HOUSTON -- Note: The following story is a verbatim transcript of an Investigators story that aired on Friday, Aug. 8, 2008, on KPRC Local 2 at 10 p.m.

Local 2 investigates driving techniques that some say saves big money on gas. It's called hypermiling, extreme measures drivers use to eke out every penny they pay for a gallon of gas.

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Video: Local 2 Investigates Extreme Drivers: Amy Davis Reports

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With prices hovering near $4 at the pump, some of you are wondering if hypermiling really works. Investigative reporter Amy Davis took a road trip to find out.

Our experiment is a sort of race, even if it is a slow race.

"The biggest thing with hypermiling is patience. It's a lot of patience," said 26-year-old Jennie Chen.

As a grad student at the University of Texas with a home in Bryan, Chen logs a lot of miles. Out of necessity, she says she was hypermiling before the term was coined.

"I mean, this is really, really easy stuff," Chen told Davis.

Jennie and Davis both drove to Austin and back to find out if Chen's hypermiling tricks will really pay off. The two drove identical vehicles -- brand new Honda CRVs.

Jennie made just one modification. She checked the pressure in her tires before our trip.

"You don't have to overinflate, just properly inflate," she said.

Everything else about hypermiling happens on the road.

"You know basic physics," Chen explained. "You know if you're braking it, you're wasting your gas. If you're gassing it really fast, then you're wasting your gas. And those are the basic premises."

Hypermilers don't believe in speeding. Jennie coasts when she can, either timing the traffic lights or taking routes with fewer lights to avoid stopping.

"You lose so much gas accelerating from a stop. That's one thing I avoid at all costs is having to stop."

Davis, on the other hand, stopped at Buc-ee's about 100 miles down the road.

Davis' average speed was about 70 mph while Chen drove 45 mph.

Oh, and did we mention Chen cut off the air conditioner to save gas?

"Whenever you use the A/C, some people lose two to three miles per gallon," she said.

So how much did she save?

On the way to Austin, Chen averaged 39.8 miles a gallon, making the trip in three hours and 30 minutes.

Davis' mileage to the capitol averaged 27.1 miles a gallon. She arrived in exactly three hours.

On the trip home, Davis also stopped at a drive-through, perhaps the cardinal sin of hypermiling because you're sitting with your engine idling.

Houston's traffic and tollbooths also proved to be a challenge to Chen's driving methods. She says the ideal conditions are "dry, clear, flat and no wind."

Davis beat Chen back to the station by one hour and 10 minutes, but not before one last stop. About 30 miles outside of Houston, Davis had to fill up just to make it home.

Chen arrived with almost half a tank left.

The totals: Chen averaged 41 miles a gallon. The trip cost Chen $29.80 in gas. Davis averaged nearly 26.75 miles a gallon, spending $46.94 for the same road trip.

"These are things that everybody can practice on their own, and it's not very difficult and they're very, very safe," said Chen.

Think you're ready to try a few hypermiling techniques? You can check out the following links to several hypermiling Web sites.

More Information:

www.cleanmpg.com
http://romanreign.com/hypermiling.htm
www.hypermiling.com
Hypermiling: Quest for Ultimate Fuel Economy