If a car’s tyres are under-inflated, there is more ‘rolling resistance’. This means more energy is needed for the wheel to roll – just as a soft soccer ball will not roll as easily as a properly inflated one.

A vehicle that is out of tune will not burn fuel as efficiently as it is designed to.

A roof rack, ski box or bike rack attached to your car causes more wind resistance. More of the vehicle’s power is needed to overcome this resistance in order to travel at a given speed.

Accelerating in your car uses more energy (and therefore more fuel) than traveling at a constant speed. It is more efficient to brake earlier and more gently. When you drive more smoothly – with less heavy acceleration and braking – you use less fuel.

A car's air conditioning system needs power to work, in the same way a domestic fridge does. This power comes from the engine and increases fuel consumption. Air conditioners can use about 10 per cent extra fuel when operating.
However, at speeds of over 80 km/h, you will use less fuel if you use the air conditioning than if you open a window. Opening a window disrupts the flow of air over the outside of the vehicle, making it less aerodynamic and increasing its wind resistance. The higher the speed, the more wind resistance and therefore the more fuel the car uses.