Carter Lake lies conveniently on the shortest, most direct route between downtown Omaha and the terminal of the regional airport (Eppley Airfield in North Omaha). Abbott Drive, the direct link between those two points, passes through Carter Lake on its route and that portion of the road in Iowa is an Iowa state highway, IA 165.

Although this little discontinuous Iowa state highway has no other connections to the outside world except via Abbott Drive in Omaha, it is fully marked by the Iowa Department of Transportation, complete with all of the usual 'state line' signage used by the State of Iowa.

There is no similar signage on the Nebraska side of the state lines. Abbott Drive in Nebraska is only an Omaha city street, not a Nebraska state highway. (Probably confusing travelers as they enter Omaha, Nebraska, then Carter Lake, Iowa, then Omaha, Nebraska again).

Blame the shortest state highway in Iowa, that goes nowhere other than to connect Nebraska on both sides.