After three years of work, the Alewife Greenway Bike Path project, linking two of Greater Boston’s most prominent pedestrian and bike corridors, was completed last month. The Alewife path travels 2.5 miles through Arlington, Cambridge and Somerville to connect the Minuteman Bikeway and the Mystic River Reservations. The project, which was funded by a $3.6 million grant from the American Recovery and Reinvestment Act, provided work for 49 people while also encouraging alternative forms of transportation, according to state officials. It also included the development of two new public paths that are accessible to the disabled in the Alewife Brook Reservation, the restoration of sections of Alewife Brook, and created pedestrian safety crossings at two major intersections. The majority of the Alewife Greenway path in Somerville and Cambridge is asphalt or boardwalk, while much of the section through Arlington has a crushed-stone surface, said Dan Driscoll, a state Department of Conservation and Recreation official.