Boston's Tish Simmons, front, and other cyclists depart Boston's City Hall Plaza Thursday as part of a launch of the state's first bike-share program — Hubway. (AP)

Boston now has its own bike-sharing program.

The new Hubway system allows Bostonians to pick up a bike from one of 61 bike stations around the city and drop it off at a different station when they are done. At least 40 of the stations opened Thursday, and the rest are scheduled to be up and running in the next week.

Hundreds of cyclists attended Thursday’s launch of the program at Government Center, where Boston Mayor Thomas Menino applauded the program as a way to reduce traffic congestion, improve health and help the environment.

“The car is no longer king in Boston," Menino said.

According to the mayor’s office, more than 700 people have signed up for annual memberships to the bike-share program so far.

One of them is 69-year-old Lois Levin of Newton. At her age, she said, it's easier to bike than to walk.

“Because people — as they get older — their feet hurt, their knees hurt, their ankles hurt," Levin said. "And you can adjust a bike so you can really pedal very easily with minimal stress on your joints."

Levin participated in the inaugural ride of the Hubway program Thursday, then rented one of the bikes to trek from Government Center to Kenmore Square. She said the ride took her about 15 minutes.

Boston already has an active cycling community. There are more than 38 miles of bike lanes in the city, which bikers use to run errands and to get to and from work.

Michelle Igbani regularly rides her bike on Commonwealth Avenue. Although she's happy more people may be joining her in the bike lanes once the program gains some steam, pulled over at a busy intersection on her way to work she worried about how newer cyclists will navigate the city's complicated streets.

Hundreds of bikes were set-up outside Boston's City Hall before Thursday's Hubway launch. (Kimberly Adams/WBUR)

“I mean, not everywhere is completely straightforward," Igbani said. "You're more prone to get into an accident.”

Boston Police officer Tommy Yung cautioned new riders to take it easy their first few times out. He does his patrols on his bike year-round, as long as the weather isn’t too bad.

"If you're not an expert on the streets of Boston, you have to be aware of your surroundings," Yung said.

Another concern is how drivers and bikers interact on the roads. Levin says she didn’t have any problems with drivers on her ride from the Hubway launch at Government Center to the bike station at Kenmore Square, although she was cautious.

"Some of the drivers weren't prepared to see that there was someone in the bike lane," Levin said. "They're not fully accustomed to that yet. But they do get out of the way if they see you coming, if they are overlapping the bike lane."

John Colburne is one of those drivers who tries to watch out for cyclists. He's a pipe fitter for G.T. Wilkinsen Company and spends most of his day out on Boston's streets, going to and from repair jobs. He said that he adjusts his driving to the many bikers he encounters.

"Turning corners, that type of thing, somebody cutting in front of you," Colburne said. "It's enough with the pedestrians, now we have to worry about the bicyclists, too."

Colburne said he’s used to sharing the road, but admitted to being a bit wary when he saw the hundreds of bikers at the Hubway launch downtown.

“Mostly because you've got people that aren't really familiar with the neighborhoods getting on bicycles and they could be spinning around, in and out of traffic," Colburne said.

Officer Yung says sharing the road isn’t just about cars looking out for cyclists. Bikers also have a responsibility to be careful, especially to watch out for pedestrians. Some cyclists are careless around pedestrians, weaving around them on sidewalks when walkers or joggers are unprepared for them, Yung said.

The new Hubway bike-share program also requires that users where a helmet for safety while using the bikes.