December 14, 1961: First segment, between Cottage Grove Avenue and Keo(sauqua) Way,
November 9, 1963: Segment between Keo Way and East 6th Street opened
December 13, 1966: Segments between 31st Street and Cottage Grove Avenue, and
between East 6th Street and University Avenue (IA 163) opened
December 6, 1967: Segment between 63rd and 31st Streets, and between University
Avenue and the northeast I-35/80 interchange, opened
October 30, 1968: Last segment, between the southwest I-35/80 interchange
and 63rd Street, opened
(Source: I-235: Unearthing the Past, a PDF document from the Iowa DOT.)
While I-35 and I-80 bypass Des Moines to the north and west, I-235 runs right through the heart of the city. Those traveling eastbound on I-80 can keep going straight if they miss their turn in West Des Moines because 14 miles later, I-235 intersects with I-80 again. (The same situation exists on I-35 southbound near Des Moines — go straight, and you'll reach
I-235 is named the MacVicar Freeway, in honor of two former mayors of Des Moines: John MacVicar Sr. (1896-1900, 1916-1918, 1928) and John MacVicar Jr. (1942-1948); the latter also served as the city's street commissioner in the 1930s. The name was adapted by the Des Moines city council in October 1963. (Source: Des Moines Register article, "Super Road Slices Through City," November 24, 1993)
Reconstruction of I-235, Iowa's most heavily used Interstate, began in March 2002 and was completed by the end of 2007. The $423 million project included bridge widening and replacement, installation of noise walls, reconstructing several interchanges, and repaving the road. The new road also eliminated all left-lane exits and entrances, and is six lanes wide throughout the route with an eight-lane stretch between IA 28 and downtown. (Before reconstruction began, only the stretch between the 8th Street exit in West Des Moines and the University Avenue exit was six lanes wide. The segment between the I-35/80 "West Mixmaster" and 8th Street opened to six lanes of traffic in December 2004.) A dedication ceremony was held at the Iowa Events Center's Hy-Vee Hall on October 18, 2007. Photos of I-235 can be found on the I-235 page of the Photo Gallery.
Despite the reconstruction, congestion still occurred during rush hours on the westbound segment of I-235 between 63rd and 73rd Streets in Windsor Heights, where the highway narrowed from four lanes in each direction to three. Because of this, the DOT added an extra auxiliary lane along of that stretch of I-235 in 2013.
The first four exits of I-235, through West Des Moines and Windsor Heights, were numbered in 1969 as part of a Highway Commission experiment with Interstate exit numbering. (I-80 received exit numbers in 1971, but they were sequentially numbered. Iowa adopted mileage-based exit numbering for all Interstates in 1977, but the unnumbered exits on I-235 were ignored for some reason.) The remaining exits were numbered when new signs were put up during the reconstruction project.
I-235 was the first highway to have tenth-mile markers in the median, which were installed in June 1997 in response to the growing number of cellular phone users reporting emergencies on the highway. (They were replaced during reconstruction.) Similar markers have been placed along I-35/80 and US 65/IA 5 in the Des Moines area, I-80 and I-29 in Council Bluffs, I-29 in Sioux City, and I-74 in Davenport and Bettendorf.