I-75/M-32 Interchange Rebuilding Project

MDOT and its consultant considered three primary options for the interchange:

• A Diverging Diamond Interchange (DDI)
• A Single-Point Urban Interchange (SPUI)
• A modified and improved design of the current interchange

While initially considered as an option, MDOT ruled out the option of roundabouts for the interchange early on due to the capacity limitations of roundabouts.

In the quest to determine the interchange that will be part of Gaylord’s future, the Diverging Diamond Interchange (DDI) emerged as the frontrunner, backed by a wealth of supporting data:

• Traffic Operational Analysis:
  • Rigorous analysis reveals that the DDI outperforms other options, ensuring optimal traffic flow well into the future as volumes continue to increase.
• Enhanced Safety Features:
  • DDI's unique design reduces conflict points and turning movements, significantly improving safety for all road users.
• Reduced Signal Phases:
  • Efficiency is key — fewer signal phases are required with the DDI, streamlining traffic movements and minimizing delays.
• Pedestrian-Friendly Design:
  • Prioritizing safety, the DDI requires fewer pedestrian crossings, creating a more accessible environment for all roadway users.
• Local Public Support:
  • Your voice matters, and the DDI has garnered strong local public support. It reflects the preferences and needs of Gaylord’s community members.
• Flexibility for Future Changes:
  • The DDI stands out in its adaptability, providing the most flexibility to accommodate changes in future traffic patterns and development, ensuring a forward-looking solution.
• Optimal Left Turn Storage:
  • Addressing the conflicting needs of Dickerson Road and the northbound I-75 on-ramp, the DDI excels in providing the most left-turn storage, optimizing traffic management.
• Snow-Resilient Design:
  • Acknowledging our winter climate, the DDI is less reliant on pavement marking visibility, ensuring continued functionality even in snowy weather.
• Comprehensive User Experience:
  • Striving for inclusivity, the DDI offers a good level of service for all users, including cyclists and pedestrians, fostering a community-centric design.
• Cost-Effective Bridge Placement:
  • A strategic advantage of the DDI is its ability to allow for the placement of center bridge piers for the I-75 bridges above. This not only reduces costs significantly but also simplifies the construction process.

Overall, the DDI not only optimizes traffic operations and safety but also aligns with the community's preferences.

Examples of Diverging Diamond Interchanges in Michigan include:

• I-94/US-127/West Avenue in Jackson
• I-75/14 Mile and I-75/Big Beaver Road in Troy
• I-75/University Drive in Auburn Hills

The decision to not choose a Single Point Urban Interchange (SPUI) for this location was carefully considered throughout MDOT's study. While the SPUI was initially a strong candidate, several factors led to its exclusion.

In terms of traffic efficiency, the SPUI and the Diverging Diamond Interchange (DDI) were closely matched, with little discernible advantage or disadvantage for either. However, the SPUI introduced an additional signal phase compared to the DDI, impacting signal timing flexibility along the corridor.

Despite apparent community support for the SPUI, three significant drawbacks influenced the decision against it. First, there were conflicting needs for left-turn storage for Dickerson Road and the northbound I-75 Ramp. Additionally, the dependency on visible pavement markings in snowy regions posed a challenge. Last, the absence of options to place a center pier for the I-75 bridges resulted in very long bridge span lengths, affecting bridge costs.

While SPUIs perform well under heavy traffic loads, they can create perceived excessive wait times during off-peak traffic. Moreover, the expansive section of pavement required by SPUIs, coupled with limitations in aesthetic appeal, contributed to the decision.

In summary, the choice against a SPUI considered a comprehensive evaluation of traffic efficiency, community input, conflicting needs, environmental considerations, and aesthetic concerns.

The modified and improved design of the current interchange initially appeared as a favorable option for MDOT due to its perceived cost savings over alternatives like the Single Point Urban Interchange (SPUI) and Diverging Diamond Interchange (DDI). However, this option faced challenges, particularly concerning the Dickerson Road intersection.

The requirement for Dickerson Road to align directly across from the I-75 southbound off-ramp, creating a 4-legged intersection, posed a significant issue. This additional leg necessitated an extra signal phase at the intersection, leading to complications in traffic flow. As a result, traffic modeling showed increased delays and longer travel times due to traffic demands, especially in the design year (2045). Looking beyond current traffic volumes revealed significant weaknesses in the resiliency of this design.

Despite MDOT's obligation to investigate the design year (2045), the evaluation extended beyond to assess the model’s long-term resiliency. Ultimately, the modified design did not meet the project goals concerning traffic operations, and it became unsustainable. Additionally, when considering both project cost and benefits, the option with the lowest cost turned out to have the lowest overall project value, further influencing the design decision.

The biggest change to the Dickerson Road intersection is the fact that it will become a three-legged intersection, instead of four, with the relocation of the southbound I-75 off-ramp. This allows for reducing the number of signal phases which improves the overall traffic flow of the intersection.

 An additional right-turn lane is being added from eastbound M-32 to southbound Dickerson Road and continuing to the southbound I-75 on-ramp, which will reduce travel time for right-turn traffic and increase the efficiency for through-traffic on M-32.

Vehicles traveling north on Dickerson Road will see improvements to right turns onto M-32. In addition to shifting the southbound I-75 on-ramp to the east, away from Dickerson Road, the curb radius will be enhanced to accommodate large vehicles so they don't need to cross multiple lanes of M-32 to make the sharp turn and avoid running over the curb.

These measures collectively contribute to improving traffic flow through the Dickerson Road intersection.

The project will incorporate enhanced pedestrian and bicycle facilities, prioritizing the safety and accessibility of non-motorized users. A key focus is on creating continuous and inviting sidewalks along the north side of M-32, meeting ADA standards for accessibility. Additionally, the shared-use path on the south side, extending from Dickerson Road, will be continued within the project limits. To further enhance accessibility, the south side will feature more open and inviting ADA-compliant facilities. MDOT is committed to ongoing planning efforts aimed at maximizing pedestrian and bicycle access throughout these project limits.

Various possibilities and alternatives will be presented to the City of Gaylord for consideration. While aesthetics aren't the primary factor in selecting a Diverging Diamond Interchange (DDI), it is acknowledged as a visually pleasing option with potential for aesthetic enhancements such as decorative lighting, tree plantings, decorative bridge treatments, gateway features, landscaping, and more. Importantly, the City of Gaylord would bear the responsibility for any associated costs for aesthetic improvements. MDOT is eager to collaborate with the City of Gaylord on this matter and looks forward to discussing the potential aesthetic improvements while ensuring cost considerations are addressed.

Traffic counts were collected with both temporary and permanent traffic recorders. A permanent traffic recorder on I-75 was used to count I-75 traffic. Traffic counts and turning movements on M-32 were collected with temporary traffic recording devices at the following intersections:

• Murner Road
• Meecher Road/Edelweiss Village Parkway
• Ted Drive
• Dickerson Road/Southbound I-75 off-ramp
• Northbound I-75 off ramp and on ramp
• West Street
• Ohio Avenue
• Wisconsin Avenue
• I-75 Business Loop (Otsego Avenue)
• Center Avenue (Old 27)

Traffic counts for both I-75 and M-32 were collected from Thursday August 4, 2022, to Sunday August 7, 2022. Additional traffic counts were collected in December of 2022 to obtain counts during the school year.

MDOT predicts traffic increases based on the historical growth rate of traffic at the project location. An annual growth rate of 0.5 percent is being utilized for this location. This number is thought to be conservative and ensures the success of this project beyond the 2045 design year.  The analysis considers the existing year (2022) and the future year (2045). The existing year is the year in which the traffic data was collected.

At this time, we are expecting that construction could begin as early as the spring of 2026 and be completed as late as the fall of 2027.  A more definitive construction schedule will be established as the plan development process progresses.

At this time, we expect to maintain one lane of M-32 traffic in each direction at all times, though M-32 will likely need to be closed and detoured at times when the I-75 bridges are demolished, and when the new bridge beams are installed. We also expect to keep at least one lane of I-75 open in each direction, though freeway traffic may be detoured at times using the on- and off-ramps. As with the construction schedule, a plan to maintain traffic will be established as the plan development process progresses.

Because the M-32 corridor is as much of a destination as it is a roadway to other places, it’s doubtful that another crossing of I-75 in the Gaylord vicinity would result in significant traffic diversion. In other words, drivers are on M-32 in Gaylord because they are coming for something Gaylord has to offer. Another overpass would likely not see significant traffic, though it might be more convenient for a small number of drivers. 

According to MDOT’s most recent traffic volume counts (2022), M-32 from I-75 to South Otsego Avenue had an average of 25,036 vehicles daily, dropping to 10,159 from South Otsego Avenue to the eastern city limits, and 3,649 east of the eastern city limits. M-32 west of I-75 to Murner Road had average daily traffic of 20,692vehicles, dropping to 11,687 from Murner to Hayes Tower Road, and 6,452 vehicles west of Hayes Tower Road. That’s evidence that the vast majority of traffic on M-32 in Gaylord has an origin or destination on that corridor, rather than traffic passing from one end of the city to the other.

As for a full interchange at McCoy Road, again, it’s doubtful this would result in significant traffic diversion. Putting new entry and exit ramps on I-75 at McCoy would be very close to the Exit 282 ramps, and extremely close to, if not touching, the Exit 279 ramps.

In any case, additional overpasses or an interchange at McCoy would need to follow a separate planning process and identification of funding. This current planning process is being driven by the need to replace the I-75 bridges over M-32, a need that isn’t addressed with other interchanges or overpasses.

Over the years, The Michigan Department of Transportation (MDOT) has received inquiries about a potential interchange on I-75 at McCoy Road in the city of Gaylord. MDOT’s proposed I-75/M-32 interchange (Exit 282) reconstruction project has elevated these inquiries again. This I-75/M-32 interchange project is rooted in the need to replace the existing I-75 bridges over M-32 due to their poor condition. This also creates an opportunity for MDOT to evaluate and incorporate geometric, operational, and safety improvements at this interchange.

Federal Highway Administration (FHWA) requirements for new interchange proposals require that MDOT show that regional needs are not met with the existing interchanges to justify a new interchange. Preliminary input from FHWA indicated that there would have to be a compelling reason to allow a new interchange. This would be based on an extensive analysis that demonstrates a failure of the existing system to handle traffic demand. Analyzing the traffic volumes on I-75, merging traffic from on- and off-ramps, and the ability to clearly sign between the interchanges would also have to be completed and shown to be a minimal negative impact. MDOT must also show that the existing interchanges are optimized for today’s travel needs before a new interchange would be considered by FHWA.

The 2004 I-75 Gaylord East-West Crossing Study conducted by the Northeast Michigan Council of Governments looked at the possibility of adding interchange on I-75 at or near McCoy/Milbocker Road (listed as Alternative 2) and found that, while it would provide the “best benefit for commercial truck access into the industrial areas near the airport, it does not solve peak hour traffic congestion problems at the two existing I-75 interchanges.” According to MDOT’s most recent traffic volume counts (2021), a large majority of traffic on M-32 in Gaylord has an origin or destination on that corridor and is not “pass-through” traffic. For that reason, a significant traffic diversion off M-32 should not be expected with a new interchange at McCoy Road. The operations and capacity of the I-75 Business Loop (BL) from McCoy Road to the south interchange (Exit 279) via I-75 BL currently provides a very good level of service. The extra distance to travel from McCoy Road to the existing south interchange is not seen as significant. Currently, and using predicted traffic volumes for 2045 with modest expected improvements, the north interchange operates at an acceptable level of service. The south interchange operates at an excellent level of service.

A new interchange would be a substantial independent investment that is not seen to be feasible at this time due to high costs, right-of-way constraints, geometrics, limited physical space, and FHWA requirements. There are also safety and operational concerns with a new interchange that is only 1 mile away from an existing interchange. Any new interchange would be an independent project that is outside the purpose and need of the M-32 interchange reconstruction project. MDOT will continue to look at the safety and efficiency of the M-32 interchange as a secondary goal of the reconstruction project by investigating the feasibility of alternative designs, including both major changes and smaller improvements such as access control along surface streets, traffic signal control, modifying ramp terminals and intersections, adding turn bays, or lengthening vehicle storage. These are measures that will ensure this interchange meets the needs of regional traffic today and into the future. 

MDOT has held several meetings with a local advisory committee and the general public about this project, including:

• Monday March 3, 2023 – First Local Advisory Committee meeting
• Tuesday April 11, 2023 – First Public Open House
• Tuesday May 30, 2023 – Second Local Advisory Committee meeting
• Thursday September 21, 2023 – Third Local Advisory Committee meeting
• Tuesday October 24, 2023 – Second Public Meeting and Open House

More public and advisory committee meetings will be scheduled as the project continues to develop.

Note: The Public Advisory Committee consists of project stakeholders including local units of government, local law enforcement, regional law enforcement, state law enforcement, local business groups, local business leadership, local school representatives, hospital representatives, local economic development groups, recreational trail advocacy groups, emergency response organizations, airport representatives. This is in addition to local, regional, and statewide MDOT engineers and planners and Federal Highway Administration representatives. This group was formed to provide MDOT critical feedback throughout the project development schedule, ensure local interests are factored into decision making, and help guide our public outreach process.