When fuel efficiency becomes an obsession

Published May 31, 2007

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By Chris Williams

Sauk Rapids, Michigan - The passion that burns in Laurie With isn't visible until she gets behind the wheel of her Honda Civic hybrid - and drives really slowly.

She accelerates gently when the light turns green, and coasts down hills to save fuel. On highways, she stays in the slow lane and watches the big SUVs zoom past.

She said: "When I see someone roar past me, I think, 'They just used enough fuel to last me a week."

She is part of a small but extremely dedicated group of drivers around the United States who call themselves "hypermilers."

They almost exclusively drive hybrid vehicles, and their goal is simple: squeeze every kilometre they can out of each drop of fuel.

Some of their tips are a matter of common sense and could help any driver, especially now, with fuel climbing past $3 a gallon (R5.65/litre): avoid jackrabbit starts, use alternative routes to avoid stop-go traffic, anticipate lights and drive a bit more slowly.

But those are just a start. Hypermilers slightly over-inflate their tyres to cut rolling resistance, seize every chance to freewheel with their engines off, and sometimes "slipstream" like racing cars behind larger vehicles.

Some of these techniques can be dangerous, and some can't even be done in conventional cars.

Lewisville, Texas computer programmer Chuck Thomas (49), gets about 3.13 litres/100km from his hybrid Honda Insight.

"I do as few accelerations and brakings as possible to get up to speed and maintain it," he said. He cruises a bit below the speed limit, avoids lane changes and freewheels to red lights.

Wayne Gerdes runs a web site dedicated to low fuel consumption; he claims to have coined the term hypermiling. He lists a variety of other techniques:

- Park on the highest point of a lot, facing toward the exit, in order to let gravity do the work of getting the car moving.

- Slipstream off the left rear corner of a truck to reduce wind resistance while still allowing the driver to see you. Gerdes recommends following the truck at a gap of about one second; drafting any closer yields eye-popping fuel economy but is too dangerous, he says.

- Use "pulse and glide," where the driver accelerates above the speed limit, then switches off the engine and glides to a speed below the limit.

It's fairly easy with a hybrid, but can be dangerous in a conventional vehicle because power brakes may not work and some automatic transmissions will not go into gear at freeway speeds.

In a petrol-only vehicle, without a lot of practice, "you can wind up killing somebody," says Gerdes says. (It's also illegal in lots of places.)

'Not on the highway'

Honda spokesman Kurt Antonius said the company shared hypermilers' enthusiasm for fuel economy but couldn't endorse some of their techniques.

He said: "It may be great to slipstream on the racetrack, but not on the highway," he said.

Similarly, Minnesota State Patrol Lieutenant Mark Peterson applauded the hypermilers' goals but said that drafting less than three seconds behind trucks and shutting down a petrol engine while driving sounded too dangerous.

None of that dampens hypermilers' enthusiasm. They share tales of achievement, backed by photos of fascia displays, on websites like Gerdes' and

When a hypermiler in Japan reported averaging 2.11 litres/100km in her Toyota Prius another hypermiler responded with a barrage of technical questions about "intense pulses" and a "low state of charge on the battery."

Sunday driving

Those technical considerations seemed far away on a sunny spring day in Sauk Rapids, where With was happy to demonstrate her high-mileage techniques. Hypermiling, it turns out, looks an awful lot like Sunday driving.

With let her car roll slowly down the slope of a parking lot before starting it. She eased away from a stop sign and coasted for several blocks down a slight grade through a leafy neighbourhood.

"You see a little more," she said as a playground slid past. The fascia display showed four litres/100km on a car the EPA estimates should use about five in city-highway driving.

With a rural highway nearly to herself, she let the car glide well below the 80km/h speed limit, saying with a shrug: "No one's behind me."

The fascia display never went above 4.15 litres/100km.- Sapa-AP

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