Minnesota's I-35 Planning Study

Federal Highway Administration2022PDFTech ReportKersavage, KristinVHB/Vanasse Hangen Brustlin, Inc.United States. Federal Highway Administration. Office of SafetyRoche, JerryPascual, Sarah WeissmanUnited States. Federal Highway Administration. Office of SafetyUnited StatesMinnesotaInterchangesInterstate highwaysTraffic safetyRehabilitation (Maintenance)FreewaysSafetyISATeHighway Safety ManualFHWA-SA-21-077DTFH61-16-D-00052Roche, JerryCase StudyThis case study describes the Minnesota Department of Transportation\u2019s (MnDOT's) use of the Enhanced Interchange Safety Analysis Tool (ISATe) as a part of a planning study for an approximately 7-mile segment of Interstate 35 (I-35) in Carlton County. I-35 carries commuter and recreational traffic, and it is a main freight corridor for the area. Most of the bridges in the study area were 45 to 55 years old, and many of the bridges and pavement sections along the corridor were reaching the end of their service life and would require rehabilitation or replacement. This study identified safety, operational, and mobility needs along the corridor and developed alternatives which were then coordinated with upcoming infrastructure replacement projects. The I-35 planning study is an example of incorporating quantitative safety analysis as part of a comprehensive review process. MnDOT's work to obtain stakeholder feedback and analyze existing safety conditions allowed the project team to establish safety as a project need. Additional evaluation of specific needs led MnDOT to develop a suite of alternatives that balanced environmental sensitivity with access and safety. ISATe provided the technical capacity to assess the study area\u2019s baseline conditions based on existing geometrics and traffic, and estimate predicted crashes based on forecast conditions. The benefit-cost analysis provided further confidence that MnDOT's alternatives will be cost effective and will provide a high level of benefit to users of the I-35 corridor.137