Not every intersection is created equal, and installing a Michigan Left depends on a few factors, including crash history, type of road, and traffic volumes.
Before a Michigan Left is installed, MDOT will study the crash history and traffic volumes at major intersections along the road to determine appropriate placement. Michigan Lefts are most often used in urban situations where congestion and crashes are more common. Indirect left turns can be built on divided roads with any number of lanes (i.e., four, six or eight lanes), but they are not used on freeways or limited-access roads.
Ideal spacing for Michigan Lefts is between a quarter and three quarters of a mile, but the actual distance is determined by the locations of major crossroads and driveways. Intersections with traffic signals need to be far enough apart that vehicles lined up to turn will not cause significant congestion.
Additionally, there are no absolute maximum/minimum traffic volume requirements for a Michigan Left to be installed. Michigan Lefts increase capacity and safety and have been used on state routes with average traffic volumes between 10,000 and 100,000 vehicles per day.