Capital Bikeshare -- the Washington,D.C.-area bike sharing program -- has long been the darling of the bicycle community as the largest program of its type in America. But in a few weeks, it'll lose that title twice over, when Chicago and New York are both scheduled to launch bike shares of their own that are even bigger.

The move, some observers say, is hugely significant. As of last year, bike share programs existed in nearly 20 cities, with another 20 in the planning stages, according to a Department of Transportation report. Programs like Hubway in Boston and Nice Ride in Minnesota's Twin Cities have garnered much attention. But the forthcoming debut of bike share in two of the country's three largest cities could be a game changer.

“Bike sharing is definitely booming,” says Ralph Buehler, an urban planning professor at Virginia Tech University. “[New York] is this icon for the U.S. It’s showing the future."

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Indeed, bicycle share’s popularity across the country seems to be exploding, in part due to a growing interest in alternative modes of transportation and technological advancements that have made self-service bike rental systems possible through solar powered kiosks and GPS and RFID technology embedded in the bikes. It's a far cry from bike sharing's earliest experiment, a 1965 attempt to scatter white bicycles throughout Amsterdam in hopes that residents would borrow and return them on the honor system (they were eventually stolen).

Both the New York and Chicago bike share systems have long been anticipated and have long been delayed, with original launch dates set for last summer. But finally, it appears, their debut is just around the corner: Divvy, the Chicago program, is now scheduled to go online some time in June, while Citi Bike, the New York program sponsored by Citibank, is scheduled to begin serving riders some time this month.

Chicago will initially install 75 bike stations in June, where they'll be in dense parts of the city, such as The Loop and River North. Installation of stations will continue every few weeks, with the goal of having 3,000 bikes in 300 stations by the end of the summer, and 4,000 bikes in 400 stations by early 2014, says Chicago Transportation Commission Gabe Klein. New York, meanwhile, has even bigger plans: 6,000 bikes at 330 stations initially, with a system that ultimately has 10,000 bikes. To put it in context, Capital Bikeshare -- the country's largest bike share system -- has around 1,800 bikes.

Klein -- who led Washington, D.C.’s Department of Transportation when it launched Capital Bikeshare in 2010 -- says it’s key to start off big when initiating a bike share program. With too few bikes, Klein says, the program would risk being a novelty as opposed to a key part of the transportation network.

Equally important is designing a user interface that's extremely easy for customers to use. “It’s got to be ‘simple, stupid,’” Klein says. “You need to be able to walk up to it as a 12-year-old or an 80-year-old and be able to figure out easily how it works.”

Cities that launch bike share programs also tend to aggressively market and brand the systems so that residents and visitors alike can quickly become familiar with the service. In Chicago, for example, the bikes are colored the same iconic powder blue as the stripes of the city flag. Capital Bikeshare is red and yellow -- the color of the city's popular Circulator buses and forthcoming streetcars.

Generally, the bicycle-share programs in U.S. cities rely on one of three business models: they can be owned and managed by a governmental jurisdiction, a nonprofit, or a for-profit. Those running in big cities tend to be owned by cities themselves. Typically, the jurisdiction pays upfront costs -- often with the help of federal grants -- and owns the bicycles and infrastructure while hiring a private contractor to manage the system. Memberships, usage fees, and in some cases sponsorships help pay the cost of operations and maintenance.

In Chicago, for example, the up-front cost of the system will reportedly be around $19.5 million, but about $18 million of that will be covered by federal grants secured by the city, according to the Chicago Tribune. The city would pay an estimated $7.8 million in operating expenses its first year, with membership and usage fees expected to cover that total.

Klein says the private company operating the system has performance metrics it’s required to meet in order to ensure the system is self-sustaining; after an initial ramp-up period of several years, the program is expected to remain profitable on its own. “It’s an incredible value,” Klein says.

New York has an even sweeter deal than Chicago: the bikes are plastered with Citibank branding, the result of the financial institution’s contribution of $41 million over five years to fund the effort. Meanwhile, MasterCard is reportedly contributing another $6.5 million. The deal is similar to the model in London, where the financial institution Barclays is a $40 million sponsor. Officials in New York have stressed that city money won't be spent on the effort.

In all three of the big U.S. bike shares -- Washington, New York, and Chicago -- the operator of the system is Portland-based Alta Bicycle Share, the biggest provider of bike share services in the U.S.

Transportation officials have characterized bike sharing as a way of easing congestion and reducing pollution while encouraging healthy lifestyles. Meanwhile, bicycle advocates view bike share programs as a way to further their cause of encouraging cities to build infrastructure, such as bike lanes and bike paths, since it re-introduces many people who weren't regular riders to bicycles. “You create the riders who then demand it,” says Virginia Tech's Buehler.

However, it's not entirely clear just how much bike sharing actually reduces automobile traffic. A recent Virginia Tech study, for example, examined the demographics of Capital Bikeshare's "casual" members, who use the service for one to five days and make up the the majority of members. Only six percent of their trips would have otherwise been taken by taxi or personal automobile, suggesting the service might not be playing a huge role in taking cars off the road. Only about half of the system's bike share users have access to a car anyway.

On the other hand, a report from the Mineta Transportation Institute found that 40 percent of bike share users in Montreal, Toronto, Washington, D.C. and the Twin Cities reported a decrease in their own driving as a result of using the service.