Michigan DOT Accelerates I-75 Reconstruction With New Delivery Methods
The Michigan Department of Transportation (MDOT) expects to complete the Interstate 75 Modernization Project 10 years ahead of schedule by employing alternative project delivery options.
"Stakeholders asked us to accelerate it, and that's what we have done," says Rob Morosi, Spokesperson for the department.
I-75 was designed in the 1950s and built in the 1960s and has had no major improvements since it was constructed. The freeway currently carries about 175,000 vehicles daily, with projections increasing to 193,000 vehicles per day in 2035. "This freeway has essentially reached its lifespan," Morosi says.
Shortening Delivery Time
The 18-mile-long freeway modernization in Oakland County aims to reduce overall costs and disruptions for drivers. The original plan called for a $1.3 billion project, delivered in nine segments during the even years for 17 years. But motorists, business people and civic leaders bulked at the lengthy time frame. It would hold up municipal construction projects and interfere with smooth motoring for years.
"People asked us to go back to the drawing board, and that's what we did," Morosi says.
The first $90.8 million segment was completed in 108 days. It began in 2016 and entailed replacing an overpass at Squirrel Road, rebuilding 3 miles of interstate, reconfiguring the Square Lake interchange, realigning left-lane entrances and exits with right-lane movements, replacing eight bridges, and improving drainage. It was opened to traffic ahead of schedule in September.
The remaining 15 miles will run from M-102 to north of Coolidge Highway. Work includes adding a peak-hour, nonbarrier, high-occupancy vehicle lane in each direction, interchange improvements, replacement of more than 40 bridges, and installation of new signs, noise walls and intelligent transportation systems. The road will have four lanes in each direction when completed. The department expects traffic to not only flow more smoothly but also to be safer for drivers.
MDOT divided the remaining project into two segments and is using two different delivery methods.
The Northern Segment
The 8-mile, $350 million northern segment runs from Coolidge to 13 Mile Road. It includes three of the original segments. It will be let as a design-build, using standard road and bridge federal and state funding. The project will improve geometrics, using standard reconstruction and expansion techniques. The project should let in summer 2018 and complete in 2020.
Design-build will allow engineering and construction to overlap, saving time. The contractor can use more innovation and draw on its expertise to enhance the design. The department has successfully used this delivery method in the past. Work will take place simultaneously with the southern section.
The Southern Segment
The 5.5-mile, $650 million southern section will be delivered using a design, build, finance and maintain method. It combines five of the original segments into one contract. This is the first time MDOT has used this public-private partnership delivery method to build a road.
"We just do not have that money up front," Morosi said. "We are looking for the private sector to come in and fund the project, and then they will be reimbursed with availability payments over the next 25 to 30 years, using existing program dollars."
The department has successfully used a public-private partnership in the past to upgrade lighting in the Detroit area, starting in 2015. That work included replacing damaged poles and converting 15,000 old sodium fixtures to LED fixtures. The contractor operates and maintains the lights for 13 years and is paid an availability payment. The $44 million in capital costs were financed entirely with private capital. The LED lighting has saved the department more than $1 million in energy costs.
One of the benefits of a contract that includes maintenance is the developer will typically take a whole-life approach. For instance, that might include selecting materials that increase the building cost but reduce long-term maintenance costs. The contract will require the road remain in good condition throughout the term, with no maintenance deferred.
The public-private partnerships will allow the department to leverage local contractor knowledge, while meshing with national developers and financial investors. Project risks are allocated to the parties best able to manage them.
MDOT expects to close in late fall 2018 on the southern segment and work to start in 2019. It is anticipated to finish in 2022. In addition to the funding, the department chose this delivery method for this segment, because it requires more innovation and has more challenges to construction than typical jobs.
"Over four miles is depressed freeway, below street level," Morosi says. "You are looking at not only road and bridge building, but you are looking at enclosed drainage, retaining walls and the interchange at 696 and I-75. You are looking at a more challenging rebuild."
Widening for Better Flood Preparation
Room exists in the right of way to widen the depressed highway. The current grassy slopes will be replaced with retaining walls.
The work includes installation of an approximately 40-foot-wide drainage tunnel from 8 Mile to 12 Mile Road along the northbound service drive. The tunnel will run about 100 feet underground. Morosi anticipates the contractor will bore the tunnel, which will be separate from local municipality's storm and sanitary sewer systems. The tunnel must be finished before the southern road segments. Some segments will be able to be constructed concurrently.
"It will be capable of handling major flood events," Morosi says. "It will be able to hold water and allow it to discharge incrementally and slowly during major rain events."
At the I-696 and I-75 interchange entrance ramps will be converted to a modern design. Currently both eastbound and westbound traffic converges into a single northbound I-75 lane, which drivers share with an exit-only ramp to 11 Mile Road.
"You have a conflict where you have traffic merging onto the freeway sharing a lane with an exit-only lane," Morosi says. "The braid will build a bridge, separating traffic entering the freeway from that exiting the freeway."
That should reduce accidents and let traffic flow more smoothly.
"We hope the public will see the short-term inconvenience will be worth it in the end," Morosi says.
Photos courtesy of Michigan Department of Transportation