Des Moines Bypass

The bypass begins at directional T interchange with I-35 on the southwestern side of West Des Moines. It heads east, between the Raccoon River to the north and the Polk–Warren county line to the south. The first interchange, S. 35th Street, provides access to Walnut Woods State Park, which resides on the southern bank of the Raccoon River. At the Southwest Connector, which will eventually provide a connection between I-35 and downtown Des Moines, the bypass dips to the southeast. For the next , the bypass runs within north of and parallel to the Polk–Warren county line until it dips into Warren County east of Norwalk. A partial cloverleaf interchange with Iowa 28 marks the halfway point of that stretch. Just south of the Polk–Warren county line, US 65 (US 65) and US 69 intersect the bypass at a full cloverleaf interchange. Here, US 69 is the north–south through road, while US 65 merges onto the bypass from the south and off from the north. This last interchange in Warren County is by far the busiest of the three as over 18,000 vehicles use US 65 / US 69 daily to commute between Des Moines and Indianola. North of the Iowa 163 interchange, the bypass curves to the north-northwest. It skirts the western edge of Altoona, where it intersects 8th Street SW and US 6, which runs along Hubbell Avenue, at a combined interchange. 8th Street and Hubbell Avenue are in such close proximity here that a half diamond interchange was constructed for each street and the two interchanges were connected by a short access road in each direction. The bypass continues to the north-northwest for . It ends at a trumpet interchange with I-80. ==History==

The bypass was planned as two four-lane highways that would divert traffic around the south and east of Des Moines. Iowa 500 was planned to extend from the vicinity of Avon in southern Polk County northward through Pleasant Hill and to terminate at I-80 near Altoona. Iowa 592 was designed as a much longer highway. It would extend from I-35 near West Des Moines to Iowa 92 south of Pleasantville. Iowa 500 In the 1970s, the Iowa Department of Transportation (Iowa DOT) began a study on the location and environmental impact of a new highway around the east side of Des Moines. The "500 facility" (Iowa 500), as it was referred to in the study, was loosely defined as extending from the intersection of Iowa 5 and Iowa 46 near Avon to I-80 near Altoona. The study produced five alternatives; four potential routes and a plan that did not result in any new road construction and discussed the environmental impact of each. The no build option was almost immediately rejected. Since Iowa 46 passed through an industrial area on Des Moines's east side, traffic was predominantly heavy trucks. The study projected traffic to increase to a point where Iowa 46 would be functionally obsolete. The next option was to expand existing city streets where possible. It would have started from the intersection of Iowa 5 and Iowa 46 near Avon and head north along Iowa 46. At the Des Moines River, it would curve off to the northeast to the eastern side of Pleasant Hill. It would then follow East 56th Street north Altoona, where it would curve slightly to the northwest to end at Hubbell Avenue, which carried US 65 towards Marshalltown. This route was rejected because it quickly would have become functionally obsolete as well. The "Inner Freeway West" route would start at Iowa 5 west of Avon. It would head north, roughly following Four Mile Creek to University Avenue (Iowa 163). North of University, the freeway would run to parallel East 42nd Street and end at I-80 near Berwick. This route was rejected because it would have split eastern Des Moines into two halves and would have required many homes in the area to be demolished. The "Outer Freeway" was the longest of the potential routes. It would start near the Iowa 5 / Iowa 46 intersection and head to the northeast. After crossing the Des Moines River, the freeway would curve to the east and then again to the north. The freeway would then head due north along the east side of Altoona ending at I-80 east of the First Avenue interchange. All of the construction options largely agreed that south of the intersection with Iowa 500, Iowa 592 would be an expansion of the two-lane Iowa 5 with bypasses around most of the towns along the route. The next option was to improve Army Post Road, which carried Iowa 5 through the south side of Des Moines. Army Post Road was an arrow-straight street from I-35 to Iowa 46, so upgrading it to four lanes would have been easy. However, it was already a four-lane street through Des Moines, so the additional traffic that would be added by the completion of Iowa 592 would have quickly rendered the street functionally obsolete. ==Future==

In 2012, City leaders in Des Moines and Carlisle suggested the bypass be redesignated as Interstate 335 (I-335) in order to give the entire route a less confusing name. The Iowa Department of Transportation said it would take over a year to determine if the design of the road would justify redesignating the highway. It never happened due to objections of slow moving farm equipment not having alternate route as slow vehicles aren't permitted on interstate highways. In May 2025, a proposal was revealed after years of it being shelved with potential designation of Interstate 435 (I-435). An alternate route for farm equipment must be identified as well. ==Exit list==