Every vehicle has its own optimal speed for fuel efficiency, but gas mileage decreases rapidly any time you are driving faster than 50 mph. The faster you drive, the more gas you waste, costing you money.
2. Empty out your car. Hauling around unnecessary items causes your vehicle to use more gas. For each 100 pounds, your miles per gallon is reduced by about 1 percent. So take out those golf clubs, cases of water and other heavy items you've been meaning to clean out of your trunk, they're costing you money.
3. Don't idle. It takes about 10 seconds worth of fuel to start your vehicle, so if you are idling for any longer than that, turn off the motor. An idling car uses about a quarter to a half-gallon of fuel per hour, depending on the engine size and whether you are running the air conditioner, so save gas by turning off the engine.
4. Use cruise control for highway driving. When driving without cruise control, drivers tend to slow down, speed up, then slow down again in a repeating pattern. With each acceleration, more fuel is used to increase speed. Cruise control keeps your car at a steady speed, meaning you are using less fuel on that long trip.
5. Don't put cargo on your roof. Putting a giant square cargo box on your roof might be great for freeing up space in the car, but it wreaks havoc on your fuel mileage because of the added wind resistance. For larger boxes, your fuel economy can be reduced by as much as 25 percent when driving 65 to 75 mph. If you absolutely need the extra space, opt for a rear-mounted box instead, those only reduce gas mileage by 1 to 5 percent on the highway. And if you aren't using it, take it off your vehicle.
Changing a few basic driving habits and how you transport cargo can make a big difference in your vehicle's gas mileage. And the better the mileage, the more money you keep in your pocket.