The Michigan Department of Transportation (MDOT) is a key government department established by the state constitution of Michigan. Its main job is to manage and maintain the Michigan State Trunkline Highway System. This system includes all Interstate, US, and state highways in Michigan, except for the Mackinac Bridge. MDOT also oversees responsibilities related to airports, shipping, and rail transportation in the state.

Before MDOT existed, the Michigan State Highway Department (MSHD) was created on July 1, 1905, after a constitutional amendment was approved that year. The department’s early work focused on giving money to local governments for building and maintaining roads. In 1913, the state legislature approved the creation of the state trunkline highway system. At that time, MSHD gave double the usual payments for roads that became part of this system. These highways were numbered in 1919, making Michigan the second state to use numbered signs on its roads.

During the Great Depression and World War II, the department continued to improve roads under its control. During the war, the state built its first freeways. These freeways later became part of Michigan’s section of the Interstate Highway System.

Starting in the mid-1960s, the department changed its structure. It was briefly renamed the Michigan Department of State Highways. Later changes added responsibilities for all forms of transportation to the department’s work. In August 1973, the department was renamed the Michigan Department of State Highways and Transportation by executive order. The name was later shortened to the current name, the Michigan Department of Transportation.

History

The first State Highway Department was created on July 1, 1905. This department began because of the Good Roads Movement at the start of the 20th century. Members of the League of American Wheelmen, who were bicycle riders, pushed for better roads. They wanted roads that could be used safely by bicyclists without being blocked by horse-drawn vehicles. This movement led the Michigan State Legislature to create a State Highway Commission in 1892. A law in 1893 allowed voters in each county to form county road commissions. Horatio S. Earle, the first state highway commissioner, helped bring attention to the good-roads movement. In 1900, he organized the first International Road Congress in Port Huron and built a 1-mile (1.6 km) macadam road. He also ran for the state senate in 1900 with support from the Detroit Wheelmen bicycle club.

The legislature created a reward system for highways and formed the State Highway Department with a Highway Commissioner. Earle was appointed by Governor Aaron Bliss. However, the attorney general later said the law was unconstitutional, so the department and Earle’s position were canceled. A constitutional amendment in 1905 fixed this issue. The department was then created again, and Earle was appointed commissioner by Governor Fred M. Warner on July 1, 1905.

At first, the department gave rewards to counties and townships for building roads that met state standards. In 1905, Michigan had 68,000 miles (110,000 km) of roads. Of these, 7,700 miles (12,000 km) were improved with gravel, and 245 miles (394 km) were macadam. The state’s "statute labor system" ended in 1907. This system allowed farmers and horses to work on road improvements instead of paying road taxes. Instead, a property tax system was used to fund permanent road improvements, not maintenance. The first mile of concrete roadway in the United States was built along Woodward Avenue in Detroit between Six Mile and Seven Mile roads. This road was 17 feet 8 inches (5.38 m) wide. Work started on April 2, 1909, and finished on July 4, 1909, costing $13,354 (about $332,472 in 2024).

In 1913, voters elected Frank Rogers as highway commissioner. This was the first election for this position after the legislature made it an elective role. Automobile registrations increased to 60,438, which was 20 times higher than when the department was created. By 1913, 1,754 miles (2,823 km) of roads were built under the rewards system. The "State Trunkline Act" provided for 3,000 miles (4,828 km) of roadways with double rewards. Later laws allowed special tax districts for road improvements, taxed automobiles based on weight and horsepower, and planted trees along highways. The commissioner was also allowed to name all unnamed state roads and post signs with town names and distances.

The centerline was first invented in 1911 in Wayne County by Edward N. Hines. It was first used on a state highway in 1917 along the Marquette-Negaunee Road, now County Road 492 in Marquette County. That same year, the first stop sign was installed, and the first "crow’s nest" traffic signal tower was built in Detroit. This traffic light used red, yellow, and green lights and was created by William Potts, a Detroit police officer. Michigan also had the first snowplow, used during World War I to clear 590 miles (950 km) of strategic highways. In 1919, Michigan became the second state after Wisconsin to sign the trunklines.

The first ferry service between Michigan’s Upper and Lower peninsulas started on July 1, 1923. A gasoline tax of $0.02 per gallon (about $0.37 in 2024) was passed in 1923 but vetoed by Governor Alex Groesbeck. It was later enacted in 1926. The highway commissioner gained full control over planning and maintaining state trunklines. By 1927, highway construction used only concrete or asphalt instead of gravel and macadam, after a gas tax increase. In the 1920s, Michigan gained national attention for its highways. The first trunkline built with concrete was M-16, later part of US 16. This road was 20 feet (6.1 m) wide and 7–9 inches (17.8–22.9 cm) thick. At the time, the standard was 16 feet (4.9 m) wide and 6 inches (15.2 cm) thick. Michigan also introduced yellow lines to mark no-passing zones on hills and curves. Roadside picnic tables, soil testing, and aerial surveys of highways were also introduced during this time. As MDOT historians noted, "the age of mud was over; the age of concrete was moving in."

During the Great Depression, highway construction slowed because of lower gas tax and property tax revenues. Starting in 1932, license plate fees were sent to counties for road funding. Road crews made up of "reliefers" (workers from relief programs) helped build roads. Federal aid money was split between the highway department and the welfare department. County welfare agencies provided workers for road projects. Roadside parks and travel information centers were introduced in the 1930s. During World War II, the department built the Willow Run Expressway and the Detroit Industrial Expressway in 11 months to help workers reach Ford Motor Company’s bomber plant at Willow Run. When the Interstate Highway System was created in the late 1950s, Michigan adapted existing freeway plans to meet Interstate standards. In the

Leadership

• Horatio S. Earle, 1905–1909
• Townsend A. Ely, 1909–1913
• Frank F. Rogers, 1913–1929
• Grover C. Dillman, 1929–1933
• Murray Van Wagoner, 1933–1940
• Donald Kennedy, 1940–1942
• Lloyd B. Reid, 1942–1943
• Charles M. Ziegler, 1943–1957
• John C. Mackie, 1957–1965

• Howard E. Hill, 1965–1967
• Henrik E. Stafseth, 1967–1972
• John P. Woodford, 1972–1982
• James P. Pitz, 1982–1991
• Patrick M. Nowak, 1991–1996
• Robert Welke, 1996–1997
• James R. DeSana, 1997–2001
• Gregory J. Rosine, 2001–2002
• Gloria J. Jeff, 2003–2006
• Kirk T. Steudle, 2006–2018
• Mark Van Port Fleet, 2018
• Paul C. Ajegba, 2019–2022
• Brad Wieferich, 2023–present

The Michigan State Transportation Commission makes rules for the Michigan Department of Transportation about transportation programs, buildings, and projects. This commission has six members who serve three-year terms. The Governor of Michigan chooses these members with the approval of the Michigan Senate.

The Constitution of Michigan says no more than three members can be from the same political party.

The Michigan Aeronautics Commission is responsible for making rules about airports, related buildings, and pilot training. This group has five members chosen by the governor and four members who are heads of other departments.

Department organization

MDOT is divided into seven regions across the state and includes several divisions and bureaus that report to two chief officers under the department director. The chief administrative officer is in charge of sections related to aviation, finances, transportation planning, and human resources. The chief operations officer manages the seven regional offices and divisions focused on highway research, design, and construction.

Divisions responsible for communications, passenger transportation, and business and economic affairs report directly to the department director. The Mackinac Bridge Authority works independently to maintain the Mackinac Bridge, but it coordinates its activities through the department director. The International Bridge Administration (IBA) is part of the department and works for the Sault Ste. Marie Bridge Authority, which is responsible for maintaining the International Bridge. The IBA reports to the chief administrative officer.

The Bureau of Aeronautics and Freight Services ensures that the Commission's rules are followed. It includes three divisions: Airports Division, Aviation Services, and Freight Services. This bureau, along with the Passenger Transportation Bureau, was created in 2006 from the Multi-Modal Transportation Services Bureau. The Airports Division manages airport development programs, including planning, design, safety evaluation, and construction. It also licenses airports, flight schools, aircraft, and aircraft dealers, and inspects airports. The division also holds seminars to help pilots stay updated on current procedures. Mike Trout leads the Aeronautics section. The Aviation Services Division helps airports attract and keep airline services. Through the Airport Preservation Program, this division supports at-risk airports in finding ways to remain open.

The department provides financial support to Amtrak Michigan Services for its operations on the Blue Water, Wolverine, and Pere Marquette lines.