US-31 rebuilding - Grand Traverse & Benzie counties

MDOT gathered input from the community during the road safety audit (RSA) conducted in summer 2022. The stakeholders invited included emergency services, local government, public transit, and trail advocacy groups to discuss collaborative and cooperative aspects of the project to improve the safety for all users.

Based on input from that meeting, MDOT’s consultant designer for this project, RS Engineering, developed several project concepts that were presented at a public meeting in July 2023 in Interlochen. The concepts were displayed as part of the presentation at the meeting, and attendees were encouraged to provide comments. Those comments were documented and are available to review on the project website. MDOT is also gathering additional comments through an online form on the project website. A second public meeting was held in July 2024 to provide a project design and construction update, with the same methods available to make comments.

MDOT is planning to include wider paved shoulders with rumble strips throughout the entire corridor to provide more space for cyclists and pedestrians. Additionally, at the intersection of US-31 and J Maddy Parkway/South Long Lake Road, the existing crossings will be improved to include well-marked crosswalks at the roundabout, along with sidewalk added adjacent to the intersection. This sidewalk will extend existing sidewalk along J Maddy Parkway to the roundabout, then east to the Hudson Development and west to Kozy Court.

Design is scheduled to be complete in fall 2024 with construction occurring in 2025 and 2026. 

Traffic counts were taken after a Sept. 1, 2023, concert and analyzed with the proposed roundabout. The anticipated delay was 10 seconds for current traffic volumes and less than 20 seconds in 2045, after 20 years of traffic growth. The little opposing traffic would allow event traffic to essentially free-flow through the roundabout without police assistance.

A traffic growth rate 50 percent greater than the statewide average was used for this project to estimate traffic volumes in 2045. Additional contingencies were added to these future traffic volumes and analyzed, resulting in a maximum anticipated delay of approximately 20 seconds for the morning peak hour and 25 seconds for the evening peak.

The existing grades on both US-31 and E Duck Lake Road lead to sight distance concerns. Additionally, the low intersecting angle allows northbound US-31 right turns to occur at unsafe speeds and make left turns from E Duck Lake difficult. The addition of a dedicated right-turn lane on northbound US-31, realigned E Duck Lake Road, and grading improvements will improve the safety and traffic operations. Removing access was evaluated but the rerouted traffic could not be accommodated at Pine Tree Road. 

Due to the continuous flow of traffic through a roundabout, there is less vehicle platooning from what typically occurs at a traffic signal. Observations from other recently built roundabouts show that gaps in traffic away from roundabouts are shorter but more frequent, while traffic signals result in fewer but longer gaps. This difference leads to at least a similar, and likely improved, access to US-31 from side roads, which would reduce delay at intersections like Gonder, Bendon/Lake Ann, and Reynolds roads.

Benzie and Grand Traverse county roadways will be improved in summer 2025 to handle detoured US-31 traffic. These improvements will include thicker pavement and wider shoulders, the addition of turn lanes, and temporary traffic signals to accommodate the detoured traffic. Removing the poor soils at the Cedar Hedge and Tonawanda Creek bridges will require a detour of both northbound and southbound US-31 traffic during fall 2025. Signs will be included in advance of the detour stating that local and business access remains open.

The plan as it currently stands is that during the initial 2026 construction season, US-31 will be rebuilt first from Sullivan Road through the Interlochen Corners roundabout. Southbound US-31 traffic will be maintained on US-31 while northbound US-31 is detoured to local roadways. Construction on the north half of US-31 will occur first, followed by the south half.

During the latter 2026 construction season, US-31 will be rebuilt from the Interlochen Corners roundabout through Reynolds Road. Southbound US-31 traffic will remain on US-31 while northbound US-31 is detoured to local roadways. Construction on the south half of US-31 will occur first, followed by the north half. This plan may change as additional design details evolve and the contractor has had a chance to review the plan. 

Additional details regarding these detour routes can be found in the June 18, 2024, public meeting information on the project website.