http://www.vcacarfueldata.org.uk/information/fuel-consumption-testing-scheme.asp

Urban cycle

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. Maximum speed is 31 mph (50 km/h), 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.

Extra-urban cycle

This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75 mph (120 km/h), 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.

http://www.vcacarfue...ting-scheme.asp

Urban cycle

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. Maximum speed is 31 mph (50 km/h), 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.

Extra-urban cycle

This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75 mph (120 km/h), 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.

i think this is the general problem people dont undwerstand how its done and take the figures as being gospel but dont understand that the test doesnt represent real world driving it doesnt take into account traffic consatntly slowing down for the 70 yr old biddy thats struggling to see the steering wheel never mind the road nor does it take into account traffic lights roundabouts speed bumps or the person in front who keeps breaking every 20 seconds etc etc etc we dont drive on flat test tracks at 20-30 degrees so as i keep saying when people complain that the mpg isnt what they say that mpg is achievable under optimum conditions