PHOENIX -- With gas prices increasing, more people are trying to squeeze as many miles as they can out of a tank of fuel.

Some have taken up a practice known as hypermiling, using specific techniques to improve their gas mileage. Some of the so-called hypermilers have been known to get more than 100 mpg with a Toyota Prius.

5 Investigates decided to test some of these techniques with the help of Mike McGovern of the Bondurant School of High Performance Driving, but instead of using a Prius, reporter Morgan Lowe drove an SUV.

McGovern, the driving school's chief instructor, is also a hypermiler.

"I'm very aware of what I'm doing today with the vehicle," he said. "I try to manage it really very efficiently so I can get the best gas mileage that I can get out of the car."

McGovern made several suggestions for improving the Yukon Denali's gas mileage, which was 16 mpg at the beginning of the experiment.

First off, McGovern said the vehicle should be well-maintained, with regular oil changes, clean air filters, new spark plugs and tires inflated as high as the manufacturer says is safe.

Additionally, the way a person drives affects fuel economy.

"The harder we're running the vehicle, the more fuel we'll use," McGovern said.

With these suggestions and other tips, Lowe was able to increase his gas mileage to 24 mpg.

Other suggestions for improving fuel economy:

• Watch the tachometer and try to keep the engine's RPMs low
• Accelerate slowly at stop signs and stoplights
• Drive 55 mph on the freeway
• Turn off the engine instead of idling at long red lights
• Turn off the air conditioning