So in the course of trying to save some money on gas this summer, you choose to turn off the air conditioner and open the windows.

While the air conditioner does draw power from the engine, in the end, you may not be saving any gas at all.

According to the Web site MPGPlus.com, turning off the air conditioner in favor of open windows reduces gas mileage because of the aerodynamic effect.

An Edmunds.com study, however, said that the effect on gas mileage in modern cars is minimal, depending on the car being driven. However, the opening the sunroof as well as in the windows proved to drop gas mileage compared to rolling up the windows and turning on the air conditioner.

Beyond keeping the windows rolled up, there are several ways to save money -- and improve gas mileage in you car -- while hitting the road this summer.

Slow Down

According to Environmental Protection Agency research, the miles per gallon your car gets will quickly drop above 60 miles per hour.

In addition to the safety factor of driving the speed limit, the government's study found that for every 5 mph you drive over 60 mph, you're paying an additional 20 cents per gallon for gas.

Driving 60 mph can save drivers between 7 percent and 23 percent on fuel economy, which can translate to between 26 cents and 86 cents per gallon. The study was based on a fuel cost of $3.72 per gallon.

In addition to driving slower, using the cruise control to maintain a constant speed will also save on fuel.

Speeding, rapid acceleration and braking are also killers for gas mileage. The government's study found that you can increase fuel economy 5 percent in the city and 33 percent on the highway, which translates to between 19 cents and $1.23 saved per gallon.

Keep Car Tuned

Beyond increasing the life of your car, there is some fuel savings benefit to getting a tune-up.

Depending on the work that needs to be done -- not to mention how well it's done -- can improve fuel economy by about 4 percent.

More serious repair work, like fixing a faulty oxygen sensor, can save up to 40 percent of fuel economy.

Other repairs are much easier to do, and can still accomplish the goal of increasing efficiency.

Replacing a clogged air filter, which keeps impurities from damaging the inside of your engine, offers a fuel economy benefit of up to 10 percent, or up to 37 cents per gallon.

Properly inflating tires improved gas mileage in testing by more than 3 percent. Under-inflated tires can lower gas mileage by 0.4 percent for every pound per square inch drop in pressure of all four tires.

According to a study conducted by Edmunds.com, a driver with severely under-inflated tires can spend $800 more per year on fuel than necessary.

Keeping tires properly inflated can also keep them lasting longer.

Plan Your Trips

The EPA recommends trying to do as many errands as possible in one trip in order to save time and money.

The government's report said that several short trips taken from a cold start can use twice as much fuel as a longer multipurpose trip covering the same distance when the engine is warm. Trip planning ensures that traveling is done when the engine is warmed-up and efficient.

Staggering your commute to avoid peak rush hours will also aid in saving gas, since you'll consume less fuel by spending less time sitting in traffic.