Interstate 675 (Michigan)
I-675 highlighted in red
|Auxiliary route of I-75|
|Maintained by MDOT|
|Length:||7.728 mi (12.437 km)|
|Existed:||1971 – present|
|South end:||I-75 / US 23 near Saginaw|
|M-58 in Saginaw|
|North end:||I-75 / US 23 in Zilwaukee|
Interstate 675 (I-675) is an auxiliary Interstate Highway in the US state of Michigan. The freeway is a 7.73-mile-long (12.44 km) loop route through downtown Saginaw as I-75 passes on the east side of the city. I-675 is also a state trunkline highway that provided a bypass of the former drawbridge carrying I-75 and US Highway 23 (US 23) across the Saginaw River. Construction of I-675 started in 1969 and the freeway opened in 1971. Since then, sections near downtown were reconstructed in 2009 through 2011 to update one of the freeway's interchanges and rebuild the bridge over the Saginaw River.
Route description 
I-675 splits from I-75 on the eastern side of Saginaw, turning west toward downtown. The freeway runs between residential neighborhoods and has an interchange with Veterans Memorial Parkway. West of that interchange, it crosses a line of the Huron and Eastern Railway. From there, it runs on the northern edge of downtown near the Dow Event Center, crossing the Saginaw River on the Henry Marsh Bridge. On the west side of the river, the trunkline meets an interchange with M-58. From there it turns northward, crossing a line of the Mid-Michigan Railroad. I-675 continues northward, passing to the east of the Aleda E. Lutz VA Medical Center and through more residential neighborhoods in Saginaw Township North. After the interchange with Tittabawassee Road, which provides access to the Fashion Square Mall, I-675 turns northeasterly to merge back to I-75 north of the Zilwaukee Bridge.
Like other state highways in Michigan, I-675 is maintained by the Michigan Department of Transportation (MDOT). In 2011, the department's traffic surveys showed that on average, 20,900 vehicles used the freeway daily across the river and 4,000 vehicles did so each day north of Tittabawassee Road, the highest and lowest counts along the trunkline, respectively. As an Interstate Highway, all of I-675 is listed on the National Highway System, a network of roads important to the country's economy, defense, and mobility.
The original bridge across the Saginaw River for I-75/US 23 at Zilwaukee was built in 1960 as a bascule bridge to allow shipping traffic to use the river. Opening the drawbridge would back traffic up on I-75/US 10/US 23 for upwards of four hours on holiday weekends, and I-675 was designed to help relieve the congestion. Approved in 1974, construction on the replacement bridge started in October 1979; I-675 served as an additional bypass route for traffic along the construction zone. A major construction accident in August 1982 delayed completion of the new Zilwaukee Bridge; a bridge pier partially collapsed when contractors overloaded a section under construction. The affected 300-foot (91 m) deck segment tilted to rest three feet (0.91 m) higher on one end and five feet (1.5 m) lower on the other. The structure was originally supposed to cost $76.8 million with a 1983 completion date; in the end it cost $131.3 million when the southbound span finally opened on September 19, 1988.
Starting in May 2009 and ending in November 2011, sections of I-675 were closed from exit 2 easterly to begin renovations during the summer construction seasons. These projects included rehabilitation of the Henry Marsh Bridge, the reconstruction of overpasses, and a redesigned exit at Warren Avenue to ease access into downtown Saginaw.
Exit list 
The entire highway is in Saginaw County.
|Buena Vista Township||0.000||0.000||—||I-75 / US 23 – Flint, Mackinac Bridge||Exit 150 on I-75/US 23|
|1||Veterans Memorial Parkway|
|2A||Wadsworth Avenue, 5th Avenue, 6th Avenue – Downtown Saginaw||Signed as exit 2 northbound|
|2.333||3.755||2B||Jefferson Avenue – Downtown Saginaw||Southbound exit and northbound entrance|
|3||M-58 (Davenport Avenue) / Michigan Avenue|
|Saginaw Township||5.854||9.421||6||Tittabawassee Road – Zilwaukee|
|Zilwaukee Township||7.728||12.437||—||I-75 / US 23 – Flint, Mackinac Bridge||Exit 155 on I-75/US 23|
See also 
- Michigan Department of State Highways (1971). Official Highway Map (Map). 1 in:14.5 mi. Section J12.
- Michigan Department of State Highways (1972). Official Highway Map (Map). 1 in:14.5 mi. Section J12.
- Michigan Department of Transportation (2009). MDOT Physical Reference Finder Application (Map). Cartography by Michigan Center for Geographic Information. http://www.mcgi.state.mi.us/prfinder/. Retrieved May 15, 2012.
- Michigan Department of Transportation (2012). State Transportation Map (Map). 1 in:3.5 mi / 1 cm:2 km. Saginaw inset.
- Google Inc. Google Maps – Overview Map of I-675 (Map). Cartography by Google, Inc. //maps.google.com/maps?saddr=Unknown+road&daddr=Unknown+road&hl=en&sll=43.47491,-83.917522&sspn=0.060043,0.058279&geocode=FZfBlgIdFub_-g%3BFTaylwIdnEv_-g&t=h&mra=ls&z=13. Retrieved July 12, 2012.
- Michigan Department of Transportation (January 2011) (PDF). Michigan's Railroad System (Map). http://www.michigan.gov/documents/MDOT_Official_Rail_130897_7.pdf. Retrieved February 1, 2011.
- Bureau of Transportation Planning (2008). "Traffic Monitoring Information System". Michigan Department of Transportation. Retrieved June 30, 2012.
- Michigan Department of Transportation (April 23, 2006) (PDF). National Highway System, Michigan (Map). Cartography by MDOT. http://www.michigan.gov/documents/MDOT_NHS_Statewide_150626_7.pdf. Retrieved October 7, 2008.
- Adderley, Kevin (August 26, 2010). "The National Highway System". Federal Highway Administration. Retrieved January 1, 2011.
- Michigan Department of State Highways (1969). Official Highway Map (Map). 1 in:14.5 mi. Cartography by H.M. Gousha. Section J12.
- Michigan Department of State Highways (1970). Official Highway Map (Map). 1 in:14.5 mi. Section J12.
- Burns, Gus (June 30, 2011). "Saginaw Interstate 675 Work: 1,000 Truckloads of Fill Sand, $14.4 million". The Saginaw News. OCLC 9872938. Archived from the original on July 12, 2012. Retrieved July 12, 2012.
- Hyde, Charles K. (1993). Historic Highway Bridges of Michigan. Detroit: Wayne State University Press. pp. 166–8. ISBN 0-8143-2448-7.
- Staff writer (September 19, 1988). "Zilwaukee Bridge Now Open North, South—Partly". Toledo Blade. p. 1. OCLC 12962717.
- Henson, Stacey (May 26, 2009). "Interstate 675 Closures Begin Today in Saginaw County". The Saginaw News. OCLC 9872938. Archived from the original on July 12, 2012. Retrieved October 10, 2011.
- Barber, Barrie (November 2, 2011). "MDOT Now Says I-675 Will Reopen Mid-Day". The Saginaw News. OCLC 9872938. Archived from the original on July 12, 2012. Retrieved July 12, 2012.
- I-675 at Michigan Highways
- I-675 at Michigan Highway Ends
- I-675 Michigan at AARoad's Interstate Guide
- I-675 Michigan at Kurumi