Interstate 675 (Georgia State Route 413) provides an alternate route to I-75 northward from Stockbridge in Henry County to the Perimeter Highway (I-285) in southwest DeKalb County. The freeway doubles as a commuter route for unincorporated suburbs in Clayton County while serving redevelopment of Fort Gillem to the west. I-675 appears rural with a wide median and only four lanes north from I-75 to the Double Bridge Road overpass, and six lanes from Forest Parkway north to I-285.
Road work scheduled for 2023 will modify the exchange joining Interstate 285 with Bouldercrest Road into a parclo interchange. Associated work adds a new distributor roadway from Bouldercrest Road to Interstate 675 south, separating weaving traffic movements from the Perimeter Highway westbound mainline.
Interstate 675 was originally planned to be part of a longer route, as part of a proposed I-475 / State Route 400 freeway that would have extended north of I-285 through the east side of Atlanta. The route was envisioned to run to the south end of U.S. 19/SR 400 (North Fulton Expressway) at I-285 in Sandy Springs. The northern third of this highway was constructed as the tolled extension of SR 400. The remainder between I-285 in DeKalb County and I-85 at Lindbergh in Atlanta was never built.
Interstate 675 was applied to the route between I-75 at Stockbridge and I-285 in DeKalb County as approved by the American Association of State Highway and Transportation Officials (AASHTO) on June 17, 1975. Construction of I-675 commenced in December 1982, but was halted when a subcontractor defaulted on work in 1985, resulting in a new bidding process and other complications. These events delayed completion of I-675 until October 30, 1987. The freeway cost $61.6-million to complete.1