As road warriors go, Gary Thaller is more math whiz than he is Mad Max.

When he points his Kia Rio toward the Wal-Mart sitting at the bottom of his Pueblo hill, he is intense, but not exactly aggressive. He pushes in the clutch to coast, he looks four stoplights ahead for clues, he never exceeds the speed limit. The only real threat he poses is to the oil companies that want to sell him more gasoline.

Thaller is a dedicated “hypermiler,” one of a growing breed of proud miles-per-gallon geeks who painstakingly hone their driving techniques to lower gas consumption. They buy $160 gauges that tell them their fuel consumption at every second and trade tips on Internet forums. They post their results for all to see, trying to beat the official EPA mileage rating for their vehicle by 30 percent, 75 percent, even 100 percent.

Thaller’s Kia is rated at 26 miles per gallon for city driving, and he’s been hitting 45 consistently.

“I’m trying to hit 50 mpgs,” Thaller said. “I don’t know if this car is capable of it, but I’m trying to get there. It all adds up. It’s kind of a game to get the tenths of a mile up there.”

Some hypermilers are doing it for a greener world or a fatter wallet. Others are just in it as a math-related hobby, like filling out a Sudoku puzzle. Still more love the competition.

“I wish I could say I was green, but I’m not a tree-hugger type,” Thaller said. “I’m a numbers-cruncher type, and the gauge gives me something to focus on. The side benefit is that it makes me a better driver, and that’s probably the biggest thing for me.”

Hypermilers trace their circuitry back to Wayne Gerdes, a Chicago-area nuclear plant worker disgusted by America’s oil dependence in the wake of the 9/11 attacks. Gerdes and his colleagues in conservation hold periodic “races,” where the object is not speed but seeing if they get a Toyota Prius hybrid above 100 miles per gallon.

The zealotry and the careful-driving techniques it employs tend to exasperate spouses and send office mates sprinting away from the water cooler.

“I’ve talked to quite a few people at work who think I’m kind of nuts,” said Keith Donaldson, now maximizing his mileage on a 90-mile commute from Penrose to Colorado Springs and back. “But then that same guy comes back the next day and says, ‘Dude, did you know you can coast all the way from our hill down to the highway?’ ”

The gauges can transmit each user’s up-to-date mileage directly to the Internet, giving them a boastful signature that tells other forum users exactly what they’ve accomplished.

Hypermiling has quickly developed its own lingo as well:

• “Potential parking” means thinking ahead for a parking space that will allow a forward departure or a downhill exit. Thaller will park 40 yards from his Wal-Mart entrance to get a forward-facing space, while Donaldson points his Subaru away from his garage when he returns home at night because his morning trip starts with a half-mile downhill he can glide in neutral.

• “Ridge-riding” means putting two wheels on the right-hand white strip on a highway, especially during rain: the painted line offers less friction than the middle of the lane.

• A “wolfpack” is to be avoided, a packet of cars going too fast, speeding toward every yellow light and generally blocking a hypermiler’s chances to drive smoothly and efficiently.

The hypermilers advocate some extremes, including dumping vehicle weight by ripping out unused items like rear bench seats. Donaldson took the safari rack off his Forester and bought narrower tires inflated to their full pressure, and immediately added 3 miles per gallon to his total.

But the mainstream hypermilers are also quick to disavow dangerous techniques, including drafting and sign-rolling. They felt burned when the American Automobile Association sent out a news release in June attacking some methods as unsafe.

The responsible hypermilers were quick to point out that while cars may indeed save energy by following close behind a tractor-trailer and drafting in the aerodynamic flow, it’s obviously hazardous. Thaller said some hypermilers have been criticized for rolling through stop signs, but the smart ones don’t — and not just because it’s illegal.

“If you roll through, you might have to do something even worse than slow- braking,” Thaller said. Slamming on the brakes or zooming away to avoid an accident will just kill your mileage hopes.

Donaldson has now taken his hypermiling to the logical extreme — cutting out driving distance altogether. He’s throwing a bike in his car and stopping at a park-n-Ride 8.5 miles from his office, lopping 17 miles off the driving.

“I’m saving money, I’m losing weight, I’m getting in shape,” Donaldson laughed. But he can’t give up the car altogether — “If I was riding 90 miles a day, I’d be in the stinkin’ Tour de France.”

Michael Booth: 303-954-1686 or mbooth@denverpost.com

On the Web

A number of websites and forums offer tips on how to increase your gas mileage using common- sense driving and maintenance techniques. Here are a few of the most useful sites:

CleanMPG.com is the location for advice from the original hypermiling guru, Wayne Gerdes. It has plenty of tips and FAQs, as well as ongoing forums for drivers to ask and offer advice.

The auto-information company Edmunds offers a rich archive of fuel-economy tips and news at edmunds.com/advice/fueleconomy/articles .

Another helpful combination of fuel news and driving advice is at autobloggreen.com.

Hybrid fans who really want to geek up their mileage and knowledge should try greenhybrid.com., started by a college student who loves all things Prius and Civic.

