There are six forces that are directly responsible for the fuel consumption of a vehicle. Understanding how these forces work can help you limit their impact.

The figure above illustrates that the motive force (MF), which directly relates to the amount of fuel you put in your vehicle, must counteract the sum of the rolling force (RF), the aerodynamic force (AF), the acceleration force (AF), the braking force (BF) and the gravity force (GF). To lower your fuel consumption, you should reduce the extent of these forces or improve the efficiency of your engine. 

Not all forces affect fuel consumption to the same extent. The chart below illustrates the distribution of the three forces which primarily influence fuel consumption in the city and on the highway.

This chart clearly shows that in the city, the acceleration force dominates all other forces. Because of the many starts and stops that occur when driving in the city, this force is responsible for about 60% of fuel consumption. The rolling force and the aerodynamic force rank second and third in importance.