The fuel consumption testing scheme
The fuel consumption testing scheme is intended to give potential car buyers comparative information about the relative fuel consumption of different models in standard tests.
Nearly all new car models which are type approved for sale in the European Union have to undergo the standard tests to determine their fuel consumption. This guide contains the results of those tests supplied to the Department for Transport for new cars expected to be on sale after August 2013.
What are the Standard Tests?
Official fuel consumption test procedures have been in use since the 1970s. EU Directive 80/1268/EEC as amended or, for Euro 5 vehicles onwards, Regulation 692/2008 describe the tests which all new cars on sale after 1 January 2001 are required to take.
Fuel Consumption Test
The current test for conventional internal combustion engine vehicles has two parts. These are an urban and an extra-urban cycle. The test cycle is the same as that used to determine the official exhaust air quality pollutant emission classification for the model of vehicle in question.
The cars tested have to be ‘run-in’ so they must have been driven for at least 1,800 miles (3,000 kilometres) before testing.
The urban test cycle is carried out in a laboratory at an ambient temperature of 20°C to 30°C on a rolling road from a cold start where the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerations and idling. The maximum speed is 31 mph (50 km/h). The average speed 12 mph (19 km/h) and the distance covered is 2.5 miles (4 km). The cycle is shown as Part One in the diagram below.
The extra-urban cycle is a cycle that is intended to represent the use of the vehicle on roads that are external to the urban environment. The cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving with the remainder being accelerations, decelerations, and some idling. The maximum speed is 75 mph (120 km/h). The average speed is 39 mph (63 km/h) and the distance covered is 4.3 miles (7 km). The cycle is shown as Part Two in the diagram below.
Combined Fuel Consumption Figure
The combined figure presented is for the urban and the extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part.
The fuel consumption figures quoted in this guide are obtained under specific test conditions, and therefore may not necessarily be achieved under ‘real life’ driving conditions. A range of factors may influence actual fuel consumption - for example, driving style and behaviour, as well as the environment and conditions under which the vehicle is operated. Furthermore, since several different specifications (variants or versions) of a given model may be grouped together in the list, the figures used in this guide should be treated as indicative only.
A definitive figure for a given specification of vehicle will be available at the point of sale.
Vehicles which are designed to run on LPG or CNG and Petrol are required to be tested on both fuels. In view of this, two sets of figures will be shown for a given bi-fuel vehicle. One set for the vehicle running on petrol, and another for the vehicle running on gas.
How Representative of Real Life Driving are the Standard Tests?
Because of the need to maintain strict comparability of the results achieved by the standard tests, they cannot be fully representative of real-life driving conditions. Firstly, it is not practicable, nor is it viable to test each individual new car. Only one production car is tested as being representative of the model and this may produce a slightly better or worse result than another similar vehicle. Secondly, there are infinite variations in driving styles, as well as road, car and weather conditions, all of which can have a bearing on the results achieved. For these reasons the fuel consumption achieved on the road is unlikely to be the same as the official test results. The purpose of the official fuel consumption test is to provide data that will permit a comparison of the fuel consumption of different cars, rather than to provide an estimate of average, on-the-road, fuel economy.
It is recognised that, for a variety of reasons, the fuel consumption achieved by the majority of motorists is poorer than that suggested by the standard tests, and work is going on with the intention of introducing a new test cycle which will better represent the way in which most people actually use their cars.
Who Does the Testing?
The testing is carried out either by independent test organisations, or by the vehicle manufacturers or importers themselves, usually at their own test facilities.
In the UK, and before the results are officially recognised, the DfT will:
Are All Models Included in the List?
Almost all types of new passenger cars have to be tested. However, several models which do not differ significantly in certain technical characteristics important in determining fuel consumption may be grouped together into a ‘class’. Only one representative car of each class needs to be tested.
Certain types of vehicles are excluded from the fuel consumption testing scheme. These are cars manufactured in low volume, cars adapted to carry more than eight passengers (excluding the driver), three-wheelers, invalid carriages, van-derived passenger cars and cars built specially for export. These vehicles will not, therefore, be labelled in showrooms.
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