Yellow Bikes may not exactly be making a comeback, but if City Commissioner Sam Adams' office gets its way, a new and improved bike sharing system may soon be appearing on Portland streets.

Years ago, Portland helped pioneer the Yellow Bikes program—based on a model from Amsterdam, the project aimed to provide Portlanders with bicycles whenever they needed one. Trouble was, the bikes all fell apart, and the ones that were left intact disappeared. Not surprisingly, the program failed miserably.

But the time may be ripe to bring the idea of bike sharing back to Portland. Adams' office has been quietly working on a plan modeled after new programs in Toronto, Ontario and Lyon, France that have built-in hedges against the flaws of the Yellow Bike disaster.

Adams staffer Roland Chlapowski says the plan is still in the early stages, but the ultimate idea will contain some of the elements of both Toronto and Lyon's systems: What separates those two programs from the free, anyone-take-a-bike program that failed here is that a membership is required to use the bikes. The memberships may be free—or so minimal in cost as to not be prohibitive—but will track who is using the bikes.

In particular, Lyon's program avoids the Yellow Bike problems by establishing a relatively complicated system. The bikes—there are currently 1,500 in use—are equipped with tiny electronic sensors that alert city workers to mechanical problems. If the bikes become unusable, they automatically become locked until they're repaired—that way, bike commuters don't inadvertently hop on a dangerously damaged bike.

Lyon is also offsetting the cost of the program by selling advertising rights for spaces on the bikes themselves. A French billboard company pays the city to put advertising on the specially made bikes—paying for the city's costs. Chlapowski says the Portland program could very well incorporate that idea. Even though the city doesn't currently contract with any advertisers, the purchasing department has greenlighted the idea, saying the city is legally free to find advertisers for the bikes.

It's a step away from the open and free idea of Yellow Bikes, but city staffers say the only way that a bike-sharing program can work is if there are enough protections in place to not become yet another failed experiment.