obsolete before it was ever constructed. Construction The first section of I-80 to open for traffic, from the West Mixmaster to the Douglas Avenue interchange in Urbandale, opened on September 21, 1958. By the end of November 1959, the new Interstate extended around the north side of Des Moines to US 69. Within a year, the East Mixmaster, where I-35 splits away to the north, was opened. By the end of 1960, from US 71 north of Atlantic to US 6 near Dexter, from I-35 to US 6 west of Newton, and from Iowa 38 near the Cedar River to US 61 in Davenport had opened to traffic. In eastern Iowa, new sections of road were opened in series. 1962 saw the eastern section extended 20 miles west to Iowa City and the central section was extended east to Grinnell. Iowa City's section of interstate was completed on November 15, 1963. A section, the longest section to be opened at one time, connected the two sections in October 1964. The easternmost section of I-80, from US 61 to US 67 at the Mississippi River, opened a month later. This gave travelers nearly of uninterrupted freeway driving. Construction then moved to the western half of the state. A new section from US 71 west to US 59 north of Avoca opened in December 1965. A year later, the Interstate was 90 percent completed when two stretches, a stretch from US 59 to I-29, which included of I-80N and the missing section between the western section and Des Moines, each opened to traffic. Sections of I-80 in the Council Bluffs area did not open for another couple years. A short section between Madison Avenue and US 6 opened in 1968. The Interstate was completed from the eastern junction with I-29 to I-80N in late December 1969. On both sides of the state, the respective river crossings opened to traffic nearly two years later than the connecting highways. Near LeClaire, the Fred Schwengel Memorial Bridge over the Mississippi River opened in 1966 after the highway had been completed to US 67, which runs at the foot of the bridge, in 1964. The center span of the Mississippi River bridge was installed on June 29, 1966. The , piece was floated into place by barge. In Council Bluffs, the Missouri River crossing opened on December 15, 1972, while the approach to the bridge opened