 Paving of the highway was completed in 1930; US 34 was the first road in Iowa to be completely paved.Work began in the 1950s to modernize Iowa's highway system, mostly by straightening and widening the original highways built in the 1930s.By the end of the 1950s and into the 1960s, sections of US 34 were identified as parts of important corridors that required expansion to four lanes.