Meet Wayne Gerdes, the hero of hypermiling

Some call them crazy. Others call them obsessed. They consider themselves efficient.

They are hypermilers, drivers who use a range of driving and maintenance techniques to improve their gas mileage.

Americans spend about 10 percent of their annual incomes on car maintenance including gas, according to the 2007 Transportation Energy Data Book.

Anybody who can beat the Environmental Protection Agency's fuel-economy sticker on his car is considered a hypermiler, said Wayne Gerdes, who coined the term and created CleanMPG.com. Most drivers are only getting 20 miles per gallon, he said, and he thinks it's "sad."

Part of the issue is that people don't know about the physics of their cars, he said. For example, 80 percent of the tires on the road are underinflated, which hinders fuel efficiency, Gerdes said.

Gerdes, 45, who lives in the northern suburbs of Chicago, provides free driving clinics to drivers who want to improve gas mileage. "Anybody can do this and they are going to be a far safer driver than they were previously," Gerdes said.

During one of his clinics, Gerdes coached a driver of a 2005 Honda Accord — which the EPA says can get 24 mpg — to get more than 48 mpg just by changing the way he drove.

"Our country is in a lot of trouble right now because of this oil addiction," Gerdes said.

The idea for hypermiling dawned on Gerdes the day after the 9/11 attacks, he said. Gerdes, then a nuclear-plant engineer, thought that by using so much gasoline Americans were funding terrorist organizations in the Middle East.

Gerdes decided that by reducing his fuel consumption he would provide less money to terrorists. Once he started experimenting and perfecting his techniques he was surprised at how effective they were, he said.

"I knew by slowing down I was going to save fuel, but I didn't know how much fuel I was going to save," he said.

Eventually, he ditched his Nissan pickup for a Honda Insight, with which he has been able to get 100 miles per gallon. He also hosted online forums on CleanMPG.com to show people how to get more bang for their buck. Soon Gerdes was traveling and providing clinics.

Many drivers become hypermilers because they want to reduce gas costs. Gerdes' own wife didn't heed his hypermiling ways until gas prices rose to more than $3.50 per gallon, he said.

The best hypermiler in a city is a person who uses mass transit, Gerdes said. When a bunch of people are takingMegabus from Philadelphia to New York City for example, it is about 150 miles per gallon per person, Gerdes said. "That bus is tough to beat," he said.

Cathy Rossi, a spokeswoman for AAA Mid-Atlantic, agreed that idling and speeding will reduce fuel efficiency.

However, she warned that some people take hypermiling too far and become dangerous on the road.

"The biggest danger that we have seen with it is drivers who are driving well below the speed limit....If you are driving dramatically slower than other cars on the road, then you are posing a threat to other drivers," Rossi said.

Some "overly enthusiastic" drivers also coast through stop signs without braking and stay close behind large trucks to reduce wind lag — both unsafe practices, Rossi said.

While the pressure listed on the sidewalls of tires shows its maximum pressure, Rossi said, each tire behaves differently depending on the vehicle. So drivers should use the tire pressure recommended inside the driver-side doors. Overinflated tires can burst unexpectedly, she said.

"I think you're going to have to weigh what's safe and what's fuel-efficient....How can I be safe and save money at the same time?" she said.

Gerdes said that many of AAA's reservations about hypermiling are unfounded. "The hypermilers are the scourge of the highway because they follow the speed limit," he teased.