Christopher Haines, dressed in a tie and khakis, snapped the buckle on his helmet Tuesday afternoon. He uses Indego, the city's bike-sharing system, three days a week. The 46-year-old doctor at Thomas Jefferson University Hospital loves taking the bikes for impromptu jaunts.

"It's real good for the city," he said. "It's fantastic."

Less than a month into the program's existence, bike-share officials boast more than 40,000 rides and 3,000 monthly memberships. Anecdotally, people have enjoyed it - save for the occasional empty station.

There are some cases of vandalism and pitfalls of neophytes taking bike rides in the city. But the majority of initial complaints suggest Indego is a victim of its own success.

"It's been very, very well-received," said Aaron Ritz, bicycle programs manager for the Mayor's Office of Transportation and Utilities. "The complaints we hear the most are: 'Where are all the bikes? When are the next stations coming?' "

Rebalancing the stations is a challenge, one that Ritz said would be rectified with more data - and bikes. About 500 bikes are now available; Ritz said the target was closer to 650 or 700.

Three more stations - at 19th and Lombard Streets, Children's Hospital of Philadelphia's campus, and Clark Park in West Philadelphia - will soon open. The next phase, scheduled for 2016, could add 60 stations.

The goal, Ritz said, was to accrue 2,500 monthly memberships in the first month. It took 18 days to reach that number.

Some adjustments were required. After one of Haines' first rides, his bike did not properly lock into the station dock. He was charged for an additional three hours but got his money back.

Others encountered similar problems. To avoid overcharges, Indego now sends an e-mail to users when the bike is returned.

It is too early, Ritz said, to pinpoint recurring safety issues. Bike-share officials have cited studies that show an increase in riders brings a reduction in accidents.

But many of Indego's riders are not regular bikers.

"We recognize people are out there making their own choices," Ritz said, "but we try to steer them to making the right decisions."

The city's 10th annual Ride of Silence to honor cyclists killed or injured in motor-vehicle accidents was Wednesday night. John Siemiarowski, one of the organizers, said bicycle activists need to educate less experienced riders. The more respect bikers give to cars, he said, the more they will receive in return.

"The overall attitude toward cyclists has been improving," Siemiarowski said. "And cyclists are starting to realize they have some responsibilities as well."

He expected between 200 and 300 riders for Wednesday's eight-mile trek, which started in front of the Philadelphia Museum of Art.

Indego stations still elicit quizzical stares from passersby. Haines owns a bike. He purchased an Indego membership for convenience.

He has contemplated moving to the suburbs before.

"This," Haines said, "is one thing keeping me around."

With that, he whisked down Locust Street.

215-854-2928 @MattGelb