Squeezing gas for the very last mile

AAA agrees: Driving too slowly is dangerous.

“The optimum speed for saving gas is probably 55 or a little above that right now, so the thought that you’re saving more gas by driving 50 or 45 on high-speed roads isn’t accurate,” said Lon Anderson, a spokesman for the Mid-Atlantic chapter of AAA. “And it’s very, very dangerous.”

Just as bad are drivers who tailgate big rigs, fueled by some obsessives’ intricate calculations of how much more efficiently their cars run when they putter along in the draft and don’t have to fight wind resistance.

Those calculations do show impressive gains in mileage. But safety experts, police and legitimate hypermilers agree that the boost isn’t worth the danger.

“Following a tractor-trailer too closely, you don’t have the ability to see beyond it as you would when following a passenger vehicle,” said Trooper William Tate, a spokesman for the Connecticut State Police. “You’re risking your life and the lives of motorists behind you.”

Cleanmpg.com — where Gerdes, the godfather of the hypermiling movement, is the administrator — warns that drafting is “both a dangerous and rare practice among hypermilers. It’s received a disproportionate amount of publicity in the media. Cleanmpg does not endorse drafting!”

Other techniques — exhaustively studied by enthusiasts in driving forums and on hypermiling Web sites, but dangerous when they leave the realm of theory for the open road — include:

• Overinflating your tires. The idea here is that “if you overinflate your tire, you have even less tire surface on the road,” said Rolayne Fairclough, a spokeswoman for AAA of Utah. That reduces rolling resistance on the pavement and thus improves mileage. But it also “makes it more difficult to handle your vehicle, and it wears your tires out faster,” she said.
• Turning off your engine at stops or coasting in neutral. “Any time that your engine is off or you’re out of gear, you have the loss of an ability to use the engine or the power to pull yourself out of a collision should something come up,” said Roybal, the Colorado driving instructor.
• Rolling through stops. Speeding up and braking use power; the less you use the accelerator or the brake, the less fuel you burn. But Tate, the Connecticut trooper, said that besides being illegal everywhere, the practice is “extremely dangerous” — most accidents on secondary roads are caused by drivers who don’t obey stop signs or traffic lights.

The better idea, safety experts and police say, is to leave the quest for 100 miles per gallon to the experts. Stick to the tried and true mileage boosters: keep up with routine maintenance, ensure that your tires are properly inflated, keep unnecessary weight out of the car and drive at the posted speed limit.

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