In order to provide a safe connection from Oak Ridge Park to the trails at McDonald Woods Forest Preserve, the Lindenhurst Park District installed a bicycle and pedestrian underpass beneath Grass Lake Road. The project was a joint effort between the Lindenhurst Park District, Lake County Forest Preserve District, Village of Lindenhurst, and Lake Villa Township.

This $2.7 million project received Safe Routes to School and Congestion Mitigation and Air Quality grant funding for construction. As a result, a formal Phase I Engineering Study and Phase II Engineering Design were required per funding guidelines. Gewalt Hamilton Associates (GHA) led the Phase I efforts and prepared the Phase II design documents. Specific services included topographic and boundary surveying, preparation of plat of highways, permitting, coordination with regulatory agencies, preliminary and final engineering. GHA also provided drainage and hydraulic analysis, and preparation of a wetland delineation report. Permits were required from the Lake County Department of Transportation, the Illinois Department of Transportation, the Lake County Stormwater Management Commission, and the US Army Corps of Engineers.

Once approved, GHA provided Phase III Construction Engineering for the underpass and associated improvements. Construction phase services included full-time resident engineering and documentation, National Pollutant Discharge Elimination System monitoring in compliance with the ILR10 permit, and Designated Erosion Control Inspection services as required by the County.

Construction of the Grass Lake Road Underpass was completed on schedule in September of 2015. and provides hundreds of pedestrians and bicyclists access to local parks, Forest Preserve District properties – including the county-wide Millennium Trail system – and residential neighborhoods.