Beginning in 1960, the State Highway Department constructed "directional crossovers" on Telegraph Road in order to avoid intersections with "interlocking" left-turns along that trunk line. The directional crossovers would eliminate left turns through the major intersection. Initially, the directional crossover was placed less than 350 feet from the intersection. But this short distance created problems. The main problem was that a driver had to enter traffic and make a lane change in order to be positioned to make a right turn. On-coming traffic often backed-up turning traffic and the lane change tended also to slow traffic, which defeated the whole aim of directional crossovers for left turns at busy intersections.
Joseph Hobrla, a signal engineer for the State Highway Department, and Joseph Marlow, the district traffic engineer, studied these traffic patterns along Telegraph Road and from these observations introduced some innovations at the intersection of Eight-Mile and Livernois. They placed the directional crossover nearly twice as far from the intersection as was done previously on Telegraph Road, some 660 feet from the intersection. On-coming and cross-over traffic was controlled with a signal. A dedicated lane for right turns was added to the right side of the roadway. Thus to make a left turn onto Livernois from Eight-Mile, a driver proceeded through the intersection to the crossover, waited at the light for a clear signal, entered Eight-Mile going in the opposite direction, and changed lanes into the dedicated right-turn lane at Livernois. The introduction of this traffic pattern at Eight-Mile and Livernois proved so successful at keeping traffic moving that over 700 such intersections were constructed throughout Michigan over the next forty years and became known as the "Michigan left-turn."
Stanley D. Lingeman, State of Michigan Trunk Line Story, 3rd ed. (1996), 5.
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