By JUSTIN WOLF

The Jefferson County I-55 Corridor Upgrades are a $246 million, three-year, design-build project.

The work consists of adding a third lane to I-55 for eight miles starting just north of the Route Z interchange in Pevely, Mo. (where the three-lane section currently ends) to the U.S. Route 67 interchange in Festus, Mo. The KCI team – comprised of KCI Construction Company, Bartlett & West and Wilson & Company – was selected as the contractor for the project in July 2023. Construction started in early December 2023. The I-55 project also includes improvements to three major interchanges at Route Z, at McNutt and at U.S. Route 67. Minor work will also take place at the Route A interchange.

As of February, 90 percent of the design has been completed, along with more than 30 percent of construction, including three miles of new concrete lanes and shoulder in the median, four new bridges and one of two new roundabouts at the I-55/Route 67 interchange.

This month will see a major traffic switch moving the southbound I-55 traffic onto the newly constructed median pavement from north of Central Avenue to south of the I-55/Route 67 interchange. The traffic switch allows for demolition of the existing southbound I-55 bridges over Central Ave., Third St. and Route 67 and existing pavement and for new construction to begin.

In addition to the traffic switch, the southbound Route 67 loop ramp to southbound I-55 will also be closed for six months while the southbound I-55 bridge over Route 67 is demolished and replaced. Traffic will be detoured on southbound U.S. Route 61 to the I-55 interchange (Exit 170) where drivers will be able to continue onto southbound I-55.

More information on the Jefferson County I-55 Corridor Upgrades project is online at  www.modot.org/projects/i-55-upgrades-jefferson. Drone footage of the construction progress is available on MoDOT St. Louis’ Flickr page here.

Justin Wolf is the I-55 project director for the Missouri Dept. of Transportation’s St. Louis District.