab-run tests.

Cheating on emissions tests is one thing, but of greater importance is quoting realistic fuel consump- tion stats for each vehicle. Not only will prospective purchasers know what vehicles will cost them to run, but we will all have a more accurate idea of just how much CO2 and other harmful gases and particulates vehicles with internal-combustion engines produce.

Representative fuel economy is the reason CAR magazine does its own fuel run for every vehicle we test. The route is 100 km long and contains a mix of urban and highway driving. For vehicles we haven’t tested, we quote the CAR fuel index figure, which is the manufacturer’s claimed figure plus an extra 20%.

We love cars and we want to continue driving them. However, it’s a pleasure that is under threat when car- makers fail to comply with emissions regulations. I hope the scandal serves as a wake-up call to the industry.

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CAR magazine