Since it is impossible to consistently duplicate on-road testing with so many variables, a controlled laboratory testing method is followed instead. This ensures that all vehicles are evaluated under identical conditions and that the results are consistent and repeatable across all manufacturers.
Estimated fuel-consumption ratings are derived from both a city and a highway test, and the values generated through this procedure allow fair and reliable comparisons of different vehicles.
The city test simulates a 12 kilometre (km) trip that includes 18 stops, while the highway test simulates a 16 km trip that does not include any stops.
The ratings reflect the results of the specific simulated tests. While the ratings are achievable under ideal conditions and when applying fuel-efficient driving techniques, the following factors can significantly affect the fuel consumption of a vehicle:
• driving style and behaviour;
• vehicle acceleration;
• braking and driving speed;
• age and condition of the vehicle;
temperature and weather
• traffic and road conditions;
• drive systems and powered accessories.
In addition, small variations in manufacturing can cause fuel consumption differences in the same make and model, and some vehicles don't attain optimal fuel consumption until they are “run in” for about 6,000 to 10,000 km.
The estimated ratings are a useful tool for comparing vehicles before you buy, but they do not accurately predict the fuel consumption you will get. Natural Resource Canada's Fuel Consumption Guide, along with additional information and tips can be found online by visiting www.vehicles.gc.ca