Road Worrier

Idling engines waste gas

But when is it worthwhile to shut the engine off?

Staff WriterAugust 5, 2008 

Good grief. Another red light. Georgia Kebschull and her husband, Harvey, hate wasting their time at Raleigh's red lights.

And wasting their gas.

When they're stuck on Gorman Street in the left-turn lane for Western Boulevard, they know they'll be waiting a few minutes for that green arrow.

So Harvey reaches for the ignition key and switches off the engine. Right there in the middle of the street.

"That is such a long light," Georgia Kebschull said. "Sometimes we wait two or three minutes there. So we turn the ignition off -- and then start it up again when the light changes."

She's pretty sure this a good idea. But she has heard conflicting advice.

After all, our cars get zero miles per gallon when they aren't moving. Every list of fuel-saving tips we read these days includes this pearl: "Avoid excessive idling."

Gee, thanks for that wisdom, AAA and EPA. The real question is: How much idling is excessive?

Do we waste more fuel if we restart the car -- or if we let the engine purr for a few minutes?

"We've read it both ways," said Kebschull, 72.

The Road Worrier has petitioned for a ruling from scientists at the Oak Ridge National Laboratory, curators of the EPA's Web site. Meanwhile, the prevailing wisdom seems to support the Kebschulls:

* Don't let your car idle for more than a minute.

* Switch it off. Restart it when you're ready to move.

* Don't idle in the drive-through line. Park the car and walk inside.

* And don't sit there idling in the parking space, either. Turn it off before you straighten your necktie, adjust your mascara, check your messages.

Hybrid fuel-electric cars and buses switch off automatically when they stop in traffic. It's one way they save fuel.

In the old days, our cars had carburetors that wasted gas every time they started. Now, we drive with computer-controlled fuel injectors that are engineered to provide just the right amount of fuel.

"Stopping longer than a minute? Shut 'er down," says Edmunds Inc., which publishes automotive advice for consumers.

Edmunds drove two cars for 10 miles, making 10 stops for two minutes each time. The car that was left idling burned more gas than the one with the engine switched off and on 10 times.

Consumer Reports ran tests and advised readers: "As a rule, turn off your engine if you expect to sit for more than about 30 seconds."

That's good to know. But it doesn't solve the Kebschulls' larger problem with Raleigh's traffic signals.

Lots of red

Each morning, the Kebschulls drive to the Meals on Wheels office near the Farmers Market, where they pack lunches for other volunteers who deliver them to elderly and disabled folks across Wake County.

They're concerned because the price of gas has forced some Meals on Wheels volunteers to drop out.

"Especially in this age of high-price gasoline, we really can't afford to waste untold gallons at intersections where there's little or no cross traffic," Kebschull said. "The idling cars pollute the air so much, and so unnecessarily."

Raleigh motorists see red at intersections all over town, not just on Western Boulevard.

Road Worrier readers have complained about needless delays at traffic signals on Falls of Neuse Road, Glenwood Avenue and Capital Boulevard. Frequent targets for criticism are the streets around Cameron Village.

"Cameron Village is an area we've avoided for years," Kebschull said. "Many of us hate the block-by-block stop-and-crawl. I avoid the merchants there. I don't go through there very much."

She and Harvey see more green lights in Cary, where the town modernized its traffic signal network a couple of years ago.

Raleigh is playing catch-up with Cary. A $28 million rebuild for the city's outmoded signal network is to be completed by the end of 2011. In November, Raleigh will award the first of several contracts to replace brittle copper with 185 miles of fiber optic cable connections to new traffic control hardware at 585 intersections.

Meanwhile, city traffic engineers say they have made signal improvements in recent months to speed the flow along parts of Capital Boulevard, Glenwood Avenue and Creedmoor Road. Last week they were working to quicken the pulse of traffic on U.S. 401 South.

"With gas prices where they are, we're all a lot more conscious of this," said H.P. Humphries, Raleigh's traffic signals manager. "We want to try to move it as safely and efficiently as we can."


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