A year ago Alisa Clickenger helped organize a cross-country motorcycle trip for women to commemorate the 100-year anniversary of a most amazing ride by two sisters from Brooklyn, New York.

The Sisters' Centennial Motorcycle Ride honored the exploits of Augusta and Adeline Van Buren, who in 1916 rode motorcycles more than 5,000 miles across the country to prove women could be military motorcycle couriers, able to endure long distances and harsh conditions as well as men.

For Clickenger, it was a breakthrough.

"The ride was important to me," Clickenger said. "It was the realization of a long-held dream of mine to lead a group of women across the United States on motorcycles. Seeing nearly 250 women on motorcycles in my rear-view mirror riding over the Golden Gate Bridge was epic -- something I'll never forget. It was very emotional for me."

The ride also helped Clickenger demonstrate what her fledgling company, Women's Motorcycle Tours, could accomplish.

In this July 2016 photo provided by Alisa Clickenger, Clickenger leads a group of women riders over the Golden Gate Bridge in San Francisco at the end of a cross-country trip to honor two sisters from Brooklyn, N.Y., who made a similar ride in 1916. Clickenger operates Women's Motorcycle Tours, which conducts motorcycle rides that cater exclusively to women, and estimates she's traveled more than 250,000 miles on motorcycles. (Christina Shook/Courtesy of Alisa Clickenger via AP)

"For me, part of riding motorcycles still is the challenge of embracing the unknown, the mastery of machine and also facing my fears and meeting the challenges of an extended motorcycle adventure," said Clickenger, whose company focuses solely on tours for female motorcyclists. "It was the first time I've seen so many manufacturers (Indian and BMW among them) come together for a common goal -- promoting women and motorcycling. It was wonderful."

Women own about 14 percent of registered motorcycles, up from 8 percent in 1998, according to the Motorcycle Industry Council's latest numbers.

But Genevieve Schmitt, founder and editor of the online magazine "Women Riders Now," says those numbers count only new registrations.

She says women comprise nearly 25 percent of those who ride (including passengers), and that makes them major players in the riding business.

"Personally, I feel we've kind of seen an exponential growth in the 11 to 12 years that I've had the site," Schmitt said. "There is a whole new market of young girls in their 20s who have taken up riding that we haven't seen, really, in history."

This March 2017 photo provided by Alisa Clickenger, shows Clickenger posing in front of the Che Guevara Mausoleum, a favored stop for visitors in Cuba. Clickenger operates Women's Motorcycle Tours, which conducts motorcycle rides that cater exclusively to women, and estimates she's traveled more than 250,000 miles on motorcycles. (Courtesy of Alisa Clickenger via AP)

Why are more women taking up motorcycling? Schmitt calls it the "copycat effect. A woman sees another woman riding a motorcycle and says, 'If she can do it, so can I!'"

Manufacturers such as Harley-Davidson produce entry-level motorcycles, but it still can seem "intimidating getting on a powerful vehicle," said Pam Kermisch, a novice rider who works for Polaris, the company that owns Indian and Victory motorcycle brands.

"I did all the classroom stuff. That's one thing, but it's another thing to actually get on and do it. Once you do it, it's very doable. I think for a lot of people, that's the scary part. I think the second piece of it is that in order to get confidence you have to do it more."

Which is where Clickenger, who lives in Diamond Bar, California, but is on the road most of the time, comes in. Like just about everybody who rides a motorcycle, she identifies with the credo that the only way to travel is on two wheels.

In March, she organized an all-female motorcycle tour of Cuba.

That will be followed by the Colorado Backcountry Discovery Route during the last week of July and a tour of the American Southwest in October departing from Las Vegas.

"My company tagline is 'Life-changing experiences on two wheels,'" Clickenger said. "The bottom line is it's about empowerment, and the feeling of freedom -- freedom from our fears, freedom from societal constraints, freedom from our own self-constructed, pre-conceived constraints and breaking those boundaries."