Michigan Road Network

By | October 13, 2022

The Blue Water Bridge on the Canadian border at Port Huron.

The state has an extensive road network. The population is mainly concentrated in the south, which is also where most of the highways are located. Southern Michigan has a grid pattern, the center and north are forested and have a thinner road network. In the Upper Peninsula in particular, the road network is thinner than in the Lower Peninsula. Known are the ‘X Mile Road’ from Detroit to the north.

Road management

The state highway authority is the Michigan Department of Transportation, abbreviated MDOT. MDOT manages 15,557 kilometers of roads and 4,755 bridges. The state operates 1,995 kilometers of Interstate Highway and 3,128 kilometers of freeway (including the Interstates). The road network in the state management is also referred to as the ‘state trunkline system’. Although this is only 8 percent of Michigan’s road network, it accounts for 53% of all vehicle miles and 66% of all tonne-miles. In total, Michigan has over 196,000 kilometers of road, the eighth largest road network in the United States. However, most roads are under the control of the counties and municipalities. The state highway system is only the 27th largest in the United States, indicating a relatively high degree of decentralized road management.

MDOT has its origins in the Michigan State Highway Department that was established in 1905. Michigan was one of the first states to have a separate ministry for roads, since in many states at the time this often only came under a committee and a separate ministry was not established until the 10’s of the 20th century. In 1913, the state trunkline highway system was created, which was signposted from 1919. Michigan was the second state to sign road numbers. In 1973, the Department was renamed the Michigan Department of State Highways and Transportation, which was later abbreviated to the Michigan Department of Transportation. At the time, many states wanted to emphasize that transportation was more than just roads, although in practice roads played by far the most important role in transportation in the states.

  • Bittranslators: State overview of Michigan, including geography, economy, population and history as well as introduction to major cities of Michigan.

Interstate Highways

Michigan’s highway network.

Michigan is slightly eccentric from the U.S. highway system because of the Great Lakes, so fewer main routes of the Interstate Highway system pass through Michigan than in surrounding states. Interstate 69 hooks through the state, running first north-south to Lansing and later east-west to the border with Canada at Port Huron. Interstate 75 is the main north-south route, spanning over 600 kilometers across the state via Detroit, Flint, and Saginaw to the Canadian border at Sault Ste. Mary. The Mackinac Bridge of I-75 is the only road link between the Lower Peninsula and the Upper Peninsula. The Interstate 94 is a major east-west route connecting Chicago to Detroit, and several regional towns in between. I-94 continues on to the Canadian border at Port Huron, where it reaches I-69. Interstate 96 is an “intrastate” route because it only runs in Michigan and runs from Muskegon through Grand Rapids and Lansing to Detroit.

The state has a larger number of auxiliary routes because of the many cities. Interstate 194 is a short spur of I-94 at Battle Creek, and Interstate 196 is an inter-regional connection between St. Joseph and Grapd Rapids, via Holland. Interstate 275 forms the western bypass of the Detroit metropolitan area. Interstate 296 is an unsigned Interstate Highway in Grand Rapids. Interstate 375 is a short spur from I-75 in downtown Detroit. Interstate 475 forms the bypass of Flint and Interstate 496 is an east-west route through the state capital Lansing. The Interstate 675 is a route through the city of Saginaw that begins and ends on I-75 and Interstate 696 forms Detroit’s northern bypass. I-275 and I-696 collectively form a hook around the city.

Many freeways in Detroit have famous names, such as the Chrysler Freeway (I-75), Fisher Freeway (I-75), Detroit Industrial Freeway (I-94), Edsel Ford Freeway (I-94), Jeffries Freeway (I-96 ) and Reuther Freeway (I-696).

  • Deluxesurveillance: Nickname of Michigan as The Great Lakes State. Also covers geography, history, economy, politics and administration of the state.

US Highways

For a state with such a population, early industrialization, and geographic size, there are also relatively few US Highways running through Michigan. US 2 is the primary east-west link through the Upper Peninsula. US 10 forms an east-west route through the center of the state and is a freeway between Clare and Bay City. US 12 forms an east-west route through the south of the state and is somewhat more secondary in character. The U.S. 23 is one of the major north-south routes, it has been extended as a freeway over a long stretch from Toledo to Flint, as a regional bypass of Detroit, via Ann Arbor. Further north, US 23 follows the shoreline of Lake Huron and is a major tourist route. US 24 is a secondary route, but it follows the famous ‘Telegraph Road’ through the Detroit area.

US 31 is the main north-south route through the west of the state and has been developed as a freeway between the Indiana and St. Joseph borders and from Grand Haven to Ludington. US 31 has a notorious missing link a few miles near Benton Harbor, where the freeway just falls short of I-94. US 41 and US 45 form north-south routes across the Upper Peninsula.

US 127 is a major north-south route through the middle of the state and has been largely developed as a freeway, primarily from Jackson via Lansing to Grayling. US 131 is a north-south route through the west of the state, more inland from Lake Michigan. A long stretch of US 131 is a freeway, from Portage through Kalamazoo, Grand Rapids and Cadillac to Manton. US 127 and US 131 are Michigan’s longest non-interstate freeways. US 141 forms a north-south route across the Upper Peninsula and US 223 is a somewhat secondary east-west route in the southeast of the state.

State Highways

The network of roads in the state’s administration is referred to as the “Michigan State Trunkline Highway System.” The state highways are abbreviated as ‘M-XX’, one of the few states where such abbreviation is used. This usage has its origins in the first numbering from 1919. The road numbers are one, two or three digits, with relatively few numbers higher than 250. There is no clear numbering system in Michigan, although lower numbers are mainly in major cities.

Unlike some states, state highway numbers may also appear as US Highways and Interstate Highways. Many states skip these numbers, but not Michigan. The numbers of some M roads are even derived or predecessors of US Highways.

Some state highways are designed as freeways, especially in the major conurbations. The best known are;

  • M-5 (Grand River Avenue) in Detroit
  • M-6 along the south side of Grand Rapids
  • M-8 (Davison Expressway) in Detroit and Highland Park
  • M-10 (Lodge Freeway) in Detroit
  • M-14 between Ann Arbor and Livonia
  • M-39 (Southfield Freeway) in Detroit
  • M-53 north of Detroit
  • M-59 between Pontiac and Sterling Heights

Toll roads

The Mackinac Bridge ( I-75 ).

There are no general toll roads in Michigan. A number of bridges do require tolls, the only one located entirely in Michigan is the Mackinac Bridge between the Lower and Upper Peninsula, part of I-75. In addition, there are four additional toll connections to Canada, the Ambassador Bridge in Detroit, the Detroit-Windsor Tunnel, and the Blue Water Bridge at Port Huron, as well as the Sault Ste. Marie International Bridge in northern Michigan, at the terminus of I-75.

Toll roads have been considered in the past, the Michigan Turnpike Authority was established in 1951, following the lead of Illinois, Indiana and Ohio. However, the construction of a toll road never got off the ground and toll roads became redundant after the creation of the Interstate Highway system in 1956.


The roads of the 19th century were the so-called ‘Indian Trails’, actually trails for horses. Most of these started in Detroit and went to other parts of Michigan. From 1805 farm-to-market roads were built to open up agricultural areas. These were dirt roads that divided the country into a grid. In the early 1800s, Detroit also began developing wide boulevards. The first gravel roads were developed in the countryside from the middle of the 19th century. In addition, so-called ‘plank roads’ were developed, roads with wooden pavement. These were often classic turnpikes on which tolls were levied. One problem with plank roads was that the wood started to rot after some time.

In 1905, the Michigan State Highway Department was established. At the time, there was 110,000 miles of ‘road’ in Michigan, mostly dirt roads dividing the grid. Less than 400 kilometers of the roads were paved at the time, although there was already 12,000 kilometers of gravel road. Michigan thus had a somewhat more developed road network of improved roads than many other states at the time, due to the early industrialization of the state. Woodward Avenue in Detroit was Michigan’s first concrete road in 1909. In 1913, the State Reward Trunk Line Highways Act was passed, a law that provided funding for 4,800 miles of highway in Michigan. After the Federal Aid Road Act from 1916 federal money also became available to the states. One of the requirements was that the states should have a ‘Department of Highways’ or equivalent. Michigan had already had this for 11 years, many other states then had to hastily set up a ministry to qualify for federal funding. In 1917 the first road marking was applied and from the First World War the first organized snow removal was carried out.

In 1919, the State Trunkline Highway System was established, with these state highways also numbered. Michigan was the first state after Wisconsin to have signposted road numbering in the United States. In 1920, the first traffic control installation was installed at the intersection of Woodward Avenue and Michigan Avenue in Detroit. In 1926, the US Highways in Michigan were introduced, already renumbering or deleting the first M numbers. In 1929, the iconic Ambassador Bridge on the Detroit border with Canada opened to traffic. This was the first fixed line between Michigan and Canada in the Detroit area. The Detroit-Windsor Tunnel opened a year later.

In 1941 the construction of freeways was approved. The first freeways were built in Detroit during World War II. Detroit was the first city in the central United States to have freeways. Opened on November 24, 1942, the M-8 (Davison Freeway) in Detroit was the world’s first sunken highway. The Detroit area was one of the few areas in the United States where new roads were built during World War II. In many other states, spending on the road network was minimal because everything was devoted to warfare.

Just after the Second World War, much more money became available for the development of the road network, partly due to an increase in fuel excise duties. In 1951, the Michigan Turnpike Authority (MTA) was created with the goal of building a north-south toll road through Michigan. This was initially planned from the Ohio border to near Saginaw. However, there was friction between an independent toll highway operator and the traditional highway operator, causing the construction of the toll highway to be delayed and eventually scrapped after the creation of the Interstate Highway system in 1956. The first Interstate Highway to be signposted was I-75 between Toledo and Detroit. in 1959. This highway was already opened in 1957.

Michigan made great strides in building freeways, both Interstate Highways and non-Interstates, with a significant portion of the highways opening in the 1950s and 1960s. By 1964, I-94 was completed from the Indiana border to Port Huron. In 1957, the iconic Mackinac Bridge opened in the north of the state. In the early 1960s, the last state highway was also asphalted, the last gravel road was M-48 in Chippewa County on the Upper Peninsula. Michigan’s goal was to connect any place with more than 50,000 residents with freeways.

In 1973, the last link of I-75 between Alger and Roscommon opened in the middle of the state. Michigan was one of the first states to complete the highway plan. Since the second half of the 1970s, the focus has shifted away from new construction and more towards maintenance and upkeep of the road network. Some planned freeways in the Detroit area have not been constructed as planned. One project, however, was incomplete, Detroit’s northern bypass. The last section of Interstate 696 opened to traffic on December 15, 1989. In 1992, the last 6 miles of Interstate 69 opened at Lansing, completing the planned Interstate Highway network, although in fact the vast majority of it had been completed 15 years earlier.

Rattle Strips

Between 2008 and 2010, the US state of Michigan installed a rattle strip on the center line on 8,700 kilometers of state highway and another 2,700 kilometers of rattle strips on the side marking / hard shoulder. This very extensive implementation of rattle strips in a short time allowed a representative effect study.

The implementation of rumble strips on thousands of kilometers of road has significantly reduced accidents;

  • 50% fewer frontal collisions
  • 46% fewer collisions where vehicles run off the road
  • 51% fewer fatal accidents
  • 41% fewer accidents with permanent injuries

Michigan Road Network