MoDOT selects Millstone Weber for the Interstate 70

Cave Springs to Fairgrounds Design-Build Project

ST. CHARLES COUNTY – The Missouri Highways and Transportation Commission (MHTC) announced the selection of the Interstate 70 Cave Springs to Fairgrounds (CSFG) Design-Build Project to Millstone Weber LLC during its monthly meeting in Jefferson City today.

Millstone Weber LLC teamed with Parsons Transportation Group Inc. in their I-70 CSFG project proposal addressing improvements to connectivity, safety and congestion problems for this section of I-70 in St. Charles County.

Project details include:

  • maintaining the existing two-way outer road system between Cave Springs and Fairgrounds
  • building a new two-way north outer road between Zumbehl and Route 94/First Capitol Drive
  • building a new one-way north outer road from Fairgrounds to Route 94
  • constructing new interchanges at Cave Springs Road and Zumbehl Road in a Single-Point Urban Interchange (SPUI) design to address safety and congestion
  • adding a 10-foot-wide shared use path for pedestrians on both new interchanges

This project allows for potential future expansion of Interstate 70, which currently remains unfunded.

This Design-Build project is a partnership with St. Charles County, who has contributed $10 million of the $62 million cost of the reconstruction.

“One of the major concerns among residents and businesses were the outer road system,” said Stacey Smith, MoDOT Project Director. “Millstone Weber’s proposals maintains the existing two-way outer road system with estimated reductions in crashes and delays with the construction of new interchanges at Cave Springs and Zumbehl.”

This project is a regional priority for MoDOT and St. Charles County due to the high crash rate, including 3,000 crashes in the past five years. The current roadway design and inefficient traffic flow have restricted connectivity for over a decade. The congestion at the interchanges often causes traffic to back down the off-ramps to I-70 during rush hours. Better connectivity will make access to local businesses and homes easier.

This section of I-70 was built in the 1950s and 1960s, making it one of the oldest sections of interstate in the country and one of the busiest in Missouri.

For more information, visit for project updates.





Districts Involved
St. Louis