Does Speed Affect Gas Mileage?

The speed that you drive your car impacts your gas mileage. Your gas mileage will increase until you reach your optimal speed and then decrease rapidly.

Optimal Speeds

According to the U.S. Environmental Protection Agency, most vehicles' fuel efficiency maxes out around 60 mph.

Size

An Edmunds test showed savings of about 12 percent by driving at 65 mph rather than 75 mph.

Potential

According to the Environmental Protection Agency, every 5 mph you drive in excess of 60 mph will cost you an additional $.24 per gallon of fuel you use.

Function

Gas mileage decreases at higher speeds because of the increased energy required to overcome wind resistance. According to Exstrom Labs, wind resistance is negligible until you reach 45 mph.

Warning

Very low speeds, as well as long times spent idling, greatly reduce your gas mileage. According to Edmunds, minimizing idling can increase gas mileage by almost 20 percent.

References

• U.S. Environmental Protection Agency: Tips to Improve Gas Mileage
• Edmunds: We Test the Tips
• Exstrom Labs: Gas Mileage