[b] Other responsibilities that fall under MDOT's mandate include airports, shipping and rail in Michigan.

The predecessor to today's MDOT was the Michigan State Highway Department (MSHD) that was formed on July 1, 1905 after a constitutional amendment was approved that year.

The first activities of the department were to distribute rewards payments to local units of government for road construction and maintenance.

The department continued to improve roadways under its control through the Great Depression and into World War II.

[4] The attention of Michigan residents was turned to the good-roads movement by Horatio S. Earle, the first state highway commission.

The department was formed, and Earle was appointed commissioner by Governor Fred M. Warner on July 1, 1905.

[3] At first the department administered rewards to the counties and townships for building roads to state minimum specifications.

Work began by the Wayne County Road Commission on April 2, 1909 and finished on July 4, 1909, at a cost of $13,354 (equivalent to $323,967 in 2023[6]).

Automobile registrations surged to 20 times the level at the department's formation, to 60,438, and there were 1,754 mi (2,823 km) of roads built under the rewards system.

Passage of the "State Trunkline Act" provided for 3,000 mi (4,828 km) of roadways with double rewards payments.

[8] Further legislation during the Rogers administration allowed for special assessment taxing districts for road improvements, taxation of automobiles based on weight and horsepower and tree-planting along highway roadsides.

That same year, the first stop sign was put in place and the country's first "crow's nest" traffic signal tower was installed in Detroit.

[11] This winter maintenance started during World War I to keep 590 mi (950 km) of strategic highways clear.

[12] The first ferry service was started on July 1, 1923, linking Michigan's Upper and Lower peninsulas.

Roadside picnic tables, soil testing and aerial surveying of highways also debuted at this time.

The biggest bridge designed by the department spanned the River Rouge carrying the Fisher Freeway (I-75).

An executive order by Governor William G. Milliken gave the department authority over all transportation programs in Michigan.

The Michigan Aeronautics Commission is charged with creating rules regarding airports, related facilities and pilot training.

[29] MDOT is organized into seven regions statewide and a series of divisions and bureaus that report through two chief officers to the department director.

The chief administrative officer oversees the sections of the department related to aviation and aeronautics, finances, transportation planning and human resources.

The offices devoted to communications, passenger transportation and business and economic affairs report to director of the department.

[29] The department provides subsidies to Amtrak Michigan Services operations in the state for the Blue Water, Wolverine and the Pere Marquette lines.