In Somerville, three of a planned 12 Hubway bike sharing stations are already installed.

The rest of the stations, including those planned for Davis Square, Teele Square, Ball Square and Conway Park, will be installed soon, according to Scott Mullen, general manager of Hubway.

He said Hubway is waiting for parts from the manufacturer, adding it's "a matter of weeks at this point."

In addition to the locations listed above, Somerville is planning to put stations in Wilson Square, Powder House Park, Powderhouse Boulevard, the eastern side of Davis Square and on Highland Avenue. The exact locations of those stations will depend on demand, according to a recent post on the Somerville ResiStat blog.

Somerville's existing Hubway stations are in Union Square, at City Hall and at the intersection of Washington and Beacon streets.

Hubway goes regional

The bike sharing system, in which members can pick up bikes, ride them, and drop them off at any other station, began in Boston last summer, and Hubway is expanding the system to Somerville, Cambridge and Brookline this year.

At the end of this season, Hubway will have 110 stations in those four Boston-area communities, according to Jessica Robertson, transportation coordinator at the Metropolitan Area Planning Council, which is a leading partner in Hubway.

Mullen and Robinson spoke after a ribbon-cutting ceremony held at Somerville City Hall Wednesday morning. The ceremony was part of a "rolling launch party" designed to celebrate the expansion of the system this summer. Similar ceremonies were scheduled for Brookline and Cambridge, and Hubway officials and members rode their bikes from ceremony to ceremony.

In all, the expanded version of Hubway has been funded with a grant from the Federal Transit Administration and contributions from Boston, Somerville, Cambridge and Brookline.

Robinson said the Federal Transit Administration put up about a third of the total costs with a $3 million grant. The other two-thirds of Hubway's cost comes from the four member communities, but each community has contributed in different ways, Robinson explained. For instance, Boston has made contributions with sponsorships,  she said, whereas Somerville has contributed—about $235,000—outright.

Cutting the ribbon

Somerville Mayor Joseph Curtatone spoke at the Somerville ribbon-cutting ceremony, saying, "Somerville has a strong commitment to biking" and that it's one of the top bike cities in the country.

Somerville State Rep. Denise Provost connected bicycling and Hubway to Somerville's so-called "happiness survey," saying, "Bicycling makes people happy."

State Rep. Timothy Toomey, who represents Somerville and Cambridge, also spoke at the ceremony along with Mary Beth Mello of the Federal Transit Administration, Catherine Cagle of the Massachusetts Department of Transportation, Marc Draisen of the Metropolitan Area Planning Council and Alex Epstein of the Somerville Bicycle Committee.

Hubway is a new "mainstream form of transportation," Epstein said.

Cagle said Massachusetts is now the third most bicycle-friendly state in the country.