In Iowa, intersection crashes account for 30 percent of severe crashes, with 40 percent of those crashes occurring in rural areas. Rural intersection crashes can be very severe due to the high approach speeds present. Moreover, crashes at rural intersections are frequently a result of failure to yield. As a result, agencies attempt to find countermeasures which encourage drivers to stop and yield appropriately. The objective of this research was to evaluate the effectiveness of stop sign mounted beacons on improving safety. Since it is difficult to conduct a crash analysis in the short-term, measures of effectiveness focused on unsafe driver behaviors and evaluated how treatments affected those behaviors.