Driving More Efficiently
Aggressive driving (speeding, rapid acceleration and braking) wastes gas. It can lower your gas mileage by roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic.1,2
Driver feedback devices can help you drive more efficiently. A recent study suggests that they can help the average driver improve fuel economy by about 3% and that those using them to save fuel can improve gas mileage by about 10%.3
Sensible driving is also safer for you and others, so you may save more than gas money.
| Fuel Economy Benefit: | 10%–40% |
|---|---|
| Equivalent Gasoline Savings: | $0.34–$1.38/gallon |
While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 50 mph.
You can assume that each 5 mph you drive over 50 mph is like paying an additional $0.24 per gallon for gas.4
Observing the speed limit is also safer.
| Fuel Economy Benefit: | 7%–14%* |
|---|---|
| Equivalent Gasoline Savings: | $0.24–$0.48/gallon* |
| * Average savings, assuming drivers are willing to slow down 5 to 10 mph and fuel costs $3.44 per gallon. | |
Hauling cargo on your roof increases aerodynamic drag (wind resistance) and lowers fuel economy.
A large, blunt roof-top cargo box, for example, can reduce fuel economy by around 2% to 8% in city driving, 6% to 17% on the highway, and 10% to 25% at Interstate speeds (65 mph to 75 mph).5
Rear-mount cargo boxes or trays reduce fuel economy by much less—only 1% or 2% in city driving and 1% to 5% on the highway.
If you need to use an external cargo container, removing it when it's not in use will save fuel and money.
| Fuel Economy Benefit: | 2%–17% |
|---|---|
| Equivalent Gasoline Savings: | $0.07–$0.58/gallon |
Avoid keeping unnecessary items in your vehicle, especially heavy ones. An extra 100 pounds in your vehicle could reduce your MPG by about 1%.6 The reduction is based on the percentage of extra weight relative to the vehicle's weight and affects smaller vehicles more than larger ones.
| Fuel Economy Benefit: | 1%/100 lbs. |
|---|---|
| Equivalent Gasoline Savings: | $0.03/gallon |
Idling can use a quarter to a half gallon of fuel per hour, depending on engine size and air conditioner (AC) use. Turn off your engine when your vehicle is parked. It only takes about 10 seconds worth of fuel to restart your vehicle.7 Learn more...
Turning your engine off when your vehicle is parked can save you money. Here are some tips to help you maximize your savings.7
Best Practices
- Limit engine starts to about 10 times per day on average—unless your vehicle is equipped with a start-stop system. Occasionally exceeding this limit should not cause excessive starter wear.
- Assuming 10 starts a day aren't exceeded, any shutdown longer than 1 minute will save money.
- Limit electric accessory use during shutdown, particularly during longer shutdown periods.
- Drive at least 5 miles between start cycles to fully recharge the battery.
If you'd like to promote idle reduction in your area, the Clean Cities and Communities IdleBox Toolkit can help you get started.
| Fuel Cost Savings: | $0.01–$0.03/min. (AC off) |
|---|---|
$0.02–$0.04/min. (AC on) |
Using cruise control on the highway helps you maintain a constant speed and, in most cases, will save gas.
- Thomas, J., S. Huff, B. West and P. Chambon. 2017. Fuel Consumption Sensitivity of Conventional and Hybrid Electric Light-Duty Gasoline Vehicles to Driving Style, SAE Int. J. Fuels Lubr. 10(3):2017, doi:10.4271/2017-01-9379.
- Oak Ridge National Laboratory. 2017. Sensible driving saves more gas than drivers think.
- Institute of Transportation Studies, University of California, Davis. ECODRIVE I-80: A Large Sample Fuel Economy Feedback Field Test
(ITS-RR-13-15). - Estimates for the effect of speed on MPG are based on a study by Oak Ridge National Laboratory (ORNL): Predicting Light-Duty Vehicle Fuel Economy as a Function of Highway Speed, SAE 2013-01-1113.
- Oak Ridge National Laboratory. 2014. Fuel Economy and Emissions Effects of Low Tire Pressure, Open Windows, Roof Top and Hitch-Mounted Cargo, and Trailer (SAE 2014-01-1614). Study results are based on testing with a small sedan, a standard size SUV, a single roof-top cargo box (20" H x 40" W x 50" L), and a single rear-mount cargo tray. Cargo boxes with other dimensions or shapes may have a different effect on fuel economy.
- Based on a fuel economy improvement of 0.33% per 1% reduction in weight as estimated by Ricardo Inc., Impact of Vehicle Weight Reduction on Fuel Economy for Various Vehicle Architectures, April 2008. Our estimate assumes a vehicle weight, including cargo, of 3,200 lbs.
- Argonne National Laboratory. 2015. Stop and Restart Effects on Modern Vehicle Starting System Components – Longevity and Economic Factors.