Construction is taking place on I-75 along an 18-mile stretch of I-75 in Oakland County, Michigan. The freeway was built in the 1960s and has not received comprehensive corridor improvements since that time. Now, it is in the midst of a modernization project.

The average daily traffic amount at the most congested section of I-75 is 174,000. Much of the traffic is related to the automobile industry as 65 percent of automotive suppliers are headquartered in Oakland County. Three miles east and west of I-75 is home to 23,000 business and over 330,000 jobs. According to the Michigan Department of Transportation (MDOT), I-75 is a critical commercial route, a key commuter route, a vital tourist route, and moves people and goods across the state daily.

I-75 is not able to handle the massive amount of traffic that uses it these days. The need for increased capacity to relieve congestion is driven by the growth along the corridor due to land use changes and the migration of people, services, and industry.

In addition, it has become a safety hazard as there are nearly 1,000 crashes a year on the corridor. MDOT conducted a five-year crash data analysis and found that 55 percent of the crashes are rear end collisions, and 70 percent occur in dry conditions. “Our engineers reviewed the study and the data supported that there was a capacity issue,” says Rob Morosi, a Communications Specialist with MDOT.

In addition to the capacity issue, this section of I-75 has deteriorated and a new pavement was needed.

The Approach

Adding a fourth lane along 18 miles of freeway along with rebuilding the pavement of the current lanes and 47 bridges is clearly a huge undertaking. MDOT considered doing the project via the traditional design-bid-build method. They found that if it proceeded this way, the project would have been done in nine separate segments and taken over 18 years.

The department was not content with this timeline. “So we looked at ways to accelerate the project and found one which leverages innovation and uses our limited funding more efficiently,” says Morosi. MDOT settled on an approach that would condense the work into three segments and would be completed in 10 years. It involves innovative financing and will lead to a substantial cost savings.

The overall expected cost for the project is $1.7 billion. Segment one, which is already complete, cost $91 million and was constructed via design-build contract. It was paid for by a combination of federal and state dollars. Segment two, which cost $ 224 million, was financed the same way.

Segment three of the modernization project is the most complex section. Construction costs alone for this segment are $630 million. “We knew we had to be innovative in terms of financing to get this done,” says Morosi.

This segment of the project is being financed via a public-private partnership or P3. The winning bid for the project was submitted by Oakland Corridor Partners (OCP). It has both a financial and construction arm, and their primary equity partners are the John Laing Group and AECOM Capital. The construction team is made up of local contractors including Dans Excavating Inc, Ajax Paving Industries, C. A. Hull, and Jay Dee Constructors. OCP is responsible for constructing the project over a five-year period and then will handle all maintenance except for snow removal.

OCP provided the upfront capital for segment three. The state of Michigan, however, is retaining ownership of the area. The state began making fixed payments in 2018 of $50 million annually and will do so through 2048. According to Morosi, that is 5 percent of MDOT’s overall budget. He said of the arrangement, “The key was to transfer more risk to the private sector and provide a cost benefit for the public.” Morosi adds, “There are many stipulations, so the public is protected.”

Project Components

Segment one is the far northern segment. It involved adding a lane on each direction, rebuilding 3 miles of freeway, six bridges, and reconstructing an interchange. It began in August 2016 and was complete in September 2017.

Segment two combined three separate contracts into one and is taking place over 8.5 miles of freeway and includes 18 bridges. Two interchanges are being turned into diverging diamond interchanges, which MDOT believes will improve both vehicle and pedestrian safety.

Pre-stage construction on segment two began in the fall 2018. In spring 2019, northbound traffic was shifted to the south side of the freeway. Because of usage of shoulders, MDOT was able to arrange two lanes in each direction on the south side. This stage was completed in late 2019. Work in 2020 is focusing on rebuilding southbound pavement and bridges with all traffic shifted onto the newly constructed northbound lanes until the end of the calendar year. Final completion of the segment is expected in mid-2021.

Segment three began in January, with an expected completion date of fall 2023. It is shorter than segment two at 5.5 miles, but it is much more complex. “It’s the most challenging portion of the project because it’s below grade, and there are more issues to deal with,” says Morosi.

Those issues include drainage, utilities, and overpasses. There are 22 overpasses as compared to just three in the first two segments combined. Construction of 21,000 feet of retaining/noise walls is taking place. There are already some in the area, but they are being reconstructed.

Construction of a new tunnel, which is being built to collect stormwater and control drainage, is a great challenge. The tunnel will allow all the stormwater from I-75 to be separated from the municipal system, which will alleviate flooding on the freeway and in the neighborhoods.

The 4-mile long drainage tunnel is being built 100 feet below the northbound service drive that runs adjacent to the below grade freeway. It will be 14.5 feet in diameter and have the capacity to hold up to 26.5 million gallons of stormwater. “We’re confident that the tunnel will be a tremendous help for freeway traffic and for the community,” says Morosi.

Currently, there are seven pump stations that take water from the highway to the community stormwater system. The way the system works now often leads to flooding during storms. The new system will be able to store and discharge water at a reduced rate into the drain for the community, so it won’t be overwhelmed. There will be a centralized system to control discharge of the rainwater.

Finally, MDOT is installing an Intelligent Transportation System (ITS). It will provide real time information, enhance and expand capability of emergency response, and allow cars to talk to the infrastructure. The area is a perfect testing grounds for a futuristic system. “With so many automobile suppliers in the area, they can do all their testing on the corridor,” says Morosi.

When the I-75 modernization project is complete, commuters will enjoy a safer, smoother, and faster ride. Flooding will be alleviated, interchanges will be improved leading to an uptick in vehicle and pedestrian safety, and commuters will be able to turn to the ITS. “We’re taking a freeway designed in the 60’s and bringing it up to modern standards,” says Morosi.