Lake Saint Louis Boulevard / I-70 Interchange Roundabout

Lake St. Louis has experienced increasing traffic congestion and delays on the south side of the Lake St. Louis Boulevard interchange with Interstate 70.  Oates studied potential intersection improvements at the interchange, specifically roundabout configurations, for two existing closely spaced signalized intersections on the south side of I-70.

Projected traffic growth was developed by analyzing existing and projected land use in and around the study area, and the potential impacts to the intersection and the proposed layouts.  In order to allow for additional potential development, the study used a more aggressive annual growth rate for certain legs.  A conceptual layout was developed and a detailed operational analysis for each alternate was completed with the roundabout-specific analysis program Rodel. The two signalized intersections north of I-70 were analyzed using Synchro to determine if the operation of these intersections would have an impact on either proposed alternate or if the anticipated traffic growth would affect their operation and negatively impact the proposed roundabout.

A report was prepared that identified conflicts, constraints, impacts (utility and right of way), and costs.  Oates established design criteria, analyzed traffic data, developed conceptual geometry, provided analysis of traffic operations for each alternate, and provided estimates of cost for each alternate.

Oates Associates is currently designing improvements.