Alex Fuentes moves bikes to different locations as needed. Capital Bikeshare is expanding in D.C. and adding more bike racks around the city. (James A. Parcell/FOR THE WASHINGTON POST)

Sara Wilson was halfway through her errands Friday when she dropped off her second bike of the day at Union Station.

“I’m probably the only person riding a bike around town with a five-pound rack of lamb in my backpack,” she said, shifting her shoulders in discomfort, “and I don’t think I put it in there right.”

Wilson had used a bike from the Capital Bikeshare program to pedal over to Eastern Market. Lamb in hand, she used another bike for the return trip, leaving it at the bike station on Columbus Circle just up the street from the Securities and Exchange Commission. Later she thought she might use her third bike of the day for a trip to Woodley Park.

“It’s changed my life,” she said as she slipped the bike into the docking station.

Her husband, an avid cyclist, bought Wilson a membership in the bike-share program as a Christmas gift.

“I’ve been scared of biking forever,” she said. “Now my comfort level is creeping up. It’s an easy bike to ride. It handles the road well. It’s definitely not like a sexy thing, but you can ride it wearing a business suit without any trouble.”

With the arrival of spring, more bike docking stations are opening in the District and Arlington, and last week, an additional 25 locations were proposed.

The Capital Bikeshare program now knows its own rush hours — coinciding, not surprisingly, with everybody else’s rush hour. At its peak, bikes are rapidly snapped up from docking stations in neighborhoods dense with younger people — Capitol Hill, Dupont Circle, Columbia Heights and the U Street corridor.

Trucks from Alta Bicycle Share, the contractor that runs the program, buzz around to the downtown office buildings where the bikes end up, collecting them and rushing them back to neighborhoods for the next wave of commuters.

“There have been complaints that people come out and there are no bikes available, and the other issue is that you get downtown to work and the docking stations are all filled,” said John Lisle, District Department of Transportation spokesman. “Hopefully, within 15 to 20 minutes [Alta] moves the bikes out and back to the people who want to use them next.”

The clunky but solid red machines have been crisscrossing the District and rolling to and from Arlington since late September. Yes, people pedaled right through the winter, encouraged by Capital Bikeshare’s Winter Weather Warrior contest. The winner, Robert Solorzano, logged 780 trips in less than 60 days, averaging 13 trips a day — numbers that would make a bike messenger proud. He forged from behind by taking time off work and, on a single day, docking a bike at every one of the 104 stations then active.

More than 300,000 rides have been logged since the program launched Sept. 20, and people were using the bikes an average of 3,000 times a day in mid-April.

D.C. Mayor Vincent C. Gray cut a ribbon for a new bike station outside City Hall last week.

“Capital Bikeshare already has more than 10,700 members, and we are committed to adding more bikes and more stations,” he said.

The program has been made simple to use. Membership costs $75 for a year, $25 for a month, $15 for five days and $5 for 24 hours. Long-term members get a key to unlock a bike from the docking station; short-term members get a five-digit code for the same task. The first 30 minutes of riding are free. Fees kick in after that until the bike is returned to another docking station.

With more than a thousand bikes and more than 100 stations, and with membership growing rapidly, the District and Arlington are pretty pleased with the response. The District, after a successful membership promotion with a social-buying Web site, has 8,707 members. Arlington has 738, and the balance of the 10,727 members live elsewhere. By contrast, bike-crazy Montreal had more bikes to offer and enlisted 10,000 members during the first year of its program.

“Capital Bikeshare’s success right out of the gate has far exceeded our expectations,” said program director Terry Bellamy.

The commuter cycling culture, always a transportation mainstay in Europe, has flourished in the Washington area in recent years. During last year’s nuclear summit meeting in Washington, when many workers were given a day off and everyone was discouraged from driving, because motorcades were roaring all over town, the depth of the cycling option became evident. With streets stripped of most cars, bikes that normally blend fairly invisibly into the street scape seemed to be everywhere.

The growth of bike-only lanes has served to embolden cyclists who might otherwise have feared doing battle with cars and trucks on congested streets. Office buildings in the District and elsewhere, and local governments, have made more bike racks available to those who ride their own bikes.

Sara Wilson said cycling has expanded horizons for her one-car household, and with parking scarce in her Northeast Washington neighborhood, it’s a better option for errands. “Yesterday I got my dry cleaning — there’s never any parking there — and today I got my rack of lamb.”