MoDOT Opens Nation’s First Diverging Diamond Interchange

Ever drive on the left side of the road? A highway design common in Europe is now giving Springfield, Mo. motorists this unique experience.

MoDOT opened the first-in-the-USA Diverging Diamond Interchange in June at the intersection of Kansas Expressway (Route 13) and Interstate 44 in Springfield.

Signs, pavement markings and concrete islands at the new interchange guide drivers on Route 13 as they criss-cross at traffic signals on both sides of the bridge at Interstate 44. That puts oncoming traffic on the right, but separated by concrete barriers that also form a pedestrian walkway down the center.

Left-turning vehicles on Kansas Expressway get a "free left" onto the I-44 on-ramps. At the same time, two lanes of traffic continuing north or south on Kansas Expressway are able to travel more steadily through the interchange.

A DDI is a great solution in high traffic areas. Motorists no longer have to cross opposing traffic. Left turn crashes are eliminated and the chance of being in a rear end crash is reduced. Motorists spend less time being stuck in traffic, which is also good for the environment as idle time is reduced at the interchange. Plus, Springfield’s DDI design came out to be cheaper and shaved about a year-and-a-half off the construction time.

Look for similar Diverging Diamond projects in Missouri, including one on National Avenue at the James River Freeway (Route 60) in Springfield and in Kansas City and St. Louis.