With the Toledo area’s second diverging-diamond freeway interchange about to open, the Ohio Department of Transportation is well along in planning for third and fourth local examples of the unusual design.
Diverging diamonds, where the interchanging roadway’s lanes cross over each other on either side of the freeway to simplify left turns to and from ramps, are planned for construction at I-75’s Fremont Pike interchange in Perrysburg starting in 2027 and at the Airport Highway interchange on I-475/U.S. 23 in Springfield Township starting the following year.
While still uncommon, the diverging-diamond layout “is becoming prevalent in Ohio and the nation,” said Patrick McColley, ODOT’s district deputy director in Bowling Green, because it has very few “conflict points” where collisions are most likely.
In particular, the layout allows left turns to be made to and from interchange ramps without having to cross opposing traffic. While that can also be set up with dedicated left-turn lanes and arrow phases on traffic signals, a diverging diamond accomplishes it in less space and fewer traffic-signal phases, while ending conflicts when drivers disregard red signals.