UPDATE on CLOSURE of Route O Warren County to Through Traffic

Due to a deteriorating road surface, Route O in Warren County, between Route M south to Missouri Route 47 at Marthasville has been closed to through traffic until further notice.  The area south of Polston has been reopened to local traffic.  In addition, the speed limit has been reduced to 35 mph. 

Over the last few months, Warren County Route O has been seeing an increase in truck traffic. This traffic, along with wet conditions and warmer temperatures, has caused significant roadway deterioration. Local residents are encouraged to pay attention to all posted signs, including the reduction in speed limit,  and to drive for road conditions.  In addition, motorcycles are advised to avoid travel on Warren County Route O at this time.

“We ask that local residents pay attention to the signs posted and drive for road conditions,” said District Engineer Paula Gough.

Crews will continue to make repairs, but motorists should expect the restriction to local traffic only and reduction in speed limit to remain.

To stay up-to-date on traffic impacts and other projects, we encourage you to sign-up for text and email notifications at You can also contact MoDOT by calling our customer service number at 1-888 ASK MODOT (275-3363).