What will this project do?
The goal of the project is to improve the capacity, safety, and reliability of I-70 between Wentzville Parkway and I-64. The project will shift I-70 to the southeast, add lanes and replace the existing Norfolk Southern Railroad (NSRR) bridge over I-70. The existing bridges over Route Z/Church Street will also be widened as part of this project.
Why is this project needed?
This section of I-70 sees a lot of congestion due to high traffic volume in the area, as well as the alignment of the interstate beneath the railroad bridge. This portion of I-70 was originally constructed in the 1950s and is no longer capable of reliably handling the traffic volumes in the area. However, the existing railroad bridge over the interstate limits the options for widening and improving the road. Currently, I-70 between Wentzville Parkway and Route Z is two lanes with narrow inside and outside shoulders as it crosses beneath the railroad. The area just to the east of this stretch of I-70 is the I-70/I-64 interchanges, which has been identified as one of the greatest bottlenecks in the St. Louis region. The 20-mile section of I-70 from the I-70/I-64 interchange to Warrenton experienced an estimated user delay cost of $12.7 million in 2016. Reconstructing and expanding even a portion of this stretch of I-70 will improve the safety, reliability, and capacity of the interstate for both freight and passenger vehicles.
What exactly is being done?
MoDOT investigated three alternatives to improve traffic congestion in this area. All three alternatives included plans to improve safety and decrease congestion by revising the I-70 alignment, widening a portion of the interstate, and addressing the railroad bridge. Roadway, traffic, and railroad impacts associated with each option were reviewed and studied, along with the development of estimated construction costs.
The first proposed alternative realigns I-70 to the southwest and raises the grade to cross over the railroad. This is what is shown in the previous Improve I-70 study completed in 2006:
The second alternative, which is the preferred alternative, widens and slightly realigns I-70 to the southwest including constructing a new Norfolk Southern Railroad Bridge crossing over I-70.
The third alternative relocates eastbound I-70 to the southwest and adjusts the elevation to cross over the railroad, while widening and leaving westbound I-70 in its current location underneath the railroad.
Why is Alternative 2 the Preferred Alternative?
Alternative 2 has fewer impacts on adjacent properties. I-70 crossing over NSRR as detailed in Alternatives 1 & 3 would require a significant rise in grade on I-70. This would cause trucks to slow down as they climbed the grade. Alternative 2 is also the least costly of the alternatives analyzed and represents the best value to the public.
How much will this project cost?
The estimated project cost of the preferred alternative is $38.5 million.
Is there funding for the project?
The project is on the region’s Long-Range Transportation Plan but is not yet funded. It is a top unfunded need in the St. Louis area. Until it is funded, MoDOT continues to work on the design, environmental clearances, and coordination with NSRR to ensure this project will be completed once funding becomes available.