and Roswell Roads from two lanes to four plus a road median. The western intersection has been reconfigured so that traffic to and from Johnson Ferry Road − which carries heavy loads of Cobb County commuters across the Chattahoochee River at rush hour − now flows directly with Abernathy to and from the northwest. Additionally, the Roswell Road bridge over I-285 has been widened to add a turn lane in each direction. There had previously been talk of a tunnel under the freeway to bypass the highway interchange altogether, however this proved to be much too expensive. Another state project is the addition of a half-diamond interchange to Georgia 400 on the north side of Hammond Drive, allowing southbound traffic to exit and northbound traffic to enter the highway. (Ramps on the south side were not possible due to the proximity of the 400/285 interchange.) The city's public works department has made improvements in the conditions of roads and traffic signals since incorporation in December 2005. The department has cleaned approximately 1,500 catch basins, striped of roadway, responded to more than 2,000 calls for repair and service, re-timed hundreds of traffic lights to help improve the flow of traffic and reduce automobile idling, and repaved of roads. The 2008 fiscal year saw the creation of the Sandy Springs Traffic Management Center (TMC). The TMC was constructed and began to operate in less than six months. Construction began in February 2008, five cameras viewed traffic along Roswell Road by the end of June. Special features of the TMC include a webpage that allows the public access to real-time traffic conditions and voice-activated controls. By June 2009, 16 traffic cameras are now available and can be viewed online at the city's website. Mass transit The major provider of mass transit is MARTA, which operates a heavy rail rapid transit line and several bus lines through Sandy Springs. The city is served by the Medical Center, Sandy Springs and North Springs stations. The Georgia Regional Transportation Authority also operates express buses from the North Springs station (which has its own ramps to and from 400) to other counties. Pedestrians and cycling Currently the city is limited in multi-use trails, but bike lanes can be found in certain parts of the city. The city is currently working on creating more trails and bike lanes. Currently, the Abernathy Greenway is a popular multi-use trail running