by James Dreamer

Created on: June 06, 2008

How Driving Slowly Saves Gas

The easiest way to illustrate how slower driving saves gas is to compare driving your vehicle to riding a bicycle. Anyone who has ridden a bike knows which driving habits consume energy and which ones conserve it. Apply the same techniques of energy conserving bicycle riding to how you drive your vehicle and you can save a substantial amount of fuel.

Why does it take more energy to ride a bike quickly than it does to ride it slowly? The weight is constant at any speed. The friction is constant at any speed. What then, takes more energy as speed increases? Displacing the air. Air has mass and therefore requires energy to move. When your bike passes through the air you must accelerate the still air in front of you to move it out of your way. When riding a bicycle slowly the air requires little energy to move because at low speeds you only need to accelerate it a small amount. As your speed increases, so does the energy needed to accelerate the air, because you must accelerate it to a faster speed.

The same physical laws apply to your automobile. As you drive through the air at low speeds, you must accelerate the still air around you to those same low speeds. This takes a relatively small amount of force to accomplish. When you drive fast however, you must accelerate the still air to a much higher speed. This takes a greater amount of energy. Since that energy is provided by the internal combustion engine and that engine derives its power from its fuel, more fuel must be consumed to achieve higher speeds. This drag, as it is called, affects all objects moving through the air.

Obviously, the whole traffic world moving along at ten miles per hour would be impractical. We burn more fuel for the convenience of arriving at our destinations sooner. Speed limits are set not only with safety in mind, but also fuel consumption. (Remember when the US instituted the fifty-five mile per hour limit during the gas crises of the seventies?) Still, there are some driving habits you can practice to stretch your mileage.

Keep your speed at, or slightly below the average speed of traffic around you. This will consume less fuel than above average speed and not upset the other drivers with whom you are sharing the road. When there is no other traffic present you can drive as slowly as you wish and save even more gas. Be aware that other drivers may be in a hurry and not trying to conserve. They may approach you at a higher speed not expecting you to be moving so slowly. Try to conform to average speeds when other traffic approaches, especially from behind.

Accelerating reasonably from a stop will help conserve fuel also. Jack rabbit starts, as they are called, might get you up to speed faster, but require a much greater amount of fuel to do so. The amount of time they save is minute compared to the cost both in fuel and wear and tear on your vehicle.

Decelerating slowly can also boost your fuel mileage. When you approach a red light or stop sign, remove your foot from the gas pedal well before the intersection. Allow the engine to decelerate the vehicle for several seconds, then gently apply the brakes for the final stop. This not only conserves fuel, but your brake pads as well.

Driving slowly within reason will definitely leave you with more money in your pocket due to reduced fuel consumption and will also contribute to the longevity of your vehicle. Two worthwhile assets in this day and age.

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