Naturally, fuel consumption can be affected by changing the position of the throttle regularly. On a long trip, where the vehicle’s speed can be kept constant, cruise control is useful in reducing fuel consumption because it helps keep the throttle at a constant opening. When there is a need for a change in throttle, this typically takes place more gradually than would be the case without cruise control engaged. On flat roads, this generally results in better fuel consumption. In hilly areas, intervention by the driver is often required to maximise fuel economy because drivers can usually make better use of the vehicle’s momentum.