East of Peosta, US 20 leaves the straight line running from Farley and turns northeast to Dubuque. Fifty years ago, there was a Highway Commission concept to run 20 straight east into Illinois, but budget and topographical considerations ensured it would never be more than a dotted line on a map. The entire portion in Dubuque County is an expressway, meaning there are multiple at-grade intersections.
US 20 intersects Swiss Valley Road as it turns. Swiss Valley Road is a paved connection from US 20 to US 151, even though it’s two-lane and winding. The intersection has been the site of multiple accidents. KWWL reports that plans from 2006 to modify the intersection have been brought up again by the relative of a recent accident victim.