The District's Capital Bikeshare stations could soon be papered with ads as a new way to help cover costs for the bicycle program.

The city plans to start putting advertisements on the back of maps displayed at its bikesharing stations as early as this winter, which District Department of Transportation spokesman John Lisle said could be "potentially very lucrative."

The city is currently reviewing bids, but Lisle estimates the ad program could bring in several million dollars. The District would get at least $1 million up front on a five-year contract, then a share of every ad that comes in. "It could well pay for all operating costs combined," he said.

The city is already in better shape with the bikeshare system than its current partners in Arlington and Alexandria, before any ads are sold.

The District has the bulk of the stations, with 138 of the 190 racks. It also boasts the most active members, with 82 percent of the annual memberships. And it has the added benefit of tourist attractions that are more likely to draw the casual users who rack up fees with daily memberships and rides longer than 30 minutes.

In the past year, it cost taxpayers $3.5 million to operate Capital Bikeshare in the District, but riders' fees covered $3.75 million, according to the District Department of Transportation. That does not include the administrative costs to run the system, though, or the capital costs of purchasing bikes and installing stations.

Arlington, meanwhile, had $643,000 in operating costs but only brought in $411,000. However the county's numbers do include administrative costs so it's not an exact comparison. Arlington County's commuter services chief Chris Hamilton estimates that without those costs the system covers about 82 percent of its operating expenses. Either way that ratio is better than many other transit systems, including Metro. Alexandria just launched its stations in September so comparable data are not available.

But the bikeshare system cannot have ads everywhere.

Arlington County does not currently allow outdoor ads like those D.C. is seeking. Hamilton said county staffers are interested in changing those rules to allow ads on the bike stations and on bus shelters. Additionally, Hamilton said, the county wants to get a systemwide sponsorship of the bikesharing program the way New York City has done with its Citi Bike program sponsored by Citibank and MasterCard. "We'd love to see it and get the revenue," he said.

But a sponsorship could be challenging as the system expands into other jurisdictions' border and faces varying rules.

The bikeshare system has expanded quickly since its launch in September 2010 and now has some 1,600 bikes and 190 solar-powered docking stations in the District, Arlington and Alexandria. Montgomery County and Rockville are slated to launch stations next spring, while College Park and University of Maryland are also planning it join.