As part of our M I Curious project, Nick Ochal asked Michigan Radio this question:
What is the origin of the infamous "Michigan Left" that befuddles so many out-of-staters?
Last month, Stateside's Cynthia Canty put the question to Joseph Hummer, a professor with the College of Engineering at Wayne State University. According to Hummer, Michigan Lefts emerged as a way to decrease traffic congestion on roads that were designed for street cars.
After this interview aired, a listener wrote in questioning the link between street cars and Michigan Lefts.
"... the connection between the Michigan Left and the street car lines was tangential at best and most definitely not the cause-and-effect relationship the Wayne State University professor made it out to be."
So, what is the true history of this infrastructural oddity?
For all those who may not be so acquainted, a Michigan Left is an intersection at which left turns are not allowed. Instead, to turn left, drivers must drive straight through the intersection and make a median cross-over several hundred feet down the road.
For their history, they quote from a book by Stanley D. Lingeman: "The State of Michigan Trunk Line Story."
Lingeman writes that back in the 1920s, a "Super Highway" was constructed in Detroit as part of the U.S. Highway Program. This highway became crippled by traffic congestion in the years immediately following World War II.
A promising solution came in the form of "directional crossovers" which were implemented in 1960 on Telegraph Road. These crossovers were not quite right -- they were placed too close to the intersection, and failed to resolve the gridlock issues.
Lingeman writes, that's when Joseph Marlow and Joseph Hobrla stepped in:
Joseph Hobrla, the Department's Signal Engineer, was dissatisfied with the traffic flow characteristics of these intersections on Telegraph Road. He and Joseph Marlow, the District Traffic Engineer [for the State Highway Department], decided to experiment with the westbound Eight Mile Road left turn at Livernois Avenue in Detroit.
They moved the "directional crossover" from 350 feet past the cross street to 660 feet - and today's Michigan Left was born.
Today, Lingeman writes, the Michigan Left has been implemented in over 700 intersections.
Though the "Michigan Left" is unusual, it is regarded by the Michigan Department of Transportation as a success. They say the turns have decreased congestion and crashes across the state.
In regards to Hummer's proposed link between street cars and Michigan Lefts, we found no evidence that definitively refuted or supported this connection.
So Stanley D. Lingeman, a man who seems to be, or have been, an employee of the Michigan Department of State Highways and Transportation, seems to be the authority on this history.
We're trying to reach Mr. Lingeman for more information. If you know how to contact him, let us know!
-By Ari Sandberg, Michigan Radio Newsroom