How is vehicle speed related to fuel consumption?

Driving speed has a significant impact on fuel consumption because both excessive speed and extremely low speeds can lead to inefficiencies in how a vehicle operates. At higher speeds, aerodynamic drag increases, which demands more power from the engine and therefore leads to higher fuel consumption. Conversely, driving too slowly can also be inefficient because it may require the engine to operate in a less optimal part of its power band, sometimes resulting in increased fuel consumption due to the engine needing to work harder than necessary to maintain the vehicle's momentum.

Finding an optimal speed is crucial for energy efficiency, typically around moderate speeds for most vehicles. This middle ground helps improve fuel economy, as the engine runs most efficiently within certain RPM ranges that are neither too high nor too low. Thus, maintaining a speed that is too fast or too slow can negatively affect fuel efficiency, confirming that both extremes ultimately consume more fuel than an optimal driving speed.