A bicycle-friendly city has always been a good idea. It makes even more sense in an era of $4 gasoline.

Momentum is building for a bike-sharing network in Philadelphia to be used by thousands of commuters daily. It would reduce congestion, save money for workers, and contribute to a healthier city.

Three companies with bike-sharing programs in Europe have made presentations to City Council. Thousands of bicyclists already ride city streets. What's needed is more encouragement from Council and Mayor Nutter, as well as a study of traffic patterns and ridership demand.

Bike sharing would be similar to car-share operations. A private outfit would provide up to 4,000 rental bikes at 250 or more locations. Riders, who pay an annual subscription fee, would receive a swipe card enabling users to unlock a bicycle at a kiosk, ride it, then return it to a docking station. Bike stations would be located near all SEPTA stations. Each time a rider uses a bike, the first 30 minutes are free.

Funds to run bike-share operations typically are tied into contracts for street advertising on public "furniture" such as bus shelters and newspaper stands.

As bike ridership increases, auto congestion would lessen. The city would need to add more bike lanes on streets.

Paul Levy, head of the Center City District, says studies have already shown cycling is a quicker way to cross Center City than driving a car. The time to get to work on this idea is now, not when gas hits $6 per gallon. A pilot bike-share program will start soon in Washington, D.C.

Russell Meddin, an advocate with Bike Share Philadelphia, said a travel demand study would cost about $150,000. That would be a worthy expense for a civic-minded foundation to underwrite.

Rina Cutler, deputy mayor for transportation, has said the city's yet-to-be-hired pedestrian and bicycle coordinator will develop a plan with cycling advocates. Some Council members are being cautious. But bike sharing could become an integral part of Nutter's vision for a "sustainable" city.