Diverging Diamond Interchange

Want to avoid gridlock? Drive on the wrong side of the road. In July, traffic engineers in Springfield, Missouri, reconfigured the jammed I-44/Kansas Expressway interchange. The new design does away with risky left turns. The street approaching the highway now diverts to the left, and cars get uninterrupted access to the highway, which, experts say, can reduce clogging by as much as 60 percent. Think of it as a one-way street. Drivers who want to turn left onto the highway can do so without crossing oncoming traffic. Through-traffic, meanwhile, stays on the left side of the road until it reaches a second stoplight, where it passes back over to the right. The Federal Highway Administration estimates that the diverging diamond configuration, the first in the U.S., enables 600 left turns onto the freeway per hour per lane—double that of an ordinary interchange, where drivers cross oncoming traffic. Plans are under way to implement similar designs around Kansas City and St. Louis.
modot.mo.gov