Florida (PART 1/PART 2/PART 3/PART 4)
Georgia
Tennessee
Kentucky
Ohio
Michigan
The Alligator Alley toll road between Fort Myers and Miami runs east-west across the southern tier of Florida.
I-175 and I-375 are two short spur routes in St. Petersburg, FL. They connect to I-275, a loop around the Tampa/St. Pete area.
In Atlanta, I-75 and I-85 are multiplexed for a while. This stretch, called the Downtown Connector, is infamous for its bad traffic and a rather confusing split at the northern end.
I-375 in Detroit is the shortest signed 3di.
At the northern end of I-75, the International Bridge connects Sault Ste. Marie, MI to a similarly-named town in Ontario. This is the closest Interstate with a direct connection to the Trans-Canada Highway.