US-31 rebuilding - Grand Traverse and 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, Clark Dietz, 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. We anticipate another public meeting before the major construction begins in the spring of 2026.

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 east of J Maddy Parkway to the roundabout along with adding sidewalk to the west of J Maddy Parkway to 1st Street. From the roundabout, sidewalk will be constructed east to the Hudson Development and west to Kozy Court.

Construction will occur from Spring 2025 through Fall 2026.

Tentative schedule for construction:

• Spring - Summer 2025: Tree clearing and detour route improvements.
• Fall 2025: Unsuitable soil excavation and replacement at Tonawanda Creek and Cedar Hedge Creek bridges. Detours required.
• Spring - Summer 2026: US-31 rebuilding, Sullivan Road to west of J. Maddy Parkway/S. Long Lake Road, including roundabout construction. Detours required.
• Summer - Fall 2026: US-31 rebuilding, west of J. Maddy Parkway/S. Long Lake Road to Reynolds Road. Detours required.

Once a contractor is awarded for the 2026 construction a more detailed construction schedule will be available.

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.

During the initial 2026 construction season, the project will be broken into two sections: the eastern section from Sullivan Rd through the Interlochen Corners intersection (including roundabout construction) and the western section from Interlochen Corners to Reynolds Rd. 

We anticipate the eastern section to be rebuilt first. During construction of the eastern section, 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 is anticipated to occur first and then the south half.

Once the eastern section is completed, construction will begin on the western section. During construction of the western section, southbound US-31 traffic will again remain on US-31 while northbound US-31 is detoured to local roadways. Construction on the south half of US-31 is anticipated to occur first and then the north half. This plan may change if  the construction contractor proposes an alternative plan that is approved by MDOT.

Additional details regarding these detour routes can be found on the project website. 

As with any project that involves a detour on local roadways not under MDOT jurisdiction, MDOT selected the official detour route in cooperation and consultation with the Benzie and Grand Traverse County road commissions. Detour routes are selected based primarily on their suitability to handle state highway traffic, including commercial traffic. In this case, MDOT made improvements to the local roads to be used for the detour, paving sections and adding temporary traffic signals and signs, to ensure they could accommodate this shift in traffic.

The first week or two of any detour is always disruptive, as drivers adapt to new traffic patterns and the effect on their travel schedules. These issues generally improve after this time as drivers get used to the new traffic controls and adjust their schedules. MDOT does monitor detour routes and can make adjustments as needed, sometimes changing temporary traffic controls to help improve traffic flow and improve adherence to new signs and signals. Although we cannot ensure that drivers follow the posted signs and signals, we do work with law enforcement agencies to help encourage compliance when necessary.

MDOT does everything it can to encourage drivers – particularly those who are intending to just bypass the construction zone closure – to use the official detour route, including making upgrades to the pavement and traffic controls to make it the most efficient route. MDOT, in addition to directional signs placed along the route, has issued news releases, posted detour route maps on the project website, and participated in media interviews encouraging the use of the official detour route. However, depending on their destination, some drivers may find that another public roadway will be more convenient and direct, and they are legally able to do so. This does not negate those drivers’ need to follow posted speed limits and obey all signs and signals on their chosen route, but MDOT cannot prohibit them from using other public roadways.

What MDOT can do, and has done, is reach out to our partners at the road commission to discuss what other signs or measures could be employed to help remind drivers of their responsibilities on these other routes. We have also discussed this issue with law enforcement, who can determine whether additional patrols along these routes are appropriate to slow speeds or ticket drivers who disregard the posted speed limits. Additionally, we have deployed two speed-reporting trailers and are seeking additional enforcement in the area from our partners at the Michigan State Police (MSP).

MDOT is able to install new signs and make pavement improvements on official detour routes only because those local roads become state trunkline when they are designated for a detour. Other local roads remain under the jurisdiction of the county road commission or local municipality. We certainly can consult with the local road owners about any additional signs or improvements, but they make those determinations.