Increase Your Gas Mileage

By Joshua Zumbrun
Washington Post Staff Writer
Sunday, August 6, 2006

There was good news and bad news, I learned. The good news: I got a promotion. The bad news: I landed in The Post's Howard County news bureau -- a wonderful spot, but about 35 miles from my front door.

This was last summer. I didn't own a car, the job started in two weeks, gas prices were climbing, and a 70-mile commute (instead of 10 friendly minutes on the Circulator bus) was looking expensive.

The Insight, Honda's two-seater hybrid with amazing gas mileage, sounded almost too good to be true. A lot of reports said it was -- real drivers don't get the numbers Honda touts. (The Department of Energy has a useful site explaining why this is at ) The cars were scarce, so I flew to Wisconsin to become the proud owner of a 2001 Honda Insight, with an estimated 57 mpg in the city, 56 on the highway.

That's where I randomly met Bradlee Fons, an enthusiast of the cars who starts spouting hybrid statistics the moment he introduces himself. He and his son Justin are part of a rare fraternity: hypermilers, people who modify their driving to improve mileage and reduce emissions.

Fons explained that you need to "relearn how to drive" in order to appreciate a hybrid's benefits. After averaging around 48 mpg on my way home -- good, but not what was advertised -- I logged onto and, two sites Fons had recommended to learn the ins and outs of hypermiling. The sites are full of people obsessed with their mileage gauges, people who log their mileage on each tank of gas, even people who photograph the odometer and post it online to show off particularly successful runs.

Fons also suggested I talk to someone he's dubbed "America's greatest hypermiler," Wayne Gerdes. The nuclear power plant operator in Illinois ("producing electricity with zero greenhouse gas emissions," Gerdes observed) averaged more than 90 mpg for more than a year driving a manual transmission Honda Insight. He was part of a team that drove a Toyota Prius for more than 1,200 miles, in two straight days of driving, on a single tank of gas, an effort that was featured in an HBO Earth Day Special "Too Hot Not to Handle."

Gerdes says he has always kept records for every vehicle he's owned. Tired of paying for gas, he started watching the way he drove in his Toyota Corolla, thinking about the physics of driving and experimenting with ways to improve mileage. "I hit 52 mpg in my Corolla and I said, 'Wow, this is pretty special. I bet there's more.' "

Turns out, there's a lot more. And the handful of driving tips that I adopted worked wonders. On a recent drive home from work, I checked the odometer as I coasted across the Key Bridge: 82 miles since leaving home that morning, or 75.6 miles per gallon.

From Georgetown to Columbia, and back -- on barely a gallon of gas.

Want to know more about hypermiling? Join Joshua Zumbrun for an online chat Monday at noon at

Hypermiling Techniques

Hypermiling is all about making adjustments to maximize your gas mileage, and many techniques work whether you're driving a hybrid or a Hummer.

"Anybody can be a hypermiler. It doesn't matter if you're in a Dodge Durango getting 10 mpg today. You can get 15 mpg tomorrow," says Wayne Gerdes. "It's going to save fuel. And this country needs that."

Below are some common hypermiling suggestions -- and an expert's view on whether the technique is smart and safe. We asked auto expert Pat Goss -- owner of Goss' Garage in Seabrook, commentator for PBS's "Motorweek," and host of a regular chat on -- to weigh in on what works.


Expert's take : Goss says that as you go above 38 mph in most cars, you lose mileage. For every 5 mph above 55, he says you can lose as much as 10 percent of your fuel economy. So slowing down can save you gas.

DRIVING WITHOUT BRAKES (or in hypermiling lingo, "d.w.b.") is all about coasting. Congestion is constant in Washington, and accelerating from zero to 20, then back to zero, is inefficient. Instead, if the car in front of you is speeding up, maintain a steady speed and let it get ahead of you, when traffic starts to slow back down you'll catch up.

Expert's take: Do it when possible -- but be careful. "You're probably going to have some highly ticked off people if you do it on the Beltway," Goss warns.

TURN OFF YOUR CAR AND COAST , aka the "forced-auto stop." In hybrids, the internal combustion engine shuts off at stops to conserve fuel; the electric batteries keep the car running. To save even more fuel when decelerating, some hypermilers -- including Gerdes -- shift to neutral and turn off the engine while coasting to a stop.

Expert's take: "Highly dangerous. You don't have your car under control," says Goss. (In other words, not all hypermiling techniques are good ones.)

OPTIMIZE YOUR ROUTE : Avoid big hills or stop-and-go traffic. Test different routes to see which is the smoothest ride. Sometimes, a longer route with better driving conditions uses less gas.

Expert's take: "Basic driving techniques. I teach this the first day," Goss says.

WATCH YOUR TIRE PRESSURE . It takes a lot of extra energy to move even slightly flat tires. Some hypermilers recommend over-inflating tires.

Expert's take: Goss says this works but is very risky. "When you over-inflate a tire, you can compromise its traction and . . . make the tire wear out more rapidly," he says, adding that it could be "very negligent to recommend that someone do that."

STAY ON TOP OF OIL CHANGES , and use thinner oil.

Expert's take: "It can have a significant effect on fuel economy, especially as the oil ages," Goss says. "The viscosity of engine oil is always increasing. . . . The thicker the oil is the harder it is to push through the engine."

-- J.Z.

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