Interstate 75 in Georgia  Interstate 75 (I-75) in the U.S. state of Georgia travels north–south along the U.S. Route 41 (US 41) corridor in the central part of the state, traveling through the cities of Valdosta, Macon, and Atlanta. It is also designated—but not signed—as State Route 401 (SR 401). In downtown Atlanta, I-75 joins with I-85 as the Downtown Connector. The segment from SR 49 in Byron to I-16 in Macon is part of the Fall Line Freeway and may be incorporated into the eastern extension of I-14, which is currently entirely within Central Texas and is proposed to be extended to Augusta. I-75 is the longest Interstate Highway within Georgia. It enters the state near Valdosta, and it continues northward through the towns of Tifton and Cordele until it reaches the Macon area, where it intersects with I-16 eastbound towards Savannah. For northbound traffic, I-475 provides a relatively straight bypass west of that city and I-75's route. After Macon, I-75 passes the small town of Forsyth. The freeway reaches no major junctions again until in the Atlanta metropolitan area. The first metropolitan freeway met is I-675, then followed by the Atlanta "Perimeter" bypass, I-285. It crosses inside the Perimeter and heads north several miles towards the Atlanta city center. I-75 then runs concurrently with I-85 due north over the Downtown Connector through the central business district of Atlanta. After the two Interstates split, I-75 makes a beeline northwest, crossing outside the I-285 Perimeter and heading towards the major suburban city of Marietta. This section of I-75 just north of I-285 has 15 through lanes, making it the widest roadway anywhere in the Interstate Highway System. North of Marietta, the final major junction in the Atlanta metropolitan area is the I-575 spur. I-75 then traverses the hilly northern Georgia terrain as it travels towards Chattanooga, Tennessee. The section of I-75 from the northern I-475 intersection to the I-24 intersection in Chattanooga is one of the longest continuous six-lane freeways in the United States (some segments along this corridor have as many as 16 lanes). Due to recent lane widening in southern Georgia completed in 2011, the only four-lane section of I-75 in Georgia is bypassed by six-lane I-475; along this route there are at least six lanes from the Alligator Alley portion of I-75 in Naples, Florida to I-24 in Chattanooga (with the exception of a four-lane overpass on I-475 over a railroad track in Macon).