ECONOMY EXPLAINED

Between the various figures produced on the old-style NEDC, transitional NEDC Correlated and new-style WLTP laboratory emissions and fuel economy tests, it has become tricky to compare manufacturers’ claimed efficiency on the latest new cars. When you see a fuel economy and CO2 figure reference elsewhere, it’s often without explanation. So, to provide as fair and clear a basis for comparison as possible, you’ll only ever read WLTP combined fuel economy and CO2 figures in Autocar’s first drive reviews, features and comparison tests – and on these data pages. Those are the aggregated results of four lab tests carried out across as many different cruising speed ranges – although they’re sometimes expressed as a range rather than as one specific figure to show the different results recorded by the heaviest and lightest available examples of the car in question (depending on optional equipment). In road tests, you’ll also see our own independently produced real-world fuel economy test results for comparison with the lab test claims. We produce an average, track and touring figure for each car we test, as often as possible on a brim-to-brim test basis. While ‘average’ represents the overall economy returned by a new car over a full road test and ‘track’ is relevant only to intensive performance testing (the length and conditions of which can vary slightly), ‘touring’ gives the best guide of the kind of economy you might see from a car at a steady 70mph motorway cruise. We do real-world efficiency and range testing on electric cars, too, expressing the former in terms of miles per kilowatt hour, as manufacturers do increasingly widely by convention.