We often read or hear it driving at a speed of 110 km/h on the highway instead of 130 km/h will save fuel, sometimes with an increase of 20% between one speed and another. Is it true or a rumor? First of all, let’s remember what is three main variables affecting consumption car…

Air resistance, motor efficiency and transmission losses

Air resistance already, which grows exponentially at higher speeds. This means that your car has to overcome more drag during acceleration. By reducing speed, you reduce air resistance and, accordingly, fuel consumption. Engine efficiency also matters: engines are generally more efficient at low cruising speeds. At higher speeds, the engine has to work harder to maintain the speed it can lead to an increase in fuel consumption. Finally, at higher speeds there is more energy loss in the vehicle’s transmission, which means that less engine power is transmitted to the wheels. By reducing your speed, you can minimize these losses.

Really up to 20% fuel savings?

But is it true that you save 20% on fuel by reducing your highway speed by 20 km/h? According to measurements in Auto Lab Plus movement from 130 to 110 km/h (with stabilized speed), we can get 1.2 to 1.8L/100km or even 2L. Variable gain depending on the car: limited on the aerodynamic diesel model, noticeable on the large gasoline “slag block”. It is sad, 20% are generally trustworthy. Minus: we waste time and drowsiness looms. Worse, even if it means slowing down, you may be tempted to pull off the motorway to go onto a secondary network, which is much more dangerous! In short, the choice, tastes and colors are everyone’s business…

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