MoDOT outlines major I‑70 rebuild, interchange work and local impacts near O'Fallon

Andy, a Missouri Department of Transportation area engineer, told the Public Works Advisory Committee on July 16 that the I‑70 program is a statewide push to provide six lanes across the state and that the Saint Louis District has folded many corridor projects together to improve efficiency.

The presentation emphasized scale and permanence: Andy said the combined Warrenton-to‑Highway K work amounts to roughly $600,000,000 for the district and includes multiple bridge replacements and full pavement rebuilds rather than overlays. "Everything you see on the screen, ultimately, it all plays well together," he said, and described the interchange package as one of the largest in MoDOT history.

Why it matters: the program changes lane and shoulder configurations, widens merge areas and aims to reduce long‑term maintenance. Andy described three 12‑foot lanes in each direction with 6‑foot shoulders and noted that new concrete placed will be diamond‑ground for a smoother, quieter surface.

Local schedule and staging: Andy said the section on I‑64 is expected to open segments by the end of the year, while the overall program is scheduled through 2028 with critical interchange elements in 2027–28. To limit traffic disruption, MoDOT paused standalone work on the Wentzville Curve so it could be blended into the larger plan. He also outlined staging to maintain at least two lanes during peak periods and to use temporary structures where needed.

Rail bridge and traffic impacts: For the railroad overpass near the interchange, MoDOT negotiated a temporary "shoe‑fly" alignment with Norfolk Southern so rail traffic can be moved to a temporary structure while the new, longer bridge is built. Andy said the approach is a "leapfrog" sequence that will allow construction of new eastbound lanes while preserving traffic flow during the work.

Local coordination: Committee members raised questions about whether Route 364 would be extended to I‑70 (Andy said no) and where roundabouts will be used (he said roundabouts are planned at some interchanges but not for the high‑speed 61/70 interchange). On a local bridge replacement at Technology Drive/Bridal Road, Andy said contractors are planning a full closure in early August because of vertical differential constraints and that MoDOT and the city are coordinating detours.

What comes next: Andy agreed to share the contractor's fly‑through video and additional materials with committee staff for public distribution. The committee thanked MoDOT for the presentation and noted continuing interest in staging, local traffic effects and timing.