U.S. Rte. 61 Roadway Elevation Project: Innovative Approach Keeps Traffic Humming During Work

By CHRISTOPHER KNAPP

Missouri’s transportation agency has completed a critical roadway elevation project to guard against future catastrophic flooding along an instrumental thoroughfare directly along the Missouri-Iowa border.

In 2024, the Missouri Dept. of Transportation began construction on a project to elevate a 1.3‑mile segment of U.S. Rte. 61 in Clark County, near Alexandria, Mo. Located between the region’s levee system and the confluence of the Mississippi and Des Moines rivers, this stretch of roadway serves as a vital link connecting Missouri with Iowa and Illinois.

For Missouri residents, Route 61 is more than a commuter corridor; it provides essential access to businesses in Alexandria and emergency medical services in Keokuk, Iowa. Seasonal flooding has repeatedly forced lengthy closures of this major route, creating a 41‑mile detour for travelers and first responders. These disruptions have long posed safety challenges, economic impacts and strains on regional mobility.

To address these concerns, this project raised the roadway elevation by approximately 2.5 feet between the existing levee and the Des Moines River bridge. While the elevation increase was designed to dramatically reduce flood‑related closures, traditional construction methods of removing pavement, placing earth fill, rebuilding the aggregate base and laying new asphalt would have required a full 90‑day closure of the corridor. Such a long disruption would have created significant hardships for residents, businesses and emergency services.

During the planning process, MoDOT identified an innovative construction strategy that preserved community access throughout the project with minimal traffic impacts. Instead of demolishing the existing pavement, the contractor applied a series of four‑inch asphalt base lifts, gradually building the roadway to its new elevation. While a temporary closure lasting only a few days was needed to install drainage components under the roadway, this stair‑step method allowed traffic to remain on the corridor with one‑lane operations and a pilot car, much like a typical asphalt overlay.

Not only has this approach demonstrated practical advantages in cost, efficiency and mobility, but it also earned top recognition in the Projects category at MoDOT’s annual Innovations Showcase.

With the ability to maintain emergency access, avoid a lengthy detour and minimize business impacts, this method delivered meaningful benefits for local residents and the broader region, illustrating how innovative thinking can strengthen infrastructure while supporting the communities that rely on it.

Christopher Knapp, P.E., is project manager of the Missouri Dept. of Transportation’s Northeast District.