Interstate 675 Michigan

I-675 Michigan
North End
South End


Interstate 675 constitutes an urban loop west from I-75 at Buena Vista Township to Downtown Saginaw. North from the city of Saginaw, I-675 separates Saginaw Township North and Carrollton Township to Tittabawassee Road. The freeway returns to Interstate 75 on the north side of Zilwaukee.


Designated in 1969, Interstate 675 was completed by 1971.1 The loop was initially considered as a reliever route for I-75 and the Zilwaukee Bridge, a bascule bridge spanning the Saginaw River. The Zilwaukee Bridge was a well known bottleneck along the drive between Detroit and northern Michigan, as the six-lane section of I-75 between Flint and Bay City narrowed to four lanes at the span. Openings along the old Zilwaukee Bridge often accommodated steel shipments from a General Motors plant in Saginaw.2

Construction got underway in 1979 to replace the bascule bridge along I-75 with a fixed, high-level span.3 During the same time steel shipments ceased from the General Motors plant.2 A major incident took place during work on the bridge when a 300 foot long section of the new deck tilted due to excessive construction loads. This pushed back completion of the Zilwaukee Bridge four years, which partially opened with two-way traffic on December 23, 1987. For a period of time, local drivers to displayed bumper stickers that read “I drove over the Zilwaukee Bridge AND LIVED!”. Locally referred to as the Z-Bridge, the new eight lane span was completed on September 19, 1988.2,3

Route Information

  • North End – Zilwaukee, MI

  • South End – Buena Vista, MI

  • Mileage – 7.70

  • Cities – Saginaw, Zilwaukee

  • JunctionsI-75

Source: December 31, 2018 Interstate Route Log and Finders List

I-675 Annual Average Daily Traffic (AADT)

North End I-75 US 23 – Zilwaukee, Michigan

Perspective from Interstate 675 north
Interstate 675 angles northeast from Tittabawassee Road through Kochville Township. Michigan Avenue spans the freeway 0.75 miles ahead of I-75 & U.S. 23. Photo taken 11/06/09.
Entering the trumpet interchange with Interstate 75 & U.S. 23 south through Zilwaukee and north to Bay City, Grayling and the Mackinac Bridge to the Upper Peninsula of Michigan. Photo taken 11/06/09.
Previous guide signs posted at the north end of Interstate 675. Photo by Thai Williams (2001).
Perspective from Interstate 75 & U.S. 23 north
I-75 and I-675 north converge at a trumpet interchange (Exit 155) just outside the Zilwaukee city limits. Photo by Eric Vander Yacht (2001).
Perspective from Interstate 75 & U.S. 23 south
Heading south into Saginaw County along Interstate 75 & U.S. 23, two miles out from the north end of I-675 (Exit 155). Photo taken 11/06/09.
I-75 was expanded from six to eight overall lanes leading south to Zilwaukee by 2012. A new overhead for Interstate 675 replaced this assembly during construction. Photo taken 11/06/09.
Exit 155 was expanded to a two-lane off-ramp for Interstate 675 south into Saginaw during I-75 expansion. Photo taken 11/06/09.

South End I-75 US 23 – Buena Vista Township, Michigan

Perspective from Interstate 675 south
Interstate 675 was reconstructed through Saginaw in 2009-10. Advancing east from Veterans Memorial Parkway, the freeway crosses into Buena Vista Township ahead of I-75 & U.S. 23. Photo taken 11/06/09.
A modified trumpet interchange joins the south end of I-675 with Interstate 75 & U.S. 23 south to Flint and north to Zilwaukee. Photo taken 11/06/09.
Perspective from Interstate 75 & U.S. 23 south
Interstate 675 south returns to I-75 & U.S. 23 one mile south of the dumbbell interchange (Exit 152) with M-81 (Washington Road). Photo taken 11/06/09.
An overhead replaced this ground level assembly at Exit 150 during reconstruction of I-75 at I-675 in 2014. Photo taken 11/06/09.