Iowa Code Title VIII. Transportation [Chs. 306-330B] § 321.322. Vehicles entering stop or yield intersection

1. The driver of a vehicle approaching a stop intersection indicated by a stop sign shall stop at the first opportunity at either the clearly marked stop line or before entering the crosswalk or before entering the intersection or at the point nearest the intersecting roadway where the driver has a view of approaching traffic on the intersecting roadway before entering the intersection. Before proceeding, the driver shall yield the right-of-way to any vehicle on the intersecting roadway which has entered the intersection or which is approaching so closely as to constitute an immediate hazard during the time the driver is moving across or within the intersection.

2. The driver of a vehicle approaching a yield sign shall slow to a speed reasonable for the existing conditions and, if required for safety, shall stop at the first opportunity at either the clearly marked stop line or before entering the crosswalk or before entering the intersection or at the point nearest the intersecting roadway where the driver has a view of approaching traffic on the intersecting roadway. After slowing or stopping, the driver shall yield the right-of-way to any vehicle on the intersecting roadway which has entered the intersection or which is approaching so closely as to constitute an immediate hazard during the time the driver is moving across or within the intersection.