Clark Dietz is honored to serve as the lead engineer for the US-31 rebuilding project, a transformative $32.5 million initiative led by the Michigan Department of Transportation (MDOT). Spanning 7.8 miles through Benzie and Grand Traverse Counties, this corridor is a lifeline for residents, tourists, businesses, schools, and visitors to popular destinations like Interlochen State Park and the Interlochen Center for the Arts.
US-31 Roundabout Design
From the very beginning, MDOT’s priority was clear: safety for all users. This stretch of US-31 had a documented history of crashes, including several serious injuries, especially at key intersections. The redesign incorporates center left-turn lanes, wider shoulders with rumble strips, and ADA-compliant sidewalks and crossings. At the critical South Long Lake Road/J. Maddy Parkway intersection, a two-lane roundabout will improve access and visibility while reducing crashes by an anticipated 55%, with a 78% drop in injury-related crashes.
More Than Engineering: A Comprehensive Approach to Community-Focused Design
Our role extended beyond engineering. As the lead engineering firm, Clark Dietz’s multidisciplinary team went beyond roadway design and included:
- Traffic analysis, capacity and geometric analysis, and safety improvements
- Drainage design
- Development of Maintenance of Traffic (MOT) and Transportation Management Plans (TMP)
- Mentorship in signing and pavement marking design
- Public engagement strategies and communication tools including collaborating on a GIS story map
In collaboration with Fishbeck, Gourdie-Fraser, and SME, we brought together expertise in surveying, hydraulics, geotechnical engineering, and environmental design, ensuring every element of the design aligned with the context of the corridor and needs of its users.
Honoring the Community: Listening, Learning, and Evolving
The voices of the community deeply influenced the design process. MDOT, committed to inclusive engagement, went door-to-door to notify and listen to residents and businesses throughout the corridor. Two public meetings created additional opportunities to listen and build trust, especially after years of mounting safety concerns.
First public meeting
The first public meeting was held at the Interlochen Public Library, a gathering space deeply rooted in the community. It was an emotional and intense event, highlighting just how personal this corridor is for so many residents. After hearing directly from attendees, MDOT and the design team made significant refinements, adjusting turn lanes, considering property impacts, and enhancing safety features.
Between meetings, the team updated materials to reflect evolving designs and comments, including:
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A GIS Story Map with crash data, context-sensitive renderings, and design comparisons
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Updated FAQs, handouts, and comment response summaries
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Before-and-after visuals of signal modernization vs. roundabout alternatives
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A transparent public-facing website with consistent updates
At the second public meeting, the tone had shifted. The community arrived with informed questions, and the larger room was staffed with MDOT specialists, from public engagement and real estate to regional planning and traffic operations, alongside Clark Dietz engineers. It was clear the community saw their fingerprints on the design.
Second public meeting
One resident remarked, “You can really see our comments were incorporated into the design!” This sentiment underscores our commitment to creating infrastructure that reflects the needs and pride of the community.
The third public meeting focused on construction logistics. MDOT and the project team walked attendees through the upcoming construction phasing and detour plans, helping residents, businesses, and commuters understand the timing, sequencing, and strategies to minimize disruption. This meeting emphasized transparency and preparation, continuing the strong rapport built with the community.
Engineering Quality of Life
Residents looking over the designs with Road Engineer, Alex Oosterhoff, PE
The redesigned corridor reflects the shared goals of safety, access, and quality of life. Whether it’s a child walking to school, a cyclist heading to work, or a family visiting the park, the new US-31 will better serve the people who live, work, and travel along it every day.
Right now in 2025, crews are upgrading the designated detour routes to ensure they can safely accommodate traffic during next year’s reconstruction. In 2026, full construction begins, including the new roundabouts and corridor-wide improvements that will reshape how people move through this region.
We’re grateful for the opportunity to work alongside MDOT and this incredible community, and we look forward to continued collaboration as the vision becomes reality.
➡️ For more details, visit the MDOT Project Page or explore the GIS Story Map.
Questions? Contact Clark Dietz Project Manager – Brian Smith, PE
