Garden Kingdom

Garden Kingdom is a planned 74-acre development in Glen Carbon, Illinois that will include professional offices, sit down restaurants, student housing, residential lots and potentially a convenience store with gas pumps.  Access to the site will be via a new west approach at the existing signalized intersection of IL-157 and West Main Street.  A traffic study was conducted to identify the required entrance lane configuration and to assess potential impacts at the intersection of IL-157 and West Main Street.

The existing background traffic along IL-157 was determined by reviewing published traffic counts and providing manual traffic counts.  Projected development traffic was estimated using published rates in the ITE “Trip Generation Manual” and by observing traffic patterns from existing, similar development in the Glen Carbon area.  Once the proposed development traffic was determined, it was assigned to the existing transportation network and impacts to the surrounding network were evaluated.  The evaluation included reviewing turn-lane warrants, traffic signal warrants, truck turning movements, and reviewing entrance operations.  Based on the evaluations, countermeasures were suggested to mitigate negative effects to the existing roadway network.  The traffic impact study (TIS) was ultimately approved by the Illinois Department of Transportation and the Village of Glen Carbon and the suggested countermeasures, which included two turn lanes and traffic signal modifications, were added to the development construction plans.