As a resident of the area, I think there are some inaccuracies on this page.
The scenes from "A New Day" were almost certainly on Interstate 75/85, aka The Downtown Connector. The scenes of downtown were too close and distinct for it to be after I-75 and I-85 separate, and some signage seen indicates them approaching GA-166 from the north, which would definitely place them before the split.
In "Days Gone By", Rick was almost certainly on GA-85 and not I-85. These are two separate roads. I-85 runs SW-NE through the Atlanta metro and is controlled access the entire way. There are no traffic lights or gas stations directly on the road. GA-85 is a state highway that begins in the southern metro at the interchange between I-75 and I-285. It is the primary access to the city for people in the south central suburbs. It run through Forest Park, Riverdale, Fayetteville, Senoia, and eventually, Woodbury. If King County is located anywhere in area S or SSE of Atlanta (as seems to be the case), it would have been GA-85, not I-85 that Rick would have been travelling on.