DETROIT, MI When the Michigan Department of Transportation launches a two-year, $91 million project to start expanding and modernizing part of Interstate 75 north of Detroit, Michigan; it will also be starting something much larger.

Throughout the next 16 years, MDOT is planning a series of projects that are estimated to cost $1 billion and will leave Michigan with 18 miles of rebuilt I-75 in Oakland County. It will include a high-occupancy vehicle lane in each direction for vehicles carrying at least two people in peak travel times, and various other changes to improve traffic flow.

The work will also rebuild interchanges and freeway pavement, construct carpool lots, improve the drainage system, replace bridges, and add aesthetic enhancements to the corridor. 

The agency said the I-75 widening and reconstruction program has been in planning and development stages for nearly 20 years, to upgrade a highway that was built in the 1960s but has not received comprehensive corridor improvements since then. It now has a daily traffic volume of 103,000 vehicles to 174,000 vehicles.

"It is a critical commercial route, a key commuter route, a vital tourist route and a local area business route moving people and goods across the state daily," MDOT said.

The first phase will take on a segment between Coolidge Highway and South Boulevard. It involves rebuilding pavement, replacing bridges and modernizing the Square Lake Road interchange.

Crews began getting ready for that work early this year by removing trees and brush for a realignment of the highway. MDOT said crews were only removing vegetation that they had to clear, and would replace it when construction is completed. 

Plans call for each additional project to launch every two years, with the final one starting in 2030.