For Hybrid Drivers, Every Trip Is a Race for Fuel Efficiency

Evan Hirsche averages 43 mpg with his Prius, while Katie Sebastian, shown with her son, Cole, averages 41 mpg. The drivers have friendly rivalry over their mpg scores, fueled by the Prius hybrid's real-time mileage readings. (By Kevin Clark -- The Washington Post)
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"They are as easy to use as a clock," said Mark Prince, a vice president at Ambient. "You just look at them."

Darby, the Oxford researcher, said energy feedback systems made a brief appearance during the 1970s and '80s, but after the oil crisis subsided and the era of cheap gas set in, they hit the shelf. Now that fuel prices are soaring again and consumers are more interested in green behavior, the focus on the displays has come back.

Although other hybrid cars also have mileage displays, the Prius is the one spawning intense rivalry, because of its strong brand as a hybrid-only car. It has dominated the hybrid market and its drivers outnumber all other hybrid drivers combined. Last month, Toyota sold 21,757 Priuses. The next-best-selling hybrid, the Toyota Camry version, sold 6,678.

Instead of being content with the 48 miles per gallon in the city and 45 miles per gallon on the highway -- 2008 EPA standards for the Prius -- some drivers try to find ways to get far more and go to extremes to do so. When Lee Peterson's wife wanted to borrow his Prius, he barked "No." His wife was baffled. He said: "You're gonna screw up my mileage."

Peterson, an Ohio retail consultant and former Jeep driver, had never been interested in mileage. But when he got a Prius, he became fixated with stretching his mileage as far as possible. Peterson keeps track of his mileage the way golfers chart their handicaps. His record back when his wife wanted the car was 57.4 miles to the gallon. But the monitor put him at 58 -- more than double the 27.5 mpg that non-hybrid passenger cars are required to get in the United States. He had a quarter-tank to go.

"I was going to break my record," Peterson said, but only if his wife steered clear of his wheels.

Peterson now tries to avoid a big hill on his way to work. "If I go up the hill, it really puts stress on the car," he said. "That's when you start to do the weird Prius thing. I'm looking at the display, and I'm getting 10 to 15 miles to the gallon."

He didn't think about the hill when he drove his Jeep. "It's just knowledge," he said. "Now I have it. Knowledge is king."

Some hybrid drivers are so infatuated with their mpgs that they call themselves hypermilers and battle with one another down to the tenth of a mile. Tony Schaefer, a Chicago hypermiler, tracks his mpg for every tank, then posts his results online to a Prius chat group. He has done this for four years. A recent tank finished on April 28 got 66.9 mpg.

In the notes section of his results, Schaefer wrote: "First 60+ tank of the season. Was at 67.8 but then bad weather." The tank lasted 14 days. His 12-month mpg average is 60.11, up from 59.79, recorded after the previous tank. His lifetime mpg average is 53.2.

Michael Gomez, an interactive designer in Austin, has started a Web site called Green Interfaces that tracks displays such as the Prius's. "The best interfaces are the ones that make it interesting and fun," he said. "The competitive driving thing some people are doing means they are making a game out of it, and that's a pretty good test for a good design -- do people start to play with it?"

Schaefer described Prius driving as just that: "It's like playing a game against yourself. You want every tank to be better than the tank before."