The bill creating the state trunkline highways was passed on May 13, 1913.
The State Reward Trunk Line Highways Act also provided for surveying, improving and maintaining those highways.
Before that, county road commissions, which began in 1893, handled such matters, but they weren’t very engaged — with only 18 of the state’s 83 counties participating — according to Michigan Department of Transportation historian Lloyd Baldwin.
In 1905, things improved when the Michigan Legislature authorized the state to get involved and funds from motor vehicle registrations, initially introduced in 1905, were awarded to road commissions that brought roads up to state standards — $250 per mile for gravel roads and $1,000 for macadam roads, depending on improvement types and inclines.
The Michigan State Highway Department, predecessor to the Michigan Department of Transportation, was authorized in 1919 to take over the state trunk line system and ordered to sign the numbered system, making Michigan the second state in America to do so (Wisconsin was first).
“Many farmers, and even Henry Ford, despite being on the first road commission in Wayne County, opposed the state’s efforts to improve existing roads and to build new roads. Farmers didn’t want the traffic and Ford was certain his vehicles could handle any sort of road condition,” Baldwin said in an e-mail.
The U.S. highway system was developed in 1926.
Michigan has 9,716 miles of state trunk line.
For the full article, see Zlati Meyer, “1913 bill created Michigan’s trunkline highways”, Detroit Free Press, May 9, 2015.