Interstate 75 in Michigan
I-75 highlighted in red
|Maintained by MDOT|
|Length:||395.54 mi (636.56 km)|
|Existed:||1959 – present|
| Lake Erie Circle Tour
Lake Huron Circle Tour
Lake Michigan Circle Tour
Lake Superior Circle Tour
|South end:||I-75 near Erie at the Ohio state line|
|US 2 in St. Ignace|
|North end:||International Bridge in Sault Ste. Marie|
|Counties:||Monroe, Wayne, Oakland, Genesee, Saginaw, Bay, Arenac, Ogemaw, Roscommon, Crawford, Otsego, Cheboygan, Emmet, Mackinac, Chippewa|
Interstate 75 (I-75) is a part of the Interstate Highway System and runs from Miami, Florida, to Sault Ste. Marie in the Upper Peninsula of Michigan. I-75 enters Michigan from Ohio in the south, just to the north of Toledo and runs generally north through Detroit, Pontiac and Bay City, crosses the Mackinac Bridge, and ends at the Canadian border in Sault Ste. Marie. The freeway runs for approximately 395 miles (636 km) on both of Michigan's peninsulas. The landscapes traversed by I-75 include Southern Michigan farmland, northern forests, suburban bedroom communities, and the urban core of Detroit. The freeway also uses three of the state's monumental bridges to cross major bodies of water. There are four auxiliary Interstates in the state related to I-75, as well as nine current or former business routes, with either Business Loop I-75 (BL I-75) or Business Spur I-75 (BS I-75) designations.
The freeway bears several names in addition to the I-75 designation. The southern segment was called the Detroit–Toledo Expressway during planning in the 1950s and 1960s. Through Detroit, I-75 is the Fisher Freeway or the Walter P. Chrysler Freeway, named for pioneers in the auto industry. Sections on either side of the Mackinac Bridge are the G. Mennen Williams Freeway or the Prentiss M. Brown Freeway, named for politicians that helped get the bridge built. Officially, the entire length is the American Legion Memorial Highway. Various sections carry components of the four Great Lakes Circle Tours in the state.
Several Indian trails spanned the state along the general path of the modern freeway. After statehood, several of these were converted into plank roads that later became some of the first state highways. In the 1920s, five of these were added to the United States Numbered Highway System: US Highway 2 (US 2), US 10, US 24, US 25, and US 27. In the 1950s, a Michigan Turnpike was proposed as a tolled, controlled-access highway in the Lower Peninsula. After passage of the Federal Highway Act of 1956, this turnpike proposal was shelved as a free Interstate Highway was planned. Construction started in 1957, signs went up in 1959, and I-75 was completed in 1973. Since completion, the freeway has been upgraded with the construction of the Zilwaukee Bridge near Saginaw and improved connections to the Ambassador Bridge in Detroit.
Route description 
Known as "Michigan's Main Street", I-75 is listed on the National Highway System (NHS) for its entire length. The NHS is a network of roadways important to the country's economy, defense, and mobility. The freeway is the busiest in the state: between M-8 (Davison Highway) and McNichols Road approximately 194,300 vehicles used the freeway on average each day in 2010; in contrast the lowest traffic level was 3,208 vehicles between the M-48 and M-80 interchanges in Chippewa County. I-75 carries segments of all four Great Lakes Circle Tours in the state. It is also the only highway located on both Michigan's Upper and Lower peninsulas (UP and LP, respectively).
Lake Erie shore and the Downriver communities 
Crossing the state line north of Toledo, Ohio, I-75 enters Michigan in Monroe County carrying the Lake Erie Circle Tour (LECT) near the North Maumee Bay of Lake Erie. The freeway runs parallel to the shoreline of the Great Lake and past the community of Luna Pier. Further north, I-75 bypasses southeast of Monroe and crosses the River Raisin between the city and the river mouth. North of the river, the freeway turns further inland running through farmland. Near Newport, I-275 splits off to the northwest and I-75 continues its northeasterly trek through Monroe County. When it crosses the Huron River, the trunkline passes into Wayne County between South Rockwood and Rockwood.
On the north side of the county line, I-75 begins to run inland of, and parallel to, the Detroit River, entering the Downriver area. The freeway turns northerly after the interchange with M-85 (Fort Street) near Gibraltar, and the LECT departs I-75 to follow M-85 north of the interchange. The landscape transitions to suburban residential areas instead of farmland through this area. The freeway turns back northeasterly in Taylor and intersects the southern end of M-39 (Southfield Highway) in Lincoln Park. I-75 crosses the Ecorse River and passes through an industrial area of Metro Detroit. Further north, the freeway crosses the River Rouge in the southern part of Detroit.
I-75 runs parallel to M-85 (Fort Street) and follows the Detroit River as far east as the Ambassador Bridge. Near the bridge's approaches, the freeway turns 90° away from the river and intersects the eastern end of I-96 before turning again to parallel the river further inland. From there, I-75 meets M-10 (Lodge Freeway) and crosses under M-1 (Woodward Avenue). East of Woodward, the freeway runs past both Comerica Park and Ford Field, homes of the Detroit Tigers and Detroit Lions professional sports teams, respectively.
Detroit to the Tri-Cities 
Immediately east of Ford Field, I-75 turns northwesterly to follow the Chrysler Freeway away from the downtown Detroit area. The transition from the Fisher Freeway involves a set of one-lane ramps through the interchange with the connections to Interstate 375 and M-3 (Gratiot Avenue). Heading north-northwesterly, I-75 passes to the east of the campus of Wayne State University and through an interchange with I-94 (Edsel Ford Freeway). The Chrysler Freeway passes to the west of Hamtramck and to the east of Highland Park, enclaves within Detroit. I-75 meets M-8 (Davison Freeway) and continues through residential areas of Detroit's northern side. North of M-102 (8 Mile Road), the freeway crosses out of Detroit and into Oakland County. The Chrysler Freeway runs through the suburb of Hazel Park, site of the "worst freeway for accidents in Metro Detroit" at a curve near 9 Mile Road.
Further north, I-75 intersects I-696 near 10 Mile Road. The freeway continues northward for about six miles (9.7 km) into Troy, where it turns westward. The route for I-75 zig-zags through Troy and Auburn Hills as the freeway alternates from north–south to east–west to bypass Pontiac. Near the M-59 interchange, I-75 passes the headquarters for Chrysler. Further north, by the M-24 interchange, it runs near The Palace of Auburn Hills, home of the Detroit Pistons. The freeway passes through additional suburban residential areas as it runs northwesterly away from Pontiac. These subdivisions end north of Clarkston, which is the location of the northern terminus for US 24. Continuing through Holly and Newark, the freeway transitions back to a rural, wooded setting.
As I-75 approaches Grand Blanc, the landscape changes back to suburbs. I-475 (UAW Freeway) splits off to the north to bypass the east side of Flint, and I-75 merges with US 23 to turn northerly to run around the west side of the city. I-75/US 23 meets I-69 near the Bishop International Airport southwest of downtown Flint. The freeway continues northward along the western residential neighborhoods, meeting the northern end of I-475 near Mount Morris. I-75 passes to the west of Clio and the east of Birch Run, the latter home to a large outlet mall. From there, the trunkline passes through farmland in southern Saginaw County.
Central Michigan 
I-75/US 23 enters the southern reaches of the suburban Tri-Cities at Bridgeport and runs northward through the area. The freeway passes to the east of downtown Saginaw. I-675 splits off to run westward into downtown, and I-75 curves around to the northwest to cross the Saginaw River on the Zilwaukee Bridge in the suburb of Zilwaukee. North of the river, I-675 reconnects to I-75, and the latter freeway runs northward into Bay County. The freeway passes to the west of Bay City, encountering the eastern end of the US 10 freeway. From there, I-75/US 23 curves northwesterly to bypass Kawkawlin before running north to the Standish area through farmlands inland from the Saginaw Bay. West of Standish, US 23 splits to run along the Lake Huron shoreline, and I-75 turns northwesterly to run inland.
West of Sterling, the landscape changes again; in this area the freeway passes into forest lands. I-75 continues northwestward through Arenac County and crosses into western Ogemaw County. M-30 passes under the freeway without an interchange as I-75 passes to the west side of West Branch. On the northwest side of that city, M-55 merges onto I-75, and the two highways turn to run concurrently westward into Roscommon County. East of Prudenville, M-55 splits from the freeway. I-75 turns northward to run to the east of Houghton and Higgins lakes. Turning back to the northwest, the trunkline bypasses Roscommon to the south and crosses into southern Crawford County. About five miles (8.0 km) north of the county line, I-75 meets the northern end of US 127, the former US 27.
Northern Michigan 
After the US 127 interchange, I-75 turns northward, and passes to the east of Grayling. There are a pair of interchanges on either end of town for BL I-75, and the southern one is a partial interchange; only northbound I-75 traffic may access the business loop and traffic entering the freeway may only access southbound I-75. There is no interchange further north for M-72; access to that highway is provided through the business loop. On the north side of Grayling, there is a full interchange for BL I-75/M-93 that provides the southbound I-75 connection to M-72 as well as access from both directions to the Hartwick Pines State Park.
Crossing into southern Otsego County, I-75 continues northward through Northern Michigan forests. It passes to the east of the community of Waters and Otsego Lake. North of exit 279, I-75 passes the Gaylord Regional Airport and crosses the 45th Parallel, the halfway mark between the Equator and the North Pole by latitude. The freeway then passes through the west side of Gaylord and continues through forests in the northern sections of the county. North of Vanderbilt, I-75 crosses into southern Cheboygan County, assuming the G. Mennen Williams Freeway name.
I-75 runs northward through Cheboygan County, passing Indian River and crossing the river of the same name. North of town, the freeway passes through the area between Burt and Mullett lakes before intersecting the southern end of M-27; that highway provides access to Topinabee and Cheboygan. I-75 continues northward through tree farms and other agricultural properties in rural Cheboygan County. Cheboygan is accessible by way of interchanges for C-64 and C-66, a pair of county-designated highways in this area. North of C-66, I-75 turns northwesterly. The freeway meets the northern end of US 31 and picks up the Lake Michigan Circle Tour (LMCT) designation before crossing into Emmet County on the south side of Mackinaw City. I-75 then runs northward parallel to the county line on the west side of the village, meeting the northern end of US 23. After that interchange, the Lake Huron Circle Tour (LHCT) merges in from the south. There is one more interchange along the freeway before I-75 ascends the approaches to the Mackinac Bridge.
Mackinac Bridge 
The Mackinac Bridge carries I-75 across the Straits of Mackinac that separate Michigan's Upper and Lower peninsulas; the straits also form the connection between Lakes Michigan and Huron. The structure, unlike the rest of the state highways in Michigan like I-75, is under the maintenance and control of the Mackinac Bridge Authority (MBA).[a] The authority collects a toll from traffic that crosses the bridge, which as of January 1, 2012[update], is $4 for passenger cars and $5 per axle for commercial vehicles and motorhomes. In addition to cash, the MBA offers a pre-paid debit card option for the payment of tolls. The authority also provides a driver assistance program that will drive vehicles across the bridge at no additional charge; motorists who use the service have a fear of bridges. Because the bridge normally only allows motor vehicles, bicyclists and snowmobiles shuttled across are subject to fees. The authority maintains a small police department to patrol the bridge and escort vehicles across, and a pair of radio station transmitters that broadcast bridge conditions and travel information on AM 530 and AM 1610.
Upper Peninsula 
North of the Mackinac Bridge, I-75 passes to the west of downtown St. Ignace, passing between the Father Marquette National Memorial and the Straits State Park. There is an interchange north of the toll plaza that marks the eastern end of US 2 in the state. The LMCT departs I-75 to follow US 2 while the LHCT follows BL I-75 through town. The freeway curves around the Mackinac County Airport and meets the northern end of the business loop near Castle Rock; the LHCT returns to I-75 at that interchange as well. M-123 (Tahquamenon Trail) intersects from the west as the freeway parallels H-63 (Mackinac Trail), the former route of US 2. I-75 crosses the Carp River and runs along St. Martin Bay before meeting M-134. At that interchange, the LHCT departs again to run eastward. Through this area, the freeway runs northeasterly, passing through the Eastern Unit of the Hiawatha National Forest.
I-75 crosses the Pine River before passing into Chippewa County. The freeway takes a more northerly track as it crosses under M-48 without an interchange. Further north, M-48 curves around to connect I-75 with Rudyard, and the freeway turns back to run northeastward. About five miles (8.0 km) northeast of Rudyard, I-75 passes next to Chippewa County International Airport, the former Kincheloe Air Force Base in Kinross and Kincheloe. North of there in Dafter, the freeway intersects M-28 (9 Mile Road). Beyond that interchange, I-75 picks up the Lake Superior Circle Tour (LSCT) designation, which it carries the rest of the way north. On the south side of Sault Ste. Marie, the freeway meets BS I-75 and picks up the LHCT designation one more time. I-75 runs around the west side of the city, passes the Sault Ste. Marie Municipal Airport and the campus of Lake Superior State University before meeting the customs and toll plazas for the International Bridge. From there, I-75 crosses the two-lane bridge and terminates at the Canadian border. As of October 1, 2012[update], the toll rates on the bridge are $3 for passenger vehicles, $2.10 for commuters, and $4 per axle for commercial vehicles; currently the same toll rate is assessed in U.S. dollars and Canadian dollars. Motorists have the option to pay with cash or an IQ Card, an electronic toll collection debit card that uses radio-frequency identification technology.
Indian trails to state highways 
Before Michigan became a state, the first land transportation corridors were the Indian trails. The French-Indian Trail ran through southeastern Michigan between Toledo, Monroe and Detroit. The Saginaw Trail ran north from Detroit to the Saginaw area where it connected with the original Mackinaw Trail that ran roughly parallel to, and west of, the modern I-75. Another path, the Cheboygan Trail, ran parallel to the modern freeway to the east between the West Branch area and Cheboygan. In the UP, an extension of the Mackinac Trail connected St. Ignace and Sault Ste. Marie. In the 19th century, the Michigan Legislature chartered private companies to build and operate plank roads or turnpikes in the state, many of which replaced the original Indian trails. These roads were originally made of oak planks, but later legislation permitted gravel as well. By the first decade of the 20th century, only 23 of the 202 chartered turnpikes were still in operation; many companies that received a charter never built their specified roadways. The remaining plank roads were turned over to the state or purchased by railway companies in the early part of the century.
The State Trunkline Highway System was formed on May 13, 1913, and several sections of the system were designated along the course of the then-future I-75. Division 1 connected the Ohio state line northeasterly to Detroit, and Division 2 connected Detroit with Mackinaw City. A branch of Division 7 ran north from St. Ignace to Sault Ste. Marie. The system was signposted in 1919, and those highways were marked on maps for the first time. The first M-10 was designated along the highways from Ohio through Detroit to Standish.[b] M-76 connected Standish with Grayling, where the first M-14 ran northward to Cheboygan. From there, M-10 connected to Mackinaw City. In the UP, M-12 connected St. Ignace with Sault Ste. Marie along a route to the east of the old Mackinac Trail. When the United States Numbered Highway System was formed on November 11, 1926, most of these highways were redesignated as part of the national system. From the state line northward, M-10 was included as a part of US 24 and US 25. At Detroit, M-10 was used as a part of US 10. North of Grayling, M-14 was redesignated as a part of US 27. M-12 was used for US 2.
The Michigan State Highway Department (MSHD)[c] rerouted US 2 in 1933 between Rogers Park and Sault Ste. Marie. The new routing followed Mackinac Trail instead of turning east to Cedarville and north to Sault Ste. Marie; the former routing was given the M‑121 designation.
Turnpikes and freeways 
By 1945, a divided highway designated Alternate US 24 (ALT US 24) was opened from the state line north to Erie. After World War II, the MSHD planned to convert several highways in the state to freeways. In planning maps from 1947, the modern I-75 corridor was included in the system that later became the Interstate Highway System. It was also included in the General Location of National System of Interstate Highways Including All Additional Routes at Urban Areas Designated in September 1955, or Yellow Book after the cover color, that was released in 1955 as the federal government readied plans for the freeway system.
The Michigan Turnpike Authority (MTA), an agency which was created in 1951, proposed the construction of a toll freeway to run north–south in the state. The original termini for the turnpike were Bridgeport and Rockwood. The legislation creating the authority was upheld by the Michigan Supreme Court in a lawsuit in 1955. The original planning maps plotted the turnpike to the west of Detroit, running near US 24 (Telegraph Road). This route was later proposed for I-75 itself; I-275 would have been the freeway to loop into downtown Detroit. The state highway commissioner at the time, Charles Ziegler, distrusted a separate agency dealing with statewide road building at the time, and he worked to stall progress on any proposed turnpikes. The proposed length was increased by December 1955; the extended Michigan Turnpike would have run from a connection across the Ohio state line to Toledo north through Detroit and Saginaw and eventually to the southern end of the Mackinac Bridge. By the following April, any extensions were cancelled leaving the turnpike to its original termini. The MTA moved forward in 1957 on a bond sale to finance construction of the roadway, but when the federal government approved the Federal Aid Highway Act of 1956, Ziegler and the MSHD announced plans for a full freeway to run north through the Lower Peninsula and continue across to the Upper Peninsula. This announcement undermined the efforts to build the Michigan Turnpike. In August 1956, the MTA voted to reduce its operations to a skeleton staff, and in 1962, the Michigan Legislature voted to repeal the act that created the MTA.
Interstate Highway era 
The first sections of freeway for I-75 were opened in 1957. The southern section near the Ohio state line opened in October 1957. The Mackinac Bridge was opened to traffic on November 1, 1957; a new section of freeway and an interchange connected US 2 to the bridge. The MSHD formally proposed the I-75 number in 1958. On June 30 of that year, the first stretch of the "Fenton–Clio Expressway" opened, stretching from Fenton to Birch Run. Construction on the Chrysler Freeway in Detroit started on January 30, 1959. The I-75 signs were first installed along the Detroit–Toledo Expressway in October 1959, replacing US 24A signage in the Monroe area, after the state waited for final approval of the numbering system to be used in the state.
In November 1960, sections of freeway opened from Indian River north to the southern Mackinac Bridge approaches in Mackinaw City and from St. Ignace to Evergreen Shores, and by December, the section of freeway running between Evergreen Shores and M‑123 was scheduled to open. The next year the original Zilwaukee Bridge, a bascule bridge across the Saginaw River was opened along with a section of freeway north to Kawkawlin. That September, the section between Gaylord and Vanderbilt was completed, and in October 1961, the first segment of I-75 near Grayling opened, connecting M-18 with the city. By the end of the year, the freeway was completed between Kinross and Dafter in the UP. and the former segment of US 27 between Grayling and Gaylord was turned back to local control. After this individual segment of freeway was completed, it left a gap between Gaylord and Indian River that was designated "TO I-75" on maps for the former segment of US 27, and US 27 was truncated to about five miles (8.0 km) south of Grayling. The 12-mile (19 km) section of I-75 was opened between Gaylord and Waters in July 1962. Another temporary "TO I-75" designation was applied along US 10 and US 27 from Bay City to Grayling.
On October 25, 1962, the section of freeway from M-24 near Pontiac to the Flint area opened. The same year, the freeway gap was filled in between Gaylord and Indian River. The International Bridge and its approaches opened in Sault Ste. Marie on October 31, 1962. The following year, a set of segments opened in the Detroit area. The freeway was extended south from Pontiac to 11 Mile Road with a connection along M-150 to M-102 (8 Mile Road). Another section opened to connect with US 24 (Telegraph Road) in the Woodhaven area; a TO I-75 designation was added to connect along US 24 and M-102 to M-150. On the other end of the state, the gaps in the freeway across the UP were completed in 1963 as well, and the section of freeway in Northern Michigan was named the most scenic new highway in the US in 1963 by Parade magazine. The first part of the Chrysler Freeway opened to traffic on June 26, 1964, the southern mile (1.6 km) of which was designated I-375.
The segment of I-75 through the Downriver suburbs of Detroit between the US 24 (Telegraph Road) connector and M-39 (Southfield Highway) was completed in 1965. The next year, I-75 was extended south from 11 Mile Road to M-102 (8 Mile Road). In 1967, two segments of freeway opened. One was signed initially as a part of US 23 only from Kawkawlin to Standish, and the other through Detroit extended I-75 parallel to Fort Street. The Chrysler Freeway through Detroit was finished in 1968, and additional segments of the Fisher Freeway west of downtown Detroit were finished as well. The same year, the first section of M-76 was converted to a freeway from Standish northwesterly to Alger.
In 1970, I-75 through Detroit was completed, and two additional sections of M-76 were converted to freeway. The northern section ran from the US 27-to-I-75 transition south of Grayling to the Crawford–Roscommon county line, and the second was an extension from Alger to the West Branch area. The first ice-detection system in the state was installed on the River Rouge bridges in the Detroit area in an attempt to maximize driver safety.  The next year, the last section of the Chrysler Freeway in Hazel Park was finished when an interchange for the then-unbuilt I-696 was completed. Another segment of the M-76 freeway was completed at the same time, bypassing Roscommon. The final section between Alger and Roscommon was opened on November 1, 1973, in a dedication by Governor William G. Milliken, and the temporary TO I-75 on US 10 and US 27 was removed.
Since the freeway was completed, a few changes have been made to I-75 in Michigan. MDOT truncated US 2 to end in St. Ignace by removing it from the I‑75 freeway in 1983. In 1986, US 10 was truncated to Bay City, removing its concurrency with I-75 from there to Clarkston. Two years later, the original bascule Zilwaukee Bridge across the Saginaw River was replaced by a much higher structure slightly north of the former bridge.
Beginning on February 25, 2008, I-75 closed completely to traffic in both directions from Rosa Parks Boulevard (exit 49) to Clark Street (exit 47) in Detroit. This facilitated the complete rebuilding of the road as part of the Ambassador Gateway Project to better connect I-75 and I-96 to the Ambassador Bridge. Through traffic on I-75 was rerouted along I-94 to I-275 and local detours were posted. The freeway reopened to traffic in June 2009, five months ahead of schedule. The overall project to realign and connect the bridge to the freeways was mired in lawsuits between MDOT and the private company that owns the bridge. The company's owner was jailed for contempt of court during court proceedings in early 2012. MDOT was later ordered to assume responsibility for construction, and the department completed the project on September 21, 2012.
Freeway names 
I-75 has five named segments in Michigan. The southernmost section from the state line north to the Detroit area is the Detroit–Toledo Expressway. The segment through southern and central Detroit is known as the Fisher Freeway. It was dedicated on September 17, 1970, to the Fisher Brothers, who founded Fisher Body later a part of General Motors. After the curve in downtown Detroit, I-75 follows the Walter P. Chrysler Freeway northward. That segment is named for Walter P. Chrysler, founder of Chrysler. The name was chosen by the Detroit Common Council on November 6, 1957, and codified in state law in 1990; the state definition for the name places the northern end of the designation at the Oakland–Genesee county line.
Officially, the entire length of I-75 in Michigan is the American Legion Memorial Highway. As a practical matter, this name is not used on the southernmost segments of the Interstate. The American Legion was honored with the designation in 1969 in a state law that required private interests to finance the signage. Public Act 174 of 1984 redesignated I-75 in honor of the group and placed responsibility for signage in MDOT's hands. Two other segments near the Straits of Mackinac were named in 1976 for figures instrumental in the construction of the Mackinac Bridge. From the Cheboygan–Otsego county line north to the bridge, I-75 was named for G. Mennen Williams, the former governor once called "Michigan's Politician of the Century" in the press. The section in Mackinac County from the northern end of the Mackinac Bridge was also named for Prentiss M. Brown, the former Congressman and Senator who served on the Mackinac Bridge Authority Board until his death in 1971.
Monumental bridges 
Along its route in the state, I-75 utilizes three of Michigan's monumental bridges. The first of them is the Zilwaukee Bridge near Saginaw. The original bridge across the Saginaw River 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. Approved in 1974, construction on the replacement bridge started in October 1979. 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 (equivalent to $408 million in 2010) when the southbound span finally opened on September 19, 1988. The structure is the largest concrete segmental bridge in the United States.
The second is the Mackinac Bridge that connects Michigan's two peninsulas at the Straits of Mackinac. A structure was first proposed in 1888 by one of the directors of the Grand Hotel on Mackinac Island. Car ferry service was started in 1923 to cross the straits, and a bridge authority was first created in 1934 to investigate the possibility of building a permanent connection across the straits. This early authority started with a 1921 proposal for a series of bridges that would have connected Cheboygan to St. Ignace by way of Bois Blanc, Round, and Mackinac islands. The federal Public Works Administration rejected loan and grant requests for that project. A second, direct crossing was then proposed based on designs used for the Tacoma Narrows Bridge. The collapse of that bridge and World War II delayed any further work on a structure beyond tests of the lake bottom and the construction of the 4,200-foot-long (1,300 m) causeway on the St. Ignace side; the first bridge authority was abolished in 1947. The current agency was created on June 6, 1950.
The MBA was authorized in 1952 to sell bonds to finance construction, which were sold on December 17, 1953, to finance the $99.8 million (equivalent to $1.97 billion in 2010) cost of the bridge. The structure was designed by David B. Steinman and built by Merritt-Chapman & Scott for the substructure and the American Bridge Company division of U.S. Steel Corporation for the superstructure. Construction started in 1954 and the Mackinac Bridge opened to traffic on November 1, 1957. Final work on the bridge was completed in September 1958. Overall, the structure has a 3,800-foot (1,200 m) central suspension span flanked by two 1,800-foot (550 m) side spans. With the two backstay spans, the Mackinac Bridge is 8,614 feet (2,626 m) long between cable anchorages, the longest in the world at the time it opened.[d] The total length of the structure is 26,444 feet (8,060 m) with two 555-foot-tall (169 m) towers and 155 feet (47 m) of clearance for passing ships under the main span. In 2010, the structure was named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.
The northernmost of the three monumental bridges along I-75 is the International Bridge, linking the twin cities of Sault Ste. Marie in Michigan and Ontario. The governments on each side of the international border formed a bridge authority to build a highway bridge in 1935. Construction started on the structure September 16, 1960. The International Bridge is nearly three miles (4.8 km) long encompassing spans over the American and Canadian navigation channels for the Soo Locks and the St. Mary's River. The American approach is 2,471 feet (753 m), and the Canadian approach is 2,942 feet (897 m). The center span over the river is 9,280 feet (2,830 m), flanked by 1,260-foot (380 m) and 830-foot (250 m) spans over the American and Canadian shipping channels, respectively. The bridge was designed by the same firm that handled the Mackinac Bridge for a cost of $20 million (equivalent to $298 million in 2010). It opened to traffic on October 31, 1962.
Exit list 
||Erie Township||0.00||0.00||I-75 / LECT south – Toledo||Ohio state line; LECT continues south into Ohio|
|1.66||2.67||2||Summit Street||Southbound exit and northbound entrance|
|2.49||4.01||2||Erie, Temperance||Northbound exit and southbound entrance; unsigned CONN M-125|
|4.60||7.40||5||Erie Road – Erie, Temperance|
|Luna Pier||5.78||9.30||6||Luna Pier|
|La Salle Township||8.62||13.87||9||South Otter Creek Road – La Salle|
|Monroe Charter Township||11.36||18.28||11||La Plaisance Road – Downtown Monroe|
|Monroe||13.45||21.65||13||Front Street – Monroe|
|Frenchtown Charter Township||15.21||24.48||15||Dixie Highway – Downtown Monroe||Former M-50|
|20.26||32.61||20||I-275 north – Flint||To Detroit Metro Airport|
|Berlin Charter Township||21.45||34.52||21||Swan Creek Road – Newport||To Newport Road|
|South Rockwood||26.32||42.36||26||South Huron River Drive – South Rockwood|
||Rockwood||26.93||43.34||27||North Huron River Drive – Rockwood|
|Brownstown Charter Township||27.96||45.00||28||M-85 north (Fort Street) / LECT||Northbound exit and southbound entrance; southern terminus of M-85 and northern end of LECT concurrency|
|Flat Rock||28.80||46.35||29||Gibraltar, Flat Rock||Signed as exits 29A (Gibraltar) and 29B (Flat Rock) southbound|
|Woodhaven||31.79||51.16||32||West Road||Signed as exits 32A (east) and 32B (west)|
|Brownstown Charter Township||33.67||54.19||34A||To US 24 (Telegraph Road)||Southbound exit and northbound entrance|
|34.00||54.72||34B||Sibley Road, Dix Highway||Signed as exit 34 northbound|
|Taylor||35.06||56.42||35||US 24 (Telegraph Road)||Northbound exit and southbound entrance|
|Taylor–Southgate city line||37.06||59.64||37||Allen Road, Northline Road|
|Lincoln Park||39.84||64.12||40||Dix Highway|
|40.67||65.45||41||M-39 (Southfield Road)|
|Detroit||43.13||69.41||43||M-85 (Fort Street) / LECT / Schaefer Highway||Signed as exits 43A (south) and 43B (north) southbound; former northern terminus of M-85; southern end of LECT concurrency|
|44.83||72.15||44||Dearborn Street||Northbound exit and southbound entrance|
|45.57||73.34||45||M-85 (Fort Street) / Springwells Street|
|47.42||76.32||47A||Clark Street||Former M-3; signed as exit 47 northbound|
|48.02||77.28||47B||Bridge to Canada
|To Highway 3; southbound exit and northbound entrance; northern end of LECT concurrency|
Bridge to Canada
|Signed as exits 47C (left exit, Vernor Highway) and 47B (Ambassador Bridge) southbound|
|48.85||78.62||48||I-96 west (Jeffries Freeway) – Lansing||Eastern terminus of I-96|
|49.87||80.26||49||M-10 (Lodge Freeway) / Rosa Parks Boulevard – Civic Center||Signed as exits 49A (Rosa Parks Boulevard) and 49B (M-10) southbound|
|50.16||80.72||50||Grand River Avenue||Access to Comerica Park|
|50.82||81.79||51B||M-3 (Gratiot Avenue via Fisher Freeway) to M-53||Signed as exit 51 northbound|
|50.97||82.03||51C||I-375 south (Chrysler Freeway) – Downtown Detroit||One-lane ramps for I-75's transition between Fisher and Chrysler freeways; 25 mph (40 km/h) speed advisory|
|53.06||85.39||53B||I-94 (Ford Freeway) – Port Huron, Chicago|
|53.48||86.07||54||East Grand Boulevard, Clay Avenue|
|Hamtramck||55.14||88.74||55||Holbrook Avenue, Caniff Avenue|
|Detroit||56.17||90.40||56||M-8 (Davison Freeway)||Signed as exits 56A (east) and 56B (west)|
|58.02||93.37||58||7 Mile Road|
|Wayne–Oakland county line
||Detroit–Hazel Park city line||59.01||94.97||59||M-102 (8 Mile Road)|
||Hazel Park||60.11||96.74||60||John R. Road, 9 Mile Road|
Madison Heights–Royal Oak city quadripoint
|61.40||98.81||61||I-696 (Reuther Freeway) – Port Huron, Lansing|
|Royal Oak–Madison Heights city line||62.38||100.39||62||11 Mile Road, 10 Mile Road west|
|Madison Heights||63.38||102.00||63||12 Mile Road|
|Madison Heights–Troy city line||65.41||105.27||65||14 Mile Road||Signed as exits 65A (east) and 65B (west)|
|69.17||111.32||69||Big Beaver Road||Signed as exits 69A (east) and 69B (west)|
|72.28||116.32||72||Crooks Road||Indirect access to Crooks Road, requires exiting onto a trumpet interchange with Corporate Drive to reach Crooks Road|
|Bloomfield Township||74.31||119.59||74||Adams Road|
|75.64||121.73||75||BL I-75 north (Square Lake Road) – Pontiac||Signed as Square Lake Road southbound|
|Auburn Hills||77.58||124.85||77||M-59 – Utica, Pontiac||Signed as exits 77A (east) and 77B (west)|
|78.59||126.48||78||Chrysler Drive||Access to Featherstone Road|
|79.25||127.54||79||University Drive – Rochester|
|81.22||130.71||81||M-24 / BL I-75 south – Lapeer, Oxford||Access to The Palace of Auburn Hills|
|83.11||133.75||83||Joslyn Road||Signed as exits 83A (north) and 83B (south) southbound; east entrance to Great Lakes Crossing|
|84.34||135.73||84||Baldwin Road||Signed as exits 84A (north) and 84B (south) northbound; west entrance to Great Lakes Crossing|
|Independence Township||88.75||142.83||89||Sashabaw Road|
|90.99||146.43||91||M-15 – Clarkston, Davison|
|Springfield Township||92.79||149.33||93||US 24 (Dixie Highway) – Waterford||Northern terminus of US 24|
|98.21||158.05||98||East Holly Road|
|Groveland Township||101.19||162.85||101||Grange Hall Road – Fenton, Ortonville|
|Holly Township||106.33||171.12||106||Dixie Highway||Southbound exit and northbound entrance|
|106.63||171.60||106||Saginaw Road – Grand Blanc||Northbound exit and southbound entrance|
||Grand Blanc||108.86||175.19||108||Holly Road – Grand Blanc|
|110.08||177.16||109||M-54 north (Dort Highway) – Burton||Southern terminus of M-54|
|111.88||180.05||111||I-475 north – Downtown Flint||Northbound exit and southbound entrance|
|Mundy Township||115.12||185.27||115||US 23 south – Ann Arbor||Southern end of US 23 concurrency; southbound exit and northbound entrance|
|Flint||116.49||187.47||116||Bristol Road – Bishop International Airport||Signed as exits 116A (east) and 116B (west) southbound; former M-121|
|Flint Township||117.38||188.90||117||I-69 / Miller Road – Port Huron, Lansing||Signed as exits 117A (I-69) and 117B (Miller Road)|
|118.91||191.37||118||M-21 (Corunna Road) – Owosso|
|Mount Morris Township||122.11||196.52||122||Pierson Road – Flushing|
|125.59||202.12||125||I-475 south – Downtown Flint|
|Vienna Township||131.21||211.16||131||M-57 – Clio, Montrose|
||Birch Run||136.29||219.34||136||M-54 / M-83 – Birch Run, Frankenmuth||Northern terminus of M-54; southern terminus of M-83|
|Bridgeport Township||144.69||232.86||144||Frankenmuth, Bridgeport||Signed as exits 144A (Frankenmuth) and 144B (Bridgeport) northbound|
|Buena Vista Township||149.40||240.44||149||M-46 (Holland Avenue) – Sandusky||Signed as exits 149A (east) and 149B (west)|
|149.72||240.95||150||I-675 north – Downtown Saginaw|
|151.88||244.43||151||M-81 – Caro, Reese|
|153.08||246.36||153||M-13 (East Bay City Road) – Saginaw|
|Saginaw River||Zilwaukee Bridge|
|Zilwaukee Township||155.96||250.99||155||I-675 south – Downtown Saginaw|
||Frankenlust Township||160.30||257.98||160||M-84 (Saginaw Road)|
|Monitor Township||162.81||262.02||162|| US 10 west – Clare
M-25 east – Downtown Bay City
|Eastern terminus of US 10; western terminus of M-25 and the unsigned BL I-75; signed as exits 162A (east) and 162B (west)|
CONN M-13 – Kawkawlin
|Kawkawlin Township||168.05||270.45||168||Beaver Road|
|Fraser Township||173.01||278.43||173||Linwood Road – Linwood|
|Pinconning Township||181.02||291.32||181||Pinconning Road – Pinconning|
||Lincoln Township||188.65||303.60||188||US 23 north – Alpena, Standish||Northern end of US 23 concurrency|
|190.97||307.34||190||M-61 – Gladwin, Standish|
|Adams Township||195.08||313.95||195||Sterling Road – Sterling|
|Moffatt Township||202.87||326.49||202||M-33 north – Mio, Cheboygan|
||Horton Township||212.13||341.39||212||BL I-75 north (Cook Road) – West Branch|
|Ogemaw Township||215.73||347.18||215||M-55 east / BL I-75 south to M-30 – Tawas City, West Branch||Western end of M-55 concurrency|
||Richfield Township||222.83||358.61||222||Old 76 – St. Helen||Former M-76|
|Backus Township||227.60||366.29||227||M-55 west – Cadillac, Houghton Lake||Eastern end of M-55 concurrency|
|Higgins Township||239.61||385.61||239||M-18 / BL I-75 north – Roscommon, Houghton Lake|
|Gerrish Township||244.26||393.10||244||BL I-75 south – Roscommon, North Higgins Lake State Park|
||Beaver Creek Township||250.02||402.37||249||US 127 south – Lansing, Clare||Southbound exit and northbound entrance; northern terminus of US 127|
|Grayling Township||251.03||403.99||251||4 Mile Road|
|Grayling||254.11||408.95||254||BL I-75 north to M-72 – Downtown Grayling, Traverse City||Northbound exit and southbound entrance|
|256.14||412.22||256||North Down River Road||Southbound exit and northbound entrance|
|Grayling Township||259.19||417.13||259||M-93 (Hartwick Pines Road) / BL I-75 south to M-72 – Downtown Grayling, Traverse City||Signed as M-93 only (northbound)|
|Maple Forest Township||264.23||425.24||264||Frederic, Lewiston|
||Otsego Lake Township||270.83||435.86||270||Waters|
|Bagley Township||279.05||449.09||279||BL I-75 north (Old 27) – Downtown Gaylord||Former US 27; signed as Old 27 only (southbound)|
|Gaylord||281.95||453.75||282||M-32 / BL I-75 south – Downtown Gaylord, Alpena||Signed as M-32 only (northbound)|
|Vanderbilt||290.70||467.84||290||Old 27 – Vanderbilt|
||Nunda Township||300.97||484.36||301||C-58 – Wolverine|
|Indian River||310.16||499.15||310||M-68 – Indian River, Rogers City|
|313.49||504.51||313||M-27 north – Cheboygan, Indian River||Southern terminus of M-27|
|Munro Township||322.51||519.03||322||C-64 – Cheboygan, Pellston|
|Hebron Township||326.71||525.79||326||C-66 – Cheboygan, Cross Village|
|Mackinaw Township||335.69||540.24||336||US 31 south / LMCT south – Petoskey, Charlevoix||Southbound exit and northbound entrance; northern terminus of US 31 and southern end of LMCT concurrency|
|Cheboygan–Emmet county line
||Mackinaw–Wawatam township line||337.72||543.51||337||Nicolet Street north – Mackinaw City||Northbound exit and southbound entrance; southern terminus of the former M-108|
||Mackinaw City||338.47||544.71||338||US 23 south / LHCT south – Cheboygan, Rogers City, Alpena||Southbound exit and northbound entrance; northern terminus of US 23; southern end of LHCT, signed as the GLCT from here north|
|338||Michigan Welcome Center||Northbound exit only|
|Straits of Mackinac
||St. Ignace||343.80||553.29||343||Bridge View Park||Southbound exit only|
|344.38||554.23||344|| US 2 west / LMCT – Manistique, Escanaba
BL I-75 north / LHCT – St. Ignace
|Signed as exits 344A (north) and 344B (west) northbound; BL I-75 not signed southbound; eastern terminus of the western US segment of US 2; southern terminus of BL I-75; LMCT follows exit 344A to US 2 and LHCT follows exit 344B to BL I-75|
|345.08||555.35||345||Portage Street – St. Ignace||Southbound exit and northbound entrance|
|St. Ignace Township||348.10||560.21||348|| BL I-75 south / LMCT – St. Ignace
H-63 north / Mackinac Trail
|Signed as BL I-75 southbound and H-63 northbound; southern end of LMCT concurrency|
|352.15||566.73||352||M-123 north – Newberry||Southern terminus of M-123|
|359.37||578.35||359||M-134 east / LMCT – Drummond Island, De Tour Village||Western terminus of M-134; northern end of LMCT concurrency|
||Rudyard Township||373.71||601.43||373||M-48 east (H-40) – Pickford, Rudyard||Western terminus of M-48|
|Kinross Township||377.88||608.14||378||M-80 east – Kinross||Western terminus of M-80|
|379.64||610.97||379||Gaines Highway – Barbeau Area|
|Dafter Township||386.27||621.64||386||M-28 / LSCT west – Munising, Newberry||Southern end of LSCT concurrency|
|Sault Ste. Marie||392.57||631.78||392||BS I-75 north (3 Mile Road) / LMCT – Sault Ste. Marie||Southern end of LMCT concurrency signed as GLCT concurrency|
|394.74||635.27||394||Easterday Avenue – Sault Ste. Marie, Soo Locks|
|St. Marys River
||International Bridge to Canada|
Auxiliary routes 
There are four auxiliary Interstate Highways for I-75 in Michigan. I-275 begins as a loop from northern Monroe County and continues to connect with I-96 and I-696. The freeway serves the population of western Wayne County and Detroit Metropolitan Wayne County Airport. The highway was originally intended to connect with I-75 north of Pontiac. I-375 was the shortest signed Interstate in the nation;[e] It serves the immediate downtown Detroit area. I-475 is known as the UAW Freeway and the David Dunbar Buick Freeway. This freeway serves Flint's downtown areas as I-75 goes to the west side of the city. The fourth auxiliary Interstate is I-675, a loop into the city of Saginaw that served as an alternate to I-75 when the drawbridge over the Saginaw River was still operating.
In addition to the auxiliary Interstates, there are eight current business routes related to the freeway in the state. These business loops and spurs provide signed connections into the downtowns of Pontiac, Bay City, West Branch, Roscommon, Grayling, Gaylord, St. Ignace, and Sault Ste. Marie. A ninth highway was previously designated in Saginaw as well.
See also 
- The MBA is an independent state agency responsible for the Mackinac Bridge and thus maintains that section of the overall highway system. The MBA works with MDOT but does not report to it. The executive secretary of the MBA is appointed by MDOT with MBA approval.
- Northeast of Standish, M-10 ran along the Lake Huron shoreline.
- The Michigan State Highway Department was reorganized into the Michigan Department of State Highways and Transportation on August 23, 1973. The name was shortened to its current form in 1978.
- The Akashi Kaikyō and Great Belt bridges in the Eastern Hemisphere are each longer between anchorages at 12,826 feet (3,909 m) and 8,921 feet (2,719 m) respectively, but the Mackinac is still the longest between anchorages in the Western Hemisphere, and crosses a wider body of water.
- I-375 was the shortest signed Interstate Highway until I-110 was signed in 2010; I-878 and I-315 in New York City and Great Falls, Montana, are shorter, but unsigned.
- "Interstate 75 Road Markers Are Unveiled". The Herald-Press (St. Joseph, MI). Associated Press. October 13, 1959. p. 3. OCLC 10117184. Retrieved March 22, 2013.
- Staff (October 31, 2002). "Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Retrieved October 26, 2012.
- Meyer, Zlati (March 28, 2010). "You Haven't Lived Here Until You Drive I-75 Ohio to the Soo" (PDF). Detroit Free Press. p. 18A. Retrieved October 30, 2012.
- Michigan Department of Transportation (April 23, 2006) (PDF). National Highway System, Michigan (Map). http://www.michigan.gov/documents/MDOT_NHS_Statewide_150626_7.pdf. Retrieved October 7, 2008.
- Natzke, Stefan; Neathery, Mike; Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Federal Highway Administration. Retrieved July 1, 2012.
- Bureau of Transportation Planning (2012). "Traffic Monitoring Information System". Michigan Department of Transportation. Retrieved October 30, 2012.
- Michigan Department of Transportation (2012). State Transportation Map (Map). 1 in:15 mi / 1 cm:9 km. Section B11–G11, G11–M14, M14–N13, main map; section B8–E11, E11–H9, Detriot Area inset.
- Google Inc. Google Maps – Overview Map of I-75 in Michigan (Map). Cartography by Google, Inc. https://maps.google.com/maps?saddr=I-75+N&daddr=42.41798,-83.08751+to:Sault+Ste+Marie+International+Bridge&hl=en&sll=46.496915,-84.358006&sspn=0.056958,0.058279&geocode=FbTHfAIdLBAG-w%3BFTw_hwIdai8M-ylN2vRw_M0kiDFiEnNGSZxgpQ%3BFaypxQId-sH4-g&oq=Sault&mra=ls&via=1&t=h&z=7. Retrieved October 27, 2012.
- Oosting, Jonathan (December 5, 2010). "Worst Freeway for Accidents in Metro Detroit? Stretch of I-75 Where Tanker Exploded Last Year". MLive (Detroit: Booth Newspapers). Retrieved October 29, 2012.
- Ranzenberger, Mark (April 27, 2008). "US 127 Signs Getting Updated". The Morning Sun (Mount Pleasant, MI). pp. 1A, 6A. OCLC 22378715. Retrieved August 23, 2012.
- Barnett, p. 88.
- "Bridge Legislation Signed". The Grand Rapids Press. Associated Press. December 29, 2005. p. B3.
- Gould, Karen (July 26, 2007). "A Day in the Life of the Mackinac Bridge". The St. Ignace News. Retrieved April 5, 2013.
- "Mackinac Bridge Toll Increase". Negaunee, MI: WLUC-TV. Associated Press. December 30, 2011. Retrieved April 5, 2013.
- Greenwood, Tom (April 18, 2009). "'Quick Card' payment to be used at Mackinac Bridge". The Detroit News. p. 3A. Retrieved April 5, 2013.(subscription required)
- Schneider, Kim (May 20, 2007). "Fear the Mighty Mac? They get you over it". MLive (Booth Newspapers). Retrieved April 5, 2013.
- Carr, Tom (July 1, 2007). "Troubled Over Bridged Waters: Mackinac Crew Offers Rides to Those with Severe Phobia". Traverse City Record-Eagle. pp. 1E, 2E. Retrieved April 5, 2013.
- "WNHC787 AM 530 St. Ignace / AM 1610 Mackinaw City". MichiGuide. Retrieved April 5, 2013.
- Michigan State Highway Department (1963). Official Highway Map (Map). Section B11–D11, F10, K12–L13.
- Michigan State Highway Department (1964). Official Highway Map (Map). Section B11–D11, L13.
- Rand McNally (2013). The Road Atlas (Map) (2013 Walmart ed.). p. 50, section E8–F8. ISBN 0-528-00626-6.
- International Bridge Authority (October 1, 2012). "Currency Equity Toll Adjustment". Michigan Department of Transportation. Retrieved April 5, 2013.
- International Bridge Authority. "The IQ Prox Card (Automated Transactions)". Michigan Department of Transportation. Retrieved April 5, 2013.
- Morrison, p. 1.
- Mason, p. 18.
- Morrison, pp. 7–8.
- Mason, p. 4.
- Michigan Legislature, p. 1868
- "Michigan May Do Well Following Wisconsin's Road Marking System". The Grand Rapids Press. September 20, 1919. p. 10. OCLC 9975013.
- Michigan State Highway Department (July 1, 1919). State of Michigan: Lower Peninsula (Map). Cartography by MSHD.
- Michigan State Highway Department (July 1, 1919). State of Michigan: Upper Peninsula (Map). Cartography by MSHD.
- Bureau of Public Roads (November 11, 1926) (PDF). United States System of Highways (Map). OCLC 32889555. http://www.okladot.state.ok.us/hqdiv/p-r-div/maps/misc-maps/1926us.pdf. Retrieved May 10, 2008.
- Kulsea, p. 27.
- Kulsea, pp. 30–1.
- Michigan State Highway Department (May 1, 1933). Official Michigan Highway Map (Map). Cartography by Rand McNally.
- Michigan State Highway Department (September 1, 1933). Official Michigan Highway Map (Map). Cartography by Rand McNally.
- Michigan State Highway Department (October 1, 1945). Official Highway Map of Michigan (Map). Section N13.
- Public Roads Administration (August 2, 1947). National System of Interstate Highways (Map). http://commons.wikimedia.org/wiki/File:Interstate_Highway_plan_August_2,_1947_big_text.jpg. Retrieved September 4, 2010.
- Bureau of Public Roads (September 1955). General Location of National System of Interstate Highways Including All Additional Routes at Urban Areas Designated in September 1955 (Yellow Book) (Map). OCLC 4165975. http://commons.wikimedia.org/wiki/File:Interstate_Highway_plan_September_1955.jpg. Retrieved September 4, 2010.
- Staff (March 1, 2010) (PDF). Section 394 Report: Analysis of Transportation Funding Distribution Formula (Report). Michigan Department of Transportation. p. 12. http://www.micountyroads.org/PDF/Sec_394_Report_2010.pdf. Retrieved October 28, 2012.
- "Michigan To Push Its North–South Turnpike: Toll Road To Link Centers of Industrial Areas". Youngstown Vindicator. February 21, 1955. p. 2. OCLC 5424159. Retrieved October 30, 2012.
- "Michigan Turnpike Law Upheld". The Milwaukee Sentinel. December 2, 1955. p. B2. ISSN 1052-4479. Retrieved October 30, 2012.
- Coverdale and Colpitts (1955). Report on Estimated Traffic and Earnings of the Proposed Michigan Turnpike, Project No 1, North-South Turnpike (Report). New York: Michigan Turnpike Authority. p. 2. OCLC 35260166. http://babel.hathitrust.org/cgi/pt?id=mdp.39015024498522;seq=26;view=1up;num=2. Retrieved October 30, 2012.
- Richard, Tim (April 3, 1986). "I-275: The Interstate that Isn't". Livonia Observer. OCLC 22646576.
- Bagley, Les (October 25, 2007). "Autos Across Mackinac: Michigan Decides Against Building Turnpikes". The St. Ignace News. OCLC 36250796. Retrieved October 30, 2012.
- "Cross-State 'Pike Planned". Traverse City Record-Eagle. December 14, 1955. p. 16. OCLC 30098364. Retrieved October 31, 2012.
- "Michgian Drops Detroit–Chicago Turnpike Plans: Mackinac Extension of Saginaw Toll Road Also Abandoned". Toledo Blade. April 18, 1956. p. 5. Retrieved October 31, 2012.
- "World News Summary". Ludington Daily News. Associated Press. May 25, 1957. p. 1. OCLC 27033604. Retrieved October 31, 2012.
- Bagley, Les (January 17, 2008). "Autos Across Mackinac: Bridge Construction Continues; Tourism Down". The St. Ignace News. OCLC 36250796. Retrieved October 30, 2012.
- "See Scant Chance for Highway". Ludington Daily News. August 21, 1956. p. 1. OCLC 27033604. Retrieved October 31, 2012.
- "Legislature Moves To Kill 15 Obsolete Laws". The Owosso Argus-Press. February 28, 1962 . p. 16. Retrieved October 31, 2012.
- "Ohio, Michigan Dedicate New Expressway". Chicago Daily Tribune. May 23, 1959. p. 3. OCLC 1554151.
- Kulsea, p. 22.
- Staff (April 25, 1958). "Recommended Interstate Route Numbering for Michigan". Michigan State Highway Department. Archived from the original on August 5, 2004. Retrieved September 4, 2010.
- "Fenton–Clio X-Way Big Time Saver". Argus-Press (Owosso, MI). Associated Press. June 28, 1958. p. 9. OCLC 36134862. Retrieved April 20, 2011.
- Michigan State Highway Department (1960). Official Highway Map (Map). Section C10–E10, J12–L12. (Includes all changes through July 1, 1960)
- Barnett, p. 233.
- "Michigan Delays Road Number System". Toledo Blade. Associated Press. June 4, 1959. p. 11. Retrieved November 21, 2010.
- "Michigan To Open 35 More Miles of Freeway". The Blade (Toledo, OH). Associated Press. November 8, 1960. p. 19. Retrieved March 22, 2013.
- "122 Miles of Freeway To Be Opened by Dec. 15". The Herald-Press (St. Joseph, MI). October 17, 1960. OCLC 10117184. Retrieved March 23, 2013.
- "Michigan Town Wants Used Bridge". Wilmington Morning Star. Associated Press. December 11, 1979. p. 3D. ISSN 0163-402X. Retrieved March 22, 2013.
- Michigan State Highway Department (1961). Official Highway Map (Map). Section C10–G10, J12–K12. (Includes all changes through July 1, 1961)
- "Bypasses Gaylord". The Herald-Press (St. Joseph, MI). Associated Press. September 1, 1962. p. 2. OCLC 10117184. Retrieved March 23, 2013.
- "75 Opened". Ludington Daily News. Associated Press. October 9, 1961. p. 8. OCLC 27033604. Retrieved March 23, 2013.
- "Upper Peninsula To Get Many Highway Projects Next Year". Ironwood Daily Globe. December 22, 1961. p. 8. OCLC 10890811. Retrieved March 23, 2013.
- Michigan State Highway Department (1962). Official Highway Map (Map). Section C11, F10–G10, G10–J12, K12–L13.
- "State Briefs". Argus-Press (Owosso, MI). July 7, 1962. p. 4. OCLC 36134862.
- "New Section of I-75 Opens". The News-Palladium (Benton Harbor, MI). Associated Press. October 26, 1962. Section 2, p. 19. Retrieved March 23, 2013.
- Staff (September 12, 2008). "Facts & Trivia". International Bridge. Michigan Department of Transportation. Retrieved October 26, 2012.
- "Completes Hike". Traverse City Record-Eagle. United Press International. October 31, 1963. p. 6. OCLC 30098364. Retrieved March 23, 2013.
- White, Elmer E. (November 1, 1963). "Michigan Mirror: Nation's Nicest". Ludington Daily News. p. 4. OCLC 27033604. Retrieved March 23, 2013.
- Mackie, John C. (December 26, 1963). "John Mackie Lists Many Achievements for 1963". Holland Evening Sentinel. United Press International. p. 22. OCLC 13440201. Retrieved March 23, 2013.
- Michigan State Highway Department (1965). Official Highway Map (Map). Section M13.
- Michigan Department of State Highways (1966). Official Highway Map (Map). Section M13.
- Michigan Department of State Highways (1967). Official Highway Map (Map). Section I12–J12, M13.
- Michigan Department of State Highways (1968). Official Highway Map (Map). Section I12–J12, M13.
- Michigan Department of State Highways (1969). Official Highway Map (Map). 1 in:14.5 mi. Cartography by H.M. Gousha. Section I12, M13.
- Michigan Department of State Highways (1970). Official Highway Map (Map). 1 in:14.5 mi. Section G11, H12–I12, M13.
- Michigan Department of State Highways (1971). Official Highway Map (Map). 1 in:14.5 mi. Section G11, H12–I12, M13.
- White, Elmer E. (December 15, 1970). "Michigan Mirror: Detection System Started". Ludington Daily News. p. 4. OCLC 27033604. Retrieved March 23, 2013.
- "I-75 Complete Inside Michigan". The News-Palladium (Benton Harbor). Associated Press. December 6, 1971. p. 33. Retrieved March 23, 2013.
- Michigan Department of State Highways (1972). Official Highway Map (Map). 1 in:14.5 mi. Section H12, M13.
- "Around the State: West Branch". Traverse City Record-Eagle. United Press International. November 2, 1973. p. 3. OCLC 30098364. Retrieved March 23, 2013.
- Michigan Department of State Highways (1973). Official Highway Map (Map). 1 in:14.5 mi. Section H12.
- Michigan Department of State Highways and Transportation (1974). Official Highway Map (Map). 1 in:14.5 mi. Section H12.
- Michigan Department of Transportation (1983). Official Transportation Map (Map). 1 in:14.5 mi./1 in:23 km. Section C10–C11.
- Michigan Department of Transportation (1943). Official Transportation Map (Map). 1 in:14.5 mi./1 in:23 km. Section C10–C11.
- Michigan Department of Transportation (1986). Official Transportation Map (Map). 1 in:14.5 mi / 1 in:23 km. Section J12–L13.
- Michigan Department of Transportation (1987). Official Transportation Map (Map). 1 in:14.5 mi / 1 in:23 km. Section J12–L13.
- Staff Writer (September 19, 1988). "Zilwaukee Bridge Now Open North, South—Partly". The Blade (Toledo, OH). p. 1. Retrieved October 29, 2012.
- "Motorists Maneuver Through Gateway Project Maze". The Detroit News. February 26, 2008. pp. 1B, 5B. Retrieved October 29, 2012.
- Greenwood, Tom (June 27, 2009). "I-75 To Open for Traffic Next Week at Gateway Project". The Detroit News. p. 3A. Retrieved October 29, 2012.
- Helms, Matt; Gallagher, John (January 12, 2012). "Mich. Billionaire, 84, Jailed over Bridge Dispute". USA Today. Retrieved October 29, 2012.
- Wattrick, Jeff T. (March 16, 2012). "MDOT Launches 'Getting Gateway to the Finish Line' Social Campaign". MLive (Detroit: Booth Newspapers). Retrieved October 29, 2012.
- Muller, David (September 20, 2012). "Detroit Neighborhoods To See Less Truck Traffic as $230 million Gateway Plaza Opens". MLive (Detroit: Booth Newspapers). Retrieved October 29, 2012.
- Board of Wayne County Road Commissioners (1960). Route Location Study: FAI 75: Detroit–Toledo Expressway to Rouge River (Report). Michigan State Highway Department. OCLC 23314996.
- Barnett, pp. 81–2.
- Barnett, pp. 22–3.
- Barnett, pp. 178–8.
- Hyde, p. 166.
- Hyde, p. 168.
- United States nominal Gross Domestic Product per capita figures follow the "Measuring Worth" series supplied in Lawrence H. Officer (2011), "What Was the U.S. GDP Then?" MeasuringWorth. These figures follow the figures as of November 2011.
- Staff (December 10, 2007). "1980s". History & Culture. Michigan Department of Transportation. Retrieved October 29, 2012.
- Hyde, pp. 159–66.
- Rubin, pp. 13–7.
- Rubin, pp. 103–7.
- Staff. "About the Bridge". Mackinac Bridge Authority. Retrieved October 28, 2012.
- Staff. "Mackinac Bridge". American Society of Civil Engineers. Retrieved October 29, 2012.
- Google Inc. Google Maps – Interchange between Fisher and Chrysler Freeways, Detroit (Map). Cartography by Google, Inc. https://maps.google.com/maps?q=detroit&hl=en&ll=42.342131,-83.045086&spn=0.007645,0.007521&sll=40.365277,-82.669252&sspn=8.067848,7.701416&hnear=Detroit,+Wayne,+Michigan&t=h&z=17. Retrieved April 5, 2013.
- Metro Region. Northbound I-75 Advisory Sign (Highway sign). Detroit: Michigan Department of Transportation. http://www.flickr.com/photos/tenpoundhammer/5842925221/. Retrieved April 5, 2013.
- Staff (2010). Northbound I-110/US 54/I-10/US 180 Pull-Through Sign (Highway guide sign). El Paso, TX: Texas Department of Transportation. http://commons.wikimedia.org/wiki/File:Interstate-110-El-Paso.jpg. Retrieved October 27, 2012.
- Staff (October 31, 2002). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Retrieved March 25, 2010.
- Rand McNally (2009). The Road Atlas (Map). Section N16, Great Falls inset, p. 61; Section J13–14, New York City & Vicinity inset, p. 73; Section WT3, El Paso inset, p.99. ISBN 0-528-93981-5.
- Barnett, pp. 40–1, 215.
Works cited 
- Barnett, LeRoy (2004). A Drive Down Memory Lane: The Named State and Federal Highways of Michigan. Allegan Forest, MI: The Priscilla Press. ISBN 1-886167-24-9.
- Hyde, Charles K. (1993). Historic Highway Bridges of Michigan. Detroit: Wayne State University Press. ISBN 0-8143-2448-7.
- Kulsea, Bill; Shawver, Tom (1980). Making Michigan Move: A History of Michigan Highways and the Michigan Department of Transportation. Lansing, MI: Michigan Department of Transportation. OCLC 8169232.
- Mason, Philip P. (1959). Michigan Highways From Indian Trails to Expressways. Ann Arbor, MI: Braun-Brumfield. OCLC 23314983.
- Michigan Legislature (1915). "Chapter 91: State Reward Trunk Line Highways". In Shields, Edmund C.; Black, Cyrenius P.; Broomfield, Archibald. The Compiled Laws of the State of Michigan, Volume I. Lansing, MI: Wynkoop, Hallenbeck, Crawford. pp. 1868–72. OCLC 44724558. Retrieved January 24, 2012.
- Morrison, Roger L. (Autumn 1937). "The History and Development of Michigan Highways". Michigan Alumnus Quarterly Review (Ann Arbor, MI: University of Michigan Bureau of Alumni Relations) 39 (54): 59–73. OCLC 698029175.
- Rubin, Lawrence A. (1985). Bridging the Straits. Detroit: Wayne State University Press. ISBN 0-8143-1789-8.
|Wikimedia Commons has media related to: I-75 in Michigan|