Route MM Safety & Maintenance Improvements

TREKK led the comprehensive study and design of targeted safety and maintenance enhancements along Route MM from Route 100 to Route T, transforming a corridor challenged by aging infrastructure and evolving traffic demands into a safer, more resilient roadway. Our team conducted a detailed inventory of existing safety features and culverts, paired with in-depth analysis of crash data, traffic volumes, and roadway geometrics to identify key risk factors and prioritize improvements. These findings informed a concept study report and clear, actionable design recommendations.

The resulting design delivers meaningful safety and operational upgrades, including new signage, pavement repair and replacement, guardrail improvements, and culvert replacements. Two large box culverts were extended, and an additional extension was designed to support stream mitigation. To address recurring sedimentation issues, TREKK performed HEC-RAS modeling to diagnose reduced culvert capacity. We implemented an innovative gabion basket system that strategically narrows the channel, increasing flow velocity during smaller storm events to reduce sediment buildup while maintaining full conveyance during large storms through a tiered configuration. The gabions are tiered to utilize the full culvert’s capacity during larger rain events.

To further enhance corridor safety, TREKK designed a roadway realignment beneath the Union Pacific Railroad and adjacent to Labadie Creek, improving sight distance and reducing driver risk in this constrained area. The realignment incorporates a 224-foot retaining wall, new guardrail, and drainage improvements, balancing safety, constructability and environmental considerations.

Our team supported these improvements with rigorous hydraulic and floodplain analysis using GeoHECRAS, completing a floodplain study, detailed hydraulic evaluations and a No-Rise Certification. TREKK also led utility coordination efforts, including Missouri One Call coordination, utility provider engagement, site verification and relocation planning to accommodate widening and drainage improvements. Relocates were necessary for the shoulder widening and proposed pipe culverts. TREKK assisted with markings in the field and coordinated with the utility companies to help ensure the relocations were successful.

TREKK delivered end-to-end services, including concept development, roadway and safety design, hydrologic and hydraulic analysis, utility coordination, and final plans, specifications, and estimates, providing a cohesive, data-driven solution that enhances long-term safety, performance, and resilience along the Route MM corridor.