The Interstate Highway System
I-80 / I-380 CORRIDOR in IOWA
The four aircraft from Washington landed at Cedar Rapids shortly before 1400. The plane bearing Mr. Hoover's body, was guided to the proper position in the ceremonial area, while the three aircraft carrying the family group and other mourners were parked near the terminal building outside the area.

As the body bearers appeared at the door of the plane with the casket, the band sounded ruffles and flourishes and played "Hail to the Chief." When the hymn "Fight the Good Fight" was begun, the procession reached the hearse and the casket was placed inside. At the same time, floral vans furnished with out charge by local funeral directors were driven to the plane and loaded with the flowers brought from Washington. Police then escorted these vehicles to West Branch so that they would reach the gravesite ahead of the cortege.

The procession left the airfield about 1415 in thirteen limousines also provided by local funeral directors. Moving over State Route 84, US 218, and Interstate 80, the motorcade reached the gravesite a few minutes after 1500.
http://www.history.army.mil/books/Last_Salute/Ch25.htm

October 25, 1964 - Construction of I-380 took 12 years to complete, ending in 1985, so it was not there.
Interstate 80 (I-80) is a transcontinental Interstate Highway in the United States, stretching from San Francisco, California, to Teaneck, New Jersey. In Iowa, it enters the state at the Missouri River in Council Bluffs and heads
east through the southern Iowa drift plain. In eastern Iowa, it provides access to the University of Iowa in Iowa City. Northwest of the Quad Cities in Walcott is the World's Largest Truckstop. I-80 passes along the northern
edge of Davenport and Bettendorf and leaves Iowa via the Fred Schwengel Memorial Bridge over the Mississippi River
 into Illinois. https://en.wikipedia.org/wiki/Interstate_80_in_Iowa
On Map: "West Branch", "Library" and "Home" have links to information.