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Fuel consumption test

The internationally-agreed test is in two parts: urban cycle and extra-urban cycle.

The cars tested have to be run in and must have been driven for at least 1,800 miles (3,000 kilometres) before testing.

Urban cycle test explained

The urban test cycle aims to simulate driving conditions in and around town. It is carried out on a rolling road in a laboratory with an ambient temperature of 20 degrees Celsius (°C) to 30°C. The test begins immediately from a cold start, that is, where the engine has not run for several hours. The cycle consists of a series of:

• accelerations
• steady speeds
• decelerations
• idling

The maximum speed in the test is 31 miles per hour (mph) or 50 kilometres per hour (km/h), average speed 12 mph (19 km/h) and the distance covered is 2.5 miles (4 kilometres).

Extra-urban cycle test explained

The extra-urban cycle aims to simulate town driving on sections of faster road such as dual carriageways and national speed limit areas. This cycle is conducted immediately following the urban cycle and consists of:

• roughly half the test at steady-speed driving
• some accelerations
• some decelerations
• some idling

The maximum speed in the test is 75 mph (120 km/h), average speed is 39 mph (63 km/h) and the distance covered is 4.3 miles (7 kilometres).

Combined fuel consumption figure

The combined fuel consumption figure is the urban and the extra-urban cycle together. It is an average of the two tests, weighted by the distances covered in each one.

Bi-fuelled vehicles

Vehicles that are designed to run on liquefied petroleum gas (LPG) or compressed natural gas (CNG) and petrol need to be tested on both fuels. Because of this, two sets of figures will be shown for the vehicle. One set is for the vehicle running on petrol and another for the vehicle running on gas.