Interstate 96 (I-96) is an east–west Interstate Highway that runs for approximately 192 miles (309 km) entirely within the Lower Peninsula of the US state of Michigan. The western terminus is at an interchange with US Highway 31 (US 31) and Business US 31 on the eastern boundary of Norton Shores southeast of Muskegon, and the eastern terminus is at I-75 near the Ambassador Bridge in Detroit. From Grand Rapids through Lansing to Detroit, the freeway parallels Grand River Avenue, never straying more than a few miles from the decommissioned US 16. The Wayne County section of I-96 is named the Jeffries Freeway from its eastern terminus to the junction with I-275 and M-14. Though maps still refer to the freeway as the Jeffries, the portion within the city of Detroit was renamed by the state legislature as the Rosa Parks Memorial Highway in December 2005 in honor of the late civil rights pioneer. There are four auxiliary Interstates as well as two current and four former business routes associated with I-96.
M-37 is a north–south state trunkline highway in the US state of Michigan. The southern terminus is near the border between Kalamazoo and Calhoun counties at exit 92 of Interstate 94 (I-94) southwest of Battle Creek. The northern terminus is at the Mission Point Light on Old Mission Point in Grand Traverse County. In between, the highway connects Battle Creek, Grand Rapids and Traverse City. Motorists will travel through agricultural land, forests, suburbs and large cities along the way. The section of M-37 on the Old Mission Peninsula was designated what is now a Pure Michigan Scenic Byway in 2008.
M-78 is a state trunkline highway in the US state of Michigan. The western terminus is the intersection with M-66 north of Battle Creek in Pennfield Township. The roadway runs 10.744 miles (17.291 km) through rural farmland and the community of Bellevue as it approaches its eastern terminus at an interchange with Interstate 69 (I-69) near Olivet. The highway is used by between 3,100 and 5,300 vehicles on a daily basis.
M-21 is an east–west state trunkline highway in the US state of Michigan connecting the cities of Grand Rapids and Flint. The highway passes through rural farming country and several small towns along its course through the Lower Peninsula. Following the course of a handful of rivers, M-21 also connects some of the state's freeways like Interstate 96 (I-96), US Highway 127 (US 127) and I-75. The highway is used by between 1,700 and 36,000 vehicles daily.
Interstate 196 (I-196) is an auxiliary Interstate Highway that runs for 80.6 miles (129.7 km) in the US state of Michigan. It is a state trunkline highway that links Benton Harbor, South Haven, Holland, and Grand Rapids. In Kent, Ottawa, and Allegan counties, I-196 is known as the Gerald R. Ford Freeway, or simply the Ford Freeway, after President Gerald Ford, who was raised in Grand Rapids and served Michigan in the House of Representatives for 25 years. This name generally refers only to the section between Holland and Grand Rapids. I-196 changes direction; it is signed as a north–south highway from its southern terminus to the junction with US Highway 31 (US 31) just south of Holland, and as an east–west trunkline from this point to its eastern terminus at an interchange with I-96, its parent highway. There are three business routes related to the main freeway. There are two business loops and one business spur that serve South Haven, Holland and the Grand Rapids areas. Another business spur for Muskegon had been designated relative to the I-196 number.
M-43 is a state trunkline highway in the southwestern and central parts of the US state of Michigan. The highway runs from South Haven to Webberville along an indirect path through both rural areas and larger cities. The trunkline follows five overall segments: a southeasterly track from South Haven to Oshtemo Township, a northerly path to Plainwell, a southeasterly route to Richland, a northeasterly course to the Hastings area and an easterly route through the Lansing area.
US Highway 16 (US 16), also called Grand River Avenue for much of its length in the state, was one of the principal roads prior to the post-World War II construction of freeways in the state of Michigan. Before the creation of the United States Numbered Highway System in 1926, the highway had been designated as a state highway numbered M-16. The modern route of Grand River Avenue cuts across the Lower Peninsula in a northwest–southeast fashion from near Grand Rapids to Detroit. Before the late 1950s and early 1960s, US 16 followed other roads between Muskegon and Grand Rapids, and then Grand River Avenue through Lansing to Detroit. In the years immediately preceding the creation of the Interstate Highway System, US 16 was shifted from older roads to newer freeways. Later, it was co-designated as an Interstate. When the gap in the freeway was filled in around Lansing, the US 16 designation was decommissioned in the state. The freeway was solely designated Interstate 96 (I-96) east of Grand Rapids and I-196 west of that city.
M-50 is a state trunkline highway in the US state of Michigan. Although designated as an east–west highway, it is nearly a diagonal northwest–southeast route. The western terminus is at exit 52 along Interstate 96 (I-96) near Alto a few miles east of the metro Grand Rapids area, and its eastern terminus is in downtown Monroe at US Highway 24. In between the trunkline runs through seven counties of the southern part of the Lower Peninsula mostly through rural farm fields and small communities. The highway also runs through downtown Jackson to connect between two freeway sections of US 127. In the Irish Hills area of the state southeast of Jackson, M-50 runs next to Michigan International Speedway.
M-6, or the Paul B. Henry Freeway, is a 19.7-mile-long (31.7 km) east–west freeway and state trunkline highway in the United States that serves portions of southern Kent and eastern Ottawa counties south of Grand Rapids, Michigan. Although the freeway is named for Paul B. Henry, local residents and the press continue to use the original name, South Beltline as well on occasion. The freeway connects Interstate 196 (I-196) on the west with I-96 on the east. M-6 also provides a connection to U.S. Highway 131 (US 131) in the middle of its corridor while running through several townships on the south side of the Grand Rapids metropolitan area in Western Michigan. Each end is in a rural area while the central section has suburban development along the trunkline.
M-17 is a 6.390-mile-long (10.284 km) state trunkline highway in the U.S. state of Michigan, connecting the cities of Ypsilanti and Ann Arbor in Washtenaw County. It was once part of a highway that spanned the southern Lower Peninsula of Michigan before the creation of the U.S. Highway System in 1926. The designation once extended into downtown Detroit, but the eastern terminus was progressively scaled back in the late 1960s to the current location in Ypsilanti. The changes made to the highways in Washtenaw County spawned Business M-17, a business loop for 11 years between 1945 and 1956.
M-11 is a state trunkline highway in the US state of Michigan in the Grand Rapids metropolitan area. The highway runs through the western and southern sides of the metro area, starting over the border in Ottawa County at an interchange with Interstate 96 (I-96). It runs through both rural woodlands and busy commercial areas before it terminates at another interchange with I-96 in Cascade Township. Locally known as Wilson Avenue and 28th Street, the trunkline is listed on the National Highway System. M-11 carries between 8,000 and 42,000 vehicles on average each day.
M-58 is a 5.108-mile-long (8.221 km) east–west state trunkline highway in the US state of Michigan that runs from M-47 in Saginaw Township east to exit 3 of Interstate 675 (I-675) near the north part of downtown Saginaw. The trunkline follows State Street through the Saginaw area, and east of Lathrop Avenue, M-58 is split along two streets, using Davenport Avenue as well. This is the third time that the number has been used on a highway in Michigan; the first two were used in the Berrien County and Pontiac areas. The Saginaw version was designated in 1971, and it is listed on the National Highway System.
M-45 is a state trunkline highway in the US state of Michigan that is also called Lake Michigan Drive. The highway runs from Agnew near Lake Michigan to the west side of Grand Rapids in the western Lower Peninsula. Lake Michigan Drive continues in each direction from M-45's termini, extending west of US Highway 31 (US 31) and east of Interstate 196 (I-196). In between, the road runs through rural and suburban areas of Ottawa and Kent counties, including the main campus of Grand Valley State University in Allendale. Lake Michigan Drive was originally part of M-50 until the mid-1960s. Previously in the 1920s and 1930s, the M-45 number was designated along a highway in the Upper Peninsula (UP).
M-39 is a 16-mile-long (26 km) north–south state trunkline highway in Metro Detroit area of the US state of Michigan that runs from Lincoln Park, on the south end, to Southfield on the north. The official southern terminus of M-39 is at the corner of Southfield Road and Lafayette Boulevard in Lincoln Park, one block southeast of the junction of Interstate 75 and two blocks northwest of M-85. From there the highway heads northward. The first 2.3 miles (3.7 km) of the highway follows Southfield Road, a divided highway in the Downriver area. It then transitions into the Southfield Freeway, which is a 13.7-mile-long (22.0 km) freeway that runs from I-94 in Allen Park north through Dearborn, and then the west side of Detroit, to Southfield. The northern terminus is at M-10 in Southfield.
M-85, also known as Fort Street or Fort Road for its entire length, is a state trunkline highway in the U.S. state of Michigan. The highway serves several Downriver suburbs of Detroit, as well as neighborhoods in the city itself. From its southern terminus at exit 28 on Interstate 75 (I-75) to its second interchange with exit 43 on I-75 in southwest Detroit, M-85 is part of the Lake Erie Circle Tour. In between, it serves mostly residential areas running parallel to a pair of rail lines; the highway carries between 5,000 and 43,000 vehicles per day on average. Once in the city of Detroit, Fort Street runs parallel to I-75 for several miles before they separate near the Ambassador Bridge. The northern end of M-85 is at the intersection with Griswold Street in downtown Detroit, one block away from Campus Martius Park.
US Highway 131 (US 131) is a north–south United States Highway, of which all but 0.64 of its 269.96 miles are within the state of Michigan. The highway starts in rural Indiana south of the state line as a state road connection to the Indiana Toll Road. As the road crosses into Michigan it becomes a state trunkline highway that connects to the metropolitan areas of Kalamazoo and Grand Rapids before continuing north to its terminus at Petoskey. US 131 runs as a freeway from south of Portage through to Manton in the north. Part of this freeway runs concurrently with Interstate 296 (I-296) as an unsigned designation through Grand Rapids. US 131 forms an important corridor along the western side of the Lower Peninsula of Michigan, running through rural farm and forest lands as well as urban cityscapes. Various names have been applied to the roadway over the years. The oldest, the Mackinaw Trail, originated from an Indian trail in the area while other names honored politicians. An attempt to dedicate the highway to poet James Whitcomb Riley failed to gain official support in Michigan.
M-44 is a 37.463-mile (60.291 km) state trunkline highway in the western region of the US state of Michigan. It runs northward from the intersection of M-11 and M-37 toward the Rockford area. The highway then turns eastward to Belding, and it ends six miles (10 km) north of Ionia at M-66. M-44 is known in Grand Rapids as the "East Beltline" and intersects with its related highway, Connector M-44, in Plainfield Township. This highway runs concurrently with M-37 between M-11 and Interstate 96 (I-96).
US Highway 12 (US 12) is an east–west United States Numbered Highway that runs from Aberdeen, Washington, to Detroit, Michigan. In Michigan, it runs for 210 miles (340 km) between New Buffalo and Detroit as a state trunkline highway and Pure Michigan Byway. On its western end, the highway is mostly a two-lane road that runs through the southern tier of counties roughly parallel to the Indiana state line. It forms part of the Niles Bypass, a four-lane expressway south of Niles in the southwestern part of the state, and it runs concurrently with the Interstate 94 (I-94) freeway around the south side of Ypsilanti in southeastern Michigan. In between Coldwater and the Ann Arbor area, the highway angles northeasterly and passes Michigan International Speedway. East of Ypsilanti, US 12 follows a divided highway routing on Michigan Avenue into Detroit, where it terminates at an intersection with Cass Avenue.
There are six business routes of US Highway 131 in the state of Michigan, and previously there was one bypass route and an additional business route. All of the business routes are former sections of US Highway 131 (US 131). These former sections of the mainline highway, along with the necessary connecting roads, allow traffic to access the downtowns business districts of cities bypassed by sections of US 131 built since the 1950s. The extant business loops connect to Constantine, Three Rivers, Kalamazoo, Big Rapids, Cadillac, and Manton. The former bypass route in Grand Rapids allowed traffic to bypass that city's downtown at a time when US 131 still ran through the heart of the city, and the later business route connected through downtown while US 131 ran on a freeway bypassing the central business district.
Byp. US 16 in Paris Township 
US 131 near Comstock Park
