I-575  Georgia (link)

30.97 miles [1]; from I-75 north of Marietta (Atlanta) to GA 5 in Nelson. Construction started in 1979; opened in 1987. Provides access to the northern Georgia mountains, as well as far-flung rapidly growing Atlanta suburbs ("white flight", Jim K. Georges writes). [2]

I-575 is four lanes throughout; the southern 15 miles were built before the northern half, and drivers will notice the difference in bridge styles. There is talk of widening to 6 lanes near I-75, as well as completing the half-interchange there (no NB <-> SB access).

See also: I-575 (aaroads)

Sources

1. Route Log and Finder List - Interstate Highways, FHWA, Oct. 31, 2002.
2. Georges, Jim K. "I-575, 985." Email to Kurumi, Jan. 26, 1998.