Deb Gartner was looking down the barrel of an empty nest a few years back when she started trying on hobbies.

Her friends introduced her to their pastimes, but Gartner, 51, said she found that each endeavor made her blood pressure rise instead of fall.

Nearly 30 years after her first trip to the Sturgis bike rally on the back of her college boyfriend's motorcycle, Gartner said she realized her empty-nest bliss might be found on the back of a bike -- but this time, she'd be in the driver's seat.

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"There's no stress in it. You can plan a little trip for the day. The smells, the scenery -- it's an uplifting time for me. Whereas golfing -- it's stressful. Tennis is the same way. It was more like work than something that was a hobby," Gartner said. "I got to keep moving. I'm an excitement junky."

Gartner is one of the women the motorcycle industry said is growing the ranks of riders faster than any other demographic. According to the 2003 Motorcycle Industry Council Owner Survey, women make up nearly 10 percent of motorcycle owners -- a 36-percent jump in the number of overall owners since the council's previous survey in 1998. The median age for female motorcyclists is 42 -- 60 percent are married, 28 percent have a college or post-graduate degree and 35 percent are in a technical or professional career.

Dave Halen teaches Rider's Edge classes at the Harley Davidson dealership in Omaha, Neb. He said he's seen his 12-person classes go from having maybe one woman in 1992 to reaching parity with the men in recent years.

"I do hear from a lot of women that they really are tired of riding as a passenger and they want to go on their own," Halen said. "I'd rather teach women how to ride. They're more demanding, but they're more thoughtful and you don't have ego to get past."

Halen said he's seen a few timid women in class who clearly did not choose to be there. He said they may have been signed up by an overzealous husband or boyfriend, but for the most part, the women are gung-ho and ready to ride.

Harley may be signing up more female trainees because the company has gone out of its way to attract them. In October 2004, the Harley Davidson Web site launched a section just for women, filled with celebrity and "regular girl" rider profiles, a history of women on motorcycles and a step-by-step guide to getting started.

"We definitely think that there's a huge market and thousands of women who have that adventure gene," said HD spokeswoman Leslie Prevish. "We want to be able to give them the information and the inspiration to take the next step."

Harley Davidson said 12 percent of its new motorcycle buyers are women right now, up from 4 percent in 1990. Since fall 2006, the company has bought ads in Glamour, Vanity Fair, Self, Allure and Jane magazine that feature, among others, Bravo television's Jackie Warner. As part of her compensation, Warner got a Sportster valued at $9,636.99, Prevish said.

Sportsters like Warner's are the first Harley some women buy, according to spokeswoman Leslie Prevish.

"We realize that some women think there's a financial barrier to owning a Harley-Davidson. But the Sportster starts at $6,595 with payments as little as $99. It is affordable," Prevish said.

At Suzuki Motorcycles, there's no special focus on females, according to company spokesman Glenn Hansen, but 12 percent of its buyers are women, too.

"Anecdotally, what we think we know is that women motorcyclists don't want to be called women motorcyclists. They just want to be motorcyclists. They don't want a women's motorcycle," Hansen said.

One area where Suzuki is appealing just to females is in accessories. Riding and casual apparel for women is new to the product line, Hansen said, but it is growing by leaps and bounds.

"Sales are strong enough that they are going to expand the offerings soon, perhaps even offering motorcycle helmets with graphics and colors that might appeal more to women riders," Hansen said.

At Omaha parts and accessories retailer DSR Power Sports, Chad Lewis said he's seen manufacturers including Fox, Thor, Icon, Alpine Star, HJC helmets and Shoei stock his shelves with more and more products for women.

"It's getting a lot bigger. (Manufacturers) never used to put the pinks, the purples, the light colors into the helmets and such," Lewis said.

Lewis said he thinks about half of female customers are drivers and the other half ride as passengers.

Clubs have sprung up across the country to nurture and accommodate women drivers. There are Women on Wheels chapters across the United States. A local chapter called Nebraska Women Cruisers regularly rolls by the dozens to bike events across the country, according to past president Kathy Thornton.

"My first long trip was to Kentucky for a Women on Wheels conference. We were quite a sight. Got a lot of attention from guys," said Thornton, who has been riding for 11 years and helped found the Nebraska chapter.

Thornton's group has about 50 members ranging in age from upper 20s to upper 50s. She said the bikes they own run the gamut, but tend to be lower, somewhat less-powerful machines, and most are cruiser-style vehicles as opposed to dirt bikes or sport bikes.