Speed and fuel Economy

Idling is a common practice that is detrimental to the environment, fuel economy and the very health of your car. Here are some reasons to avoid it:

It’s a common myth that your car needs to be warmed up before driving, but this is not true. Cars don’t really need to be warmed up unless the weather is below 25 F/-4 C. Even if the weather’s below 25 degrees, it only takes 30 seconds for your engine to be warmed. Actually, driving your vehicle gently is the best warm up for the engine. Other components like wheel bearings, steering, transmission and tires also need to be warmed up. The only way to warm up the other components is to get the car moving.

Excessive idling can damage the engine.

Idling causes damage, because an idle engine is not operating at its peak temperature, therefore fuel combustion is incomplete. As a result, fuel residue can condense on cylinder walls, contaminate oil and damage engine components. Idling can also cause water to condense in the vehicle’s exhaust, which can lead to corrosion and reduce the life of the exhaust system. It’s better to shut your vehicle off and restart, than to let it idle.

Your fuel efficiency also depends on the way that you drive.

A vehicle that accelerates quickly then slams the brakes will have a very low efficiency compared to a vehicle that starts and stops gradually. It’s the equivalent to a human jogging vs. a human sprinting: the tortoise and the hare.

It is a common understanding that cars get much better gas mileage while travelling at highway speeds.  This is mostly true, however, all vehicles have a tipping point, usually between 55- 60 mph or 88 - 96 km/h, when each added bit of speed lowers their fuel efficiency.

According to the U.S. Department of Energy (DOE), as a rule of thumb, each 5 mph (8.0 km/h) you drive over 60 mph (97 km/h) is similar to paying an additional $0.30 per gallon for gas. That being said, cars travelling at their optimum speed (which usually happens to be quite close to the speed limit) can be even more fuel efficient by using cruise control.

A car performs best when working at a constant level, so cruise control can give you great fuel saving, especially on flat terrain.  In hilly terrain, it is sometimes better to avoid cruise control and allow the vehicle to driver slower up hills and faster down them.