My boss recently forwarded me an e-mail about the benefits of hypermiling - where you can theoretically eke out an extra 5-15 mpg out of your car by coasting more, shutting off your engine at stoplights, etc.

AAA has heard all these stories and offers up these warnings:

The old saying goes, “If it sounds too good to be true, it probably is.” AAA Utah warns drivers that even if ‘hypermiling’ seems like a great way to improve a vehicle’s fuel economy in a time of high gas prices, it can actually put their lives at risk.

“Although trying to conserve fuel is a positive goal, ‘hypermiling’ is a dangerous way to try to achieve that objective,” said Rolayne Fairclough, spokesperson for AAA Utah. “Unfortunately, some drivers use extreme and sometimes illegal techniques that put themselves, their families, and other drivers in danger.”

The practice of ‘hypermiling’ involves extreme practices where drivers hope to exceed the EPA estimated fuel efficiency of a vehicle by drastically changing their driving and maintenance habits. There are several dangerous ‘hypermiling’ techniques to avoid. They include turning off a vehicle’s engine or coasting in neutral, tailgating or drafting larger vehicles, rolling through stop signs, and driving at erratic and unsafe speeds. Some ‘hypermiling’ motorists will also over-inflate their tires to reduce the tire surface touching the road. This makes tires more susceptible to damage and wear and causes bad handling.

“Drivers need to maintain total control of their vehicle so they can maneuver safely in an emergency,” said Fairclough. “Many ‘hypermiling’ techniques jeopardize safety simply for a potential increase of a few miles per gallon. It’s just not worth your life or someone else’s.”

There are many legal and safe ways that AAA recommends to conserve fuel:

Check tire pressure at least once a month and inflate tires to the vehicle manufacturer’s standards listed in your car’s owner’s manual. Fuel efficiency is reduced by up to two percent for every pound of pressure tires are under-inflated.
Smooth and easy acceleration and braking.
Use cruise control to maintain a steady speed.
Use the lowest grade motor oil recommended by the vehicle manufacturer for a motorist’s climate to avoid engine damage.