The first Michigan road map, with only three roads on it, was published by the United States Congress in 1826.
Michigan's first four-lane divided expressway, the Detroit Industrial Expressway, ran between Detroit and Willow Run in 1941.
The shortest state trunkline road is M-212 in Cheboygan County. It is only .7 mile long.
The longest highway in Michigan is I-75, which runs 395 miles from the Ohio border to the International Bridge in Sault Ste. Marie.
Michigan has a total of 120,256 miles of paved roadway (9,669 route miles of state trunkline, 89,444 route miles of county roads, and 21,198 route miles of city and village streets).
There is enough pavement in Michigan roadways to build a one-lane road from the Earth to the moon.
More than 95.1 billion miles are driven on Michigan roadways every year.
M-185 on Mackinac Island is the only state highway in the nation where motor vehicles are banned.
The shortest freeway in Michigan is I-375 in Detroit. It is only 1.1 miles long.
Eight Michigan highways began as Native American trails, US-2 (from Sault Ste. Marie to Green Bay); I-75 (from Detroit to Saginaw); I-94 (from Detroit to St. Joseph; I-96 (from Detroit to Grand Rapids); I-94 (from Detroit to Port Huron); US-41 (from L'Anse to Marquette); and US-12 (from Ypsilanti to Chicago).
The first surveyed road in Michigan was Pontiac Road (now called M-1 or Woodward Avenue) connecting Detroit and Pontiac in 1819.
The three-span US-12 camelback bridge in Mottville is Michigan's longest remaining bridge of this type.
One of the most unique bridges in Michigan is the siphon bridge carrying old US-2 over the Manistique River. The bridge deck is actually four feet below the water level, and has been featured in "Ripley's Believe it or Not!"
The first border-to-border concrete highway was M-16 from Detroit to Grand Haven in 1920.
There are 10,754 roadway bridges in Michigan. Of these, 4,411 are on the state highway system and 6,343 are located on county roads or city streets.
The statutory width of Michigan's road right of way is 66 feet, or two rods (33 feet), on each side of each section line.
There is only one driveway onto a Michigan interstate freeway: a gated entrance to I-94 to allow movement of military vehicles at the former Fort Custer, west of Battle Creek.
The towers on the Mackinac Bridge (552 feet high) are almost as tall as the Washington Monument (555 feet high).
Adopt-A-Highway volunteers have removed more than 2 million bags of trash from state roadsides since the program began in Michigan in 1990. Approximately 3,178 citizen volunteer groups pick up trash three times a year on nearly 6,700 miles of state highways.
In 1956, Michigan became one of the first state highway departments to use a digital computer to perform highway computer programming work.