MoDOT and St. Charles County are working together on improving Route N from Route Z on the west to I-64 interchange on the east. This effort began in late 2023 with preliminary design completion anticipated by December 2025.

This work is the next step towards designing the improvements identified in the Planning and Environmental Linkages (PEL) Study completed in 2022.

As the next step, the project team will confirm assumptions made in the PEL Study and further detail corridor improvements in order to identify the future roadway footprint, impacts and funding needs. 

Improvement alternatives will be evaluated during conceptual design, with a resulting single concept that will be further developed through preliminary design by October 2025.

The continued growth in western St. Charles County has caused significant increases in both local and regional traffic along Route N west of I-64. The purpose of the Route N Expansion is to improve access and safety, reduce congestion, improve pedestrian connectivity, and plan for future growth.
Proposed improvements include:

• Additional lanes
• Improved Traffic flow
• Safer intersections
• Upgraded corridor