Prairie Research Institute


PRI contributes crucial expertise to transportation infrastructure projects throughout Illinois.

Work by PRI scientists enables both the Illinois Department of Transportation (IDOT) and Illinois State Toll Highway Authority (Tollway) to comply with the National Environmental Policy Act, the Clean Water Act, the National Historic Preservation Act, and Endangered Species Act. PRI’s work also allows these agencies to avoid the delays and cost overruns that could arise if previously unidentified environmental hazards, endangered or protected species, or cultural artifacts were encountered during infrastructure projects.

Aggregate Resources

The Illinois aggregate and construction industries also rely on PRI as the sole objective source for information about the location and quality of the sand, gravel, and crushed stone resources that are essential for transportation infrastructure projects.

Hazard Assessments

PRI geologists conduct environmental assessments that evaluate potential hazards and risks that may affect plans for future infrastructure uses of the land. Identifying these issues in advance helps IDOT avoid costly project delays. PRI has completed more than 5,000 of these environmental assessments over the past 30 years, and highway projects alone have assessed over 13,000 miles of Illinois roads.

Water Quality and Environmental Impact

For decades, PRI scientists have evaluated wetlands, monitored water quality, and surveyed the plants and animals, including threatened and endangered species, impacted by IDOT and Tollway projects. The data provided by these efforts helps the agencies plan and assess mitigation and restoration efforts, certify credits for compensating for wetland losses, gauge the effectiveness of roadway runoff treatments, and develop conservation and management strategies.

Cultural Resources

Archaeologists assess how improvements and expansion of transportation infrastructure may impact archaeological resources and our cultural heritage.

For example, the construction of the Stan Musial Veterans’ Memorial Bridge required what was then the largest archaeological excavation in the nation to mitigate the adverse impact on the prehistoric East St. Louis Mound Complex. Excavation of 34 acres identified hundreds of homes and public buildings and generated insights about what was once North America’s largest urban center.

Highway Flooding

Without IDOT’s pumping stations, the natural water table in parts of East St. Louis would flood interstate highways in several locations. For more than 20 years, PRI staff have helped IDOT maintain the pumps and understand the hydrogeology of the area.


PRI provides statewide data on the location of cover-collapse sinkholes, which pose a serious hazard for the construction of buildings, roads, and other infrastructure. Sinkholes can also make groundwater more vulnerable to contamination. This is of particular importance where sinkholes are prevalent, in the Illinois “sinkhole plain” (principally within Monroe, Randolph, and St. Clair counties).