Cut Fuel Costs With Everyday Driving Habits

Federal fuel-efficiency research shows simple habits behind the wheel and under the hood can change gas mileage far more than most drivers expect. Here is how to work through them, one step at a time.

Fuel is one of the few driving costs you can cut without buying anything new. Federal fuel-efficiency research shows that how you drive and how you care for the car move gas mileage more than most people expect, and none of the changes below require special equipment. All you need to start is a recent fuel receipt, a tire pressure gauge, and the maintenance schedule in your owner’s manual.

Start With the Number: Your Current Cost Per Mile

Before changing anything, get a baseline. The next time you fill up, write down the price per gallon, the gallons you bought, and the odometer reading. Divide the gallons into the miles you drove since the last fill-up to find your miles per gallon, then divide the price per gallon by that figure. The result is roughly what each mile costs you, and it turns every habit below into a concrete number you can recheck later.

Keep the window sticker figure in perspective. Fuel economy estimates on new vehicles come from five test cycles run in a laboratory, and the EPA adjusts the results for variables the tests do not cover, such as wind, hills, and road conditions. Your own fill-up math usually tells you more about your car than the label does.

Step 1: Ease Off the Accelerator and the Brakes

Aggressive driving, which means speeding combined with rapid acceleration and braking, lowers fuel economy by 15 to 30 percent at highway speeds and 10 to 40 percent in stop-and-go traffic, according to Department of Energy analysis. Researchers at Oak Ridge National Laboratory put a price on it: the lost mileage works out to roughly $0.25 to $1 per gallon.

Three habits do most of the work:

• Coast toward red lights instead of staying on the gas and braking hard at the last second. Fuel-efficiency coaches at vehicle fleets teach drivers this exact move.
• Use cruise control on the highway to hold a steady speed instead of drifting up and down.
• Watch your speed above 50 mph. Gas mileage usually falls quickly past that point, and every 5 mph over it is like paying an extra $0.34 per gallon.

The trade-off is time. Smooth driving can add minutes to a long trip. On the other side of the ledger, hard acceleration and braking wear parts faster, and the Department of Energy notes that driving sensibly is also safer.

Step 2: Check Tire Pressure and Keep Up With Maintenance

Under-inflated tires wear faster and reduce fuel economy. Find the correct pressure for your vehicle on the glove compartment door or the driver’s-side door pillar, and check it regularly.

Maintenance matters just as much. Properly maintained vehicles average about 4 percent better gas mileage, which the Department of Energy values at roughly $0.19 per gallon. Fixing a serious problem, such as a faulty oxygen sensor, can improve mileage by at least 40 percent. Skipping routine work like oil changes can lead to poor fuel economy and may even invalidate your warranty.

Follow the maintenance schedule in your owner’s manual rather than a shop’s own schedule. Some shops call for more frequent servicing than the manufacturer recommends, so ask any shop to explain, in terms you understand, why it suggests extra work. Use the recommended grade of motor oil as well.

Money saver: Keep receipts for oil changes, tire rotations, and inspections. A warranty company can ask for maintenance records, and a claim may be denied if you cannot show the vehicle was properly maintained.

Step 3: Lighten the Load and Clear the Roof

Extra weight costs fuel, and roof cargo costs more. Anything hauled on the roof makes the car less aerodynamic, which cuts mileage hardest at highway speeds. Cargo boxes mounted on the rear are much easier on fuel economy, reducing it by up to 2 percent in city driving and up to 5 percent on the highway.

The trade-off is convenience. You will sometimes need the space. The habit is to empty what you do not need for the trip ahead: sports gear, tools, the box that rides along every day by default. If you use a roof box or carrier, take it off during the parts of the year you do not.

Step 4: Watch Idling and Short Trips

An idling engine burns fuel while covering zero miles. The Department of Energy estimates that idling can use a quarter to a half gallon of fuel per hour. Over that same hour, the North Carolina Department of Environmental Quality puts a typical car at about one-fifth of a gallon of gasoline, while a light-duty diesel truck burns roughly a gallon. Idling for 10 seconds uses more fuel than turning the engine off and restarting it, which is why fleet driving coaches tell drivers to limit idling to 30 seconds or less and shut the engine off while parked.

Warm-up idling is largely unnecessary. A better way to warm the engine, transmission, tires, and other moving parts is to start the car and simply drive off slowly. The stakes add up nationally: Argonne National Laboratory estimates road vehicles lose more than 6 billion gallons of gasoline and diesel to idling every year, worth more than $11 billion annually even at $2 per gallon. Every gallon burned also produces more than 20 pounds of greenhouse gases.

Step 5: Combine Errands and Rethink the Route

Winding, out-of-the-way routes lower fuel economy, so combining errands into one loop beats several separate trips. Plan the loop to cover the fewest total miles, and think about timing too, since crawling through stop-and-go traffic burns more than steady cruising.

Hot weather adds its own choices. The Department of Energy suggests driving with the windows open briefly before switching on the air conditioning, which lets hot air escape the cabin and eases the load on the system. At lower speeds, open windows cost less; at highway speeds, use the air conditioning and keep the windows up.

Step 6: Compare Fuel Prices Without Driving Past Them

Prices differ from one station to the next, but chasing the lowest number has a cost of its own. Before driving across town, compare the per-gallon difference against the extra miles the detour adds, using the cost-per-mile figure from the first section. As an illustration, a detour that burns a few tenths of a gallon can erase a small per-gallon discount entirely.

The cheapest station that sits along a route you already drive is worth more than a bargain across town. If you use a price-comparison app or station signs, weigh what you find against the distance, not just the sticker price.

What Each Habit Is Worth, and What It Isn’t

Habit	What the data shows	The trade-off
Smooth driving	15 to 30 percent better mileage at highway speeds, 10 to 40 percent in stop-and-go	Slightly longer trips
Staying near the limit	Each 5 mph over 50 costs about $0.34 per gallon	Extra travel time
Regular maintenance	About 4 percent better mileage on average; at least 40 percent for a serious fix	Time and repair costs
Rear cargo instead of roof	Rear boxes cost up to 2 percent city, 5 percent highway	Less carrying space
Cutting idling	A car can waste about one-fifth of a gallon per hour parked	Loses cabin heat or cooling while stopped

Two cautions. First, these ranges come from government testing and fleet studies; your results depend on the vehicle, the traffic, and how much you change, so use your own cost-per-mile figure to judge what worked. Second, no single habit transforms a budget. The realistic pattern is several small changes that together trim what you spend at the pump.

The savings from one fill-up can look small, but they repeat every week, which is how small routines become real money. The same arithmetic works elsewhere in the budget: lowering your energy use at home applies steady small changes to utility bills, and round-up savings explains how small automatic deposits work and what they can and cannot do. If money is already stretched month to month, saving on a tight budget covers where to start when almost nothing is left over.

You might be wondering

How much money can smoother driving really save?

Government analysis puts the penalty for aggressive driving at 15 to 30 percent of fuel economy at highway speeds and 10 to 40 percent in stop-and-go traffic, or about $0.25 to $1 per gallon. Your own savings depend on how aggressively you drive now and how much you change.

Does turning the engine off at short stops actually help?

Yes, within limits. Idling for 10 seconds uses more fuel than turning off the engine and restarting, and federal fleet guidance suggests limiting idling to 30 seconds or less. Shut the engine off when you are parked and waiting, and warm the car up by driving off slowly.

Where do I find the right tire pressure for my car?

The EPA’s fuel-saving guidance points to the glove compartment door or the driver’s-side door pillar. Under-inflated tires wear faster and reduce fuel economy.

Should I follow my repair shop’s maintenance schedule?

Follow the schedule in your owner’s manual for your type of driving. Some shops create schedules calling for more frequent servicing than the manufacturer recommends, so ask the shop to explain any extra work before you agree to it.

These tips are general information. Prices, plans and programs vary by provider and location, so check the details with your provider before you switch or sign up.