The city took a tentative step this week toward fulfilling the dream of a certain kind of urban idealist, saying that it will explore the possibility of creating a bike-sharing program that could make hundreds or even thousands of bicycles available for public use.

“This is a really big deal,” said Wiley Norvell, a spokesman for Transportation Alternatives, an advocacy group for cyclists, pedestrians and transit riders. “In the realm of things you can do to boost bicycling in a city, bike-share is at the top of the list.”

The city asked companies and organizations interested in running a bike-sharing program to provide assessments of how it could work.

A similar program was started last year in Paris, using thousands of bicycles. A program with 120 bicycles was started earlier this year in Washington.