NEW YORK (AP) — The nation’s biggest bicycle-sharing program got rolling Monday, as thousands of New Yorkers got their first chance to ride a network billed as a new form of public transit in a city known for it.

Suraf Asgedom pedaled along a lower Manhattan street on one of the royal-blue, quick-rental bikes, headed for a gourmet supermarket that’s usually a 25-minute walk from his apartment. The medical executive doesn’t own a bicycle because it’s a hassle to haul one downstairs, find a place to lock it up on the street and worry about it, he said.

“This just makes it much more convenient,” said Asgedom, 39, who plans to use the bike system to get to work at a downtown hospital.

The privately financed program — called Citi Bike, after lead sponsor Citigroup Inc. — kicked off with 6,000 bikes at more than 300 stations. Plans call for expanding it to 10,000 bikes docked at 600 places in Manhattan, Brooklyn and Queens. Riders now can unlock the three-gear, cruising-style bikes from any station, take them for 45-minute rides and return them to any rack.

“We now have an entirely new transportation network without spending any taxpayer money,” Mayor Michael Bloomberg said at a news conference.

One of more than 500 bike-sharing systems around the world, New York’s is the biggest in the United States. Fifteen thousand people already have signed up for New York’s program, city Transportation Commissioner Janette Sadik-Kahn said.

While many New Yorkers already do without cars, Bloomberg’s administration has added hundreds of miles of bike lanes and promoted cycling as a healthy and environmentally friendly alternative to driving. Officials see bike-sharing as a big next step.

So do Mick and Victoria Patterson, who took a look at a lower Manhattan Citi Bike station Monday and plan to sign up. They split their time between New York and Los Angeles.

“We really need to be rethinking the use of the automobile, and this is part of it,” Mick Patterson said.

The bike-sharing rollout has hit some bumps. The launch was delayed because of problems including damage from Superstorm Sandy, and a woman made off with one of the bicycles Sunday evening as workers unloaded them at a Manhattan station, police said. Bloomberg said the bike was recovered. Police were looking for a suspect.

Some residents are incensed about the bike stations, saying the racks block entrances to their buildings or take up park space for a profit-making program. The city intends to split any proceeds with NYC Bike Share LLC, a company running the program. Citigroup is paying $41 million to sponsor it. MasterCard is paying an additional $6.5 million.

“We’re not against the bikes — we’re against them in our park,” said Lora Tenenbaum, one of the sign-carrying critics who came to Bloomberg’s news conference. They want a bike station in Petrosino Square, a small park, to be shifted to a sidewalk across the street.

Some racks have been shortened or moved, including one in front of a Greenwich Village apartment house where owners sued the city over it. Some of the rack was removed last week to create a gap in front of the main door.

Still, resident Deborah Stone worries that the remaining bike rack could make it difficult for emergency vehicles to pull over near the building.

“It doesn’t belong there,” she said by phone.

Officials say they held 400 community meetings to decide where to put the racks. And Bloomberg noted that New Yorkers have long had to work around parked cars and other curbside obstacles.

“We have a busy city,” he said, and “we like that. That’s good.”

Citi Bike subscribers pay a $95 annual fee for unlimited rides of 45 minutes. Starting June 2, riders also will be able to buy a 24-hour pass for about $10 and a seven-day pass for $25; both allow for an unlimited number of 30-minute trips. The usage time is logged when a bicycle is returned to a dock, with additional charges if the bikes have been out past the allotted time.