Ever wondered how fuel economy is tested?

Fuel economy is always important when purchasing a new car. Manufacturers are required to test fuel economy in line with a mandated procedure (detailed under the Australian Design Rule (ADR)).

The full testing procedure for light vehicles is conducted over a continuous 20 minutes and is split into urban and extra-urban cycle. The urban cycle testing makes up about 67% of the test, while the extra-urban cycle makes up the remaining 33%.

The urban cycle consists of a lower average speed – designed to replicate city driving with a constant element of stop/start driving at an average speed of 19km/h with considerable idle periods.

While the extra-urban cycle consists of a higher average speed of 63km/h with a peak speed of 120km/h.

Here are some interesting facts about the tests run

-       All of the vehicles that are tested need to have 0 kilometres on the odometer.

-       A number of readers are taken to determine fuel consumption. The density of the fuel used, the emission of hydrocarbons, carbon monoxide and carbon dioxide are added together in a calculation to determine the fuel consumption.

-       The tyre pressure, engine oil viscosity and all other consumables need to be at the recommended manufacturer levels.

-       The lights and signalling devices are switched off or are in the normal operating state.

-       Testing is conducted between 20 and 30 degrees Celsius ambient temperature. 

Next time you buy a car and wonder if the fuel consumption is actually the truth, now you know how they get to that number! Just remember that your driving won’t be the same as test conditions, braking late and accelerating hard will increase consumption.