The best way to burn less fuel is to buy a car that gets better gas mileage. But our tests with a Honda Accord, Toyota RAV4, and other vehicles show there are ways to save at the pump without buying a new car.
Drive at a moderate speed
This is the biggest fact. You may have to be a little patient, but driving at 55 mph instead of 65 or 75 will save you money. When we drove the Accord at a steady 65 mph, the car's fuel economy dropped from 49 mpg to 42 mpg compared to 55 mph. Speeding up to 75 mph cost the car another 5 mpg. One reason is that aerodynamic drag increases exponentially the faster you drive; it simply takes more fuel to power the car through the air.
Using an SUV in the same test, our RAV4 dropped from 37 mpg to 33 mpg, then to 27 mpg at 75 mph.
Avoid hard acceleration and braking whenever possible. In our tests, frequent bursts of acceleration and braking reduced an older Toyota Camry's mileage by 2 to 3 mpg. Once up to speed on the highway, maintain a steady pace in top gear. Smooth acceleration, cornering, and braking also extend the life of the engine, transmission, brakes, and tires.
Reduce unnecessary drag
At highway speeds, more than 50 percent of engine power goes to overcoming aerodynamic drag. So don't carry things on top of your vehicle when you don't have to. When we installed bikes on a rooftop carrier atop the Accord driving 65 mph, fuel economy dropped a whopping 35 percent, from 42 mpg to 27 mpg. Even the empty rack created enough drag to suck gas mileage down 5 mpg. Adding a wind deflector quieted things down but didn't help the mileage: It dropped 2 more mpg to 35.
Don't use premium fuel if you don't have to
If your car specifies regular fuel, don't buy premium under the mistaken belief that your engine will run better. The only difference you'll see is about 20 cents more per gallon. Most cars are designed to run just fine on regular gasoline. Even many cars for which premium is recommended will run well on regular. We have found that the differences are imperceptible during normal driving. Check your owner's manual to find out if your engine really requires premium or if you can run on other grades.
Minimize driving with a cold engine
Engines run most efficiently when they're warm. And the most effective way to warm them up is to drive! The effects vary. But as an example, driving our city mpg test several times with a cold engine consumed an extra 4 mpg versus driving it as the engine warmed up. Engines also produce more pollution and wear faster when they're cold. When possible, combine several short trips into one so that the engine stays warm.