City officials yesterday embraced the concept of bicycle sharing as a way to reduce traffic and pollution, but said many questions must be answered before Philadelphia becomes the first U.S. city to institute public pedaling on a large scale.

Whether the city would have to fund the program with public advertising is at the top of the list. Where stations would be placed, how big the fleet of bicycles should be, and who would be in charge follow closely behind.

These questions were presented in a hearing before City Council's joint committee on the environment and transportation yesterday. Rina Cutler, deputy mayor for transportation, told the committee that the city's yet-to-be-hired pedestrian and bicycle coordinator would work with the cycling community to develop a business plan.

Washington will become the first city in the nation with a public bike-share program starting this month. But that program, with Clear Channel Outdoor advertising as its sponsor, will deploy 120 bicycles; Philadelphia would need at least 1,000, according to a company that runs similar programs in Europe.

They work like this: For an annual or even daily fee, users receive a pass giving them access to a fleet of bicycles, locked in place at stations throughout the city. The pass allows users to unlock a bicycle, ride it to another station, then slip it back into its docking station for the next user.

Similar programs have caught on wildly in France, especially Paris and Lyon, where University of Pennsylvania student Brittany Bonnette lived for a year and returned to write her thesis on implementing such a program in Philadelphia.

Bonnette said the public-use bicycles in Lyon were her primary mode of transportation, and cost her almost nothing beyond the annual fee of 20 euros (about $31).

"Public-use bicycles can succeed in Philadelphia, providing the world with a role model for a North American sustainable city," Bonnette said.

The initiative has been peddled by community activist Russell Meddin, who told the committee that public-use bicycle programs have "changed urban transportation in cities all over the world." It is also supported by the Bicycle Coalition of Greater Philadelphia and the Bicycle Club of Philadelphia.

In many cases, funds to run the bicycle systems are incorporated into contracts for public furniture - bus shelters, benches, newspaper stands, restrooms - but that can test the public's appetite for street advertising, Cutler said.

One model would have a nonprofit in charge, much like PhillyCarShare, which created the world's largest regional car-sharing program here, and which supports the bike-share program. Companies with bike-share programs in Europe - Cemusa, Clear Channel and JCDecaux - made presentations yesterday.

Clayton Lane, cofounder and deputy executive director of PhillyCarShare, urged Council to "champion" a study, with an eye toward establishing a program within a year.

Councilwoman Blondell Reynolds Brown, who supports the concept, said the city would take a "slow walk" forward with the program.