Driver Technique Matters With Plug-In Hybrids

The U.S. Department of Energy is testing plug-in hybrid cars across the country. Some results are in, and they're not nearly as good as expected. While federal lab tests showed the cars can get more than 150 miles per gallon, in road tests, they only averaged 51 mpg.

Proponents say the real power behind plug-in hybrids is the mind of the driver.

Just ask electric car enthusiast Susan Fahenstock. She owns the Green Car Co. Her shop converted 14 Priuses into plug-in hybrids for the federal test in the Seattle area. She is unfazed by the 51 mpg results.

"There's nothing wrong with the technology," she says. "It's the driver that has to care enough. They have to be trained, and it's very simple training on what they have."

But in the current pilot project, the Department of Energy specifically wanted drivers who weren't trained on how to drive a plug-in car. In the Seattle area test, the drivers are just employees of local governments and public utilities.

"Now, if you buy it yourself, you'll care enough to get 100 miles per gallon," Fahenstock says.

You'll care enough to choose a route that has lower speeds and fewer hills — and to go easy on the gas pedal.

No Lead Feet Allowed

Fahenstock says anyone can learn it. She let me test drive a plug-in Prius.

"Oh-oh. You see that heavy foot right there? You just got the gas motor to come on at 20 miles an hour," she says.

That's a total no-no if you want to get the most miles per gallon. You want to rely on the battery and keep the gas motor off. At 20 mph, there's no reason for it to kick in — unless you have a heavy foot, which, apparently, I do.

"There's no need to just kind of punch it. It'll go," Fahenstock says. "You're really not going to get to your destination any sooner. Why do you need to accelerate so quickly?"

"Pretend there's, like, an egg underneath your foot," she says. "And if you hit it too hard, you're going to crack the egg. Don't feel, like, pressured by the cars around you. There's no peer pressure."

No peer pressure — but what about the freeway?

Resist Highway Peer Pressure

Chris Wiley, who works for the city of Seattle, took me for a ride in one of the plug-in cars.

He merged onto the freeway at 45 mph — and stayed at that speed several seconds longer than most people probably would. It was one of those merges where you enter onto the fast lane.

"There's a lot of pressure out here on the highways to keep up," Wiley says.

And it's not always safe to resist that pressure. Wiley says it's all about striking a balance: You want to drive fast enough that people won't hit you, but accelerate slowly enough to take advantage of the battery.

We went up one of the most notoriously steep hills in Seattle, and we had that freeway acceleration to deal with. It was 45 degrees outside — cooler weather makes it harder for the battery to kick in.

Still, Wiley was able to boast: "We got 85 miles per gallon for the entire trip."

That's a lot better than the average in the federal test.

But not as good as hypermilers — people who compete on message boards to get the most miles per gallon. They know all the stuff Fahenstock and Wiley know. They make snarky comments about the drivers in the federal tests. But maybe not the next time. The Department of Energy is writing up a short manual for test participants who want to learn how to get the most out of a plug-in hybrid car.

And the agency is starting another test project in California where the drivers will volunteer. A DOE spokesman predicts that those drivers will be plug-in car enthusiasts — and that the test will have much better results.

Phyllis Fletcher reports for member station KUOW in Seattle.