the core of Atlanta, which is under development in stages as a multi-use trail. Using existing rail track easements, it aims to improve not only transportation, but to add green space and promote redevelopment. There are longer-term visions for streetcar or light rail lines along all or part of the corridor. Bus Georgia lacks a united bus system and is instead, served by various separate systems that serve various areas of the state. Roads and freeways Interstate highways The state of Georgia has of Interstate Highways within its borders. Georgia's major Interstate Highways are Interstate 16 (I-16), I-20, I-75, I-85, and I-95. Other important interstate highways are I-24 and I-59. I-285 is Atlanta, Georgia's perimeter route and I-575 connects counties in North Georgia to I-75. The Georgia Department of Transportation maintains only 16% of the roads in the state. The other 84% are the responsibility of the counties and cities; 75% of those roads are county roads. All of Georgia's Interstate highways are as follows: U.S. highways The state of Georgia has an extensive system of U.S. Highways. All of Georgia's U.S. Highways are as follows: State routes The state of Georgia has an extensive system of state routes. Bridges and tunnels The Sidney Lanier Bridge is a cable-stayed bridge that spans the Brunswick River in Brunswick, carrying four lanes of US 17/SR 25. The current bridge was built as a replacement to the original lift bridge which was twice struck by ships. It is currently the longest-spanning bridge in Georgia and is tall. It is also the 76th-largest cable-stayed bridge in the world. It was named for poet Sidney Lanier. Each year (usually in February), there is the "Bridge Run" sponsored by Southeast Georgia Health System when the south side of the bridge is closed to traffic and people register to run (or walk) the bridge. The Chetoogeta Mountain Tunnel refers to two different railroad tunnels traveling through Chetoogeta Mountain in the northwestern part of the state. The first tunnel was completed on May 7, 1850, as part of the construction of the Western and Atlantic Railroad (W & A), the first state road in Georgia. It was the first major railroad tunnel in the Southern United States and is in length. It was renovated in 1998-2000 and is now open to the public as a privately owned historic site. The second tunnel was built from 1926 to 1928