May 16, 2017: The original south end of US 218, at US 30, which has always been the Lincoln Highway here (westbound lanes). The four-lane will be shifted very slightly for the new interchange.
Construction on the US 30/218 interchange begins today, changing an original US highway endpoint and a historic Lincoln Highway junction. A bridge will carry 218 over 30, while ramps are constructed in the northwest and southeast corners. A pioneer cemetery and the historic Youngville Cafe will be spared (although I wonder how, or if, Youngville will be open the rest of the year.)
The Iowa DOT says 218 traffic will be detoured on E44 and V66, through Van Horne, to get to 30. While on the map it might seem to make more sense to go through Newhall instead, that way would have a curve in the county road and this one has a regular intersection instead. (Also, it means a left turn onto the two-lane part of 30, instead of the four-lane part, for southbound traffic.)
I would say this means any non-Vinton traffic from/to the northwest to/from 30 would be better off using IA 21.