Twelve years after a community bicycle-sharing program faded into oblivion, a new group of local activists is set to give the idea another try.

The color of the bikes is different this time, but the concept remains the same: promote cleaner, healthier transportation by allowing anyone needing a ride to borrow a bike for free and then leave it in a public place for someone else.

The nonprofit White Bike program, which kicks off next week, is a reincarnation of the similar Yellow Bike project that was launched in 1996 in Portland but soon withered away.

On Monday, White Bike organizers plan to place about seven donated bikes at downtown locations. They'll consist of various models, including 10-speeds and mountain bikes, and will carry clipped-on signs identifying them as free for use by the public.

"If you see a white bike, pick it up and ride it. The purpose of the White Bike initiative is to provide an alternate means of transportation and create an opportunity for the community to learn more about the facts and talk about the issues," says John Rooks, president of Dwell Creative, a public relations design firm in Portland that helped organize White Bike.

Unlike the yellow bikes that were left unlocked, the white bikes will be equipped with combination locks whose code is posted at www.whitebike.org.

Helmets are not provided, but organizers recommend that riders provide their own.

"People will be able to use the bikes as frequently as they need. When they reach their destination, they'll leave the bike locked, waiting for its next occupant to unlock it with the universal code. One bike could have as many as 10 to 15 riders a day," Rooks said.