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Columbia Missourian

French-style interchange proposed for Stadium, I-70

By Alison Gammon
February 12, 2010 | 12:01 a.m. CST

The diverging diamond design is cheap, simple and easy, according to MoDOT.

MoDOT is considering implementing a Diverging Diamond Interchange at Stadium Boulevard and Interstate 70. The design, modeled after the U.S.'s first interchange in Springfield, would accommodate more traffic, decrease congestion and improve safety.   ¦  Amy Brachmann

COLUMBIA — The state plans to create a diverging diamond interchange, inspired by the French, for the intersection of Interstate 70 and Stadium Boulevard. The interchange would be only the second of its kind in the country.

Thus far, the only interchange in the country that features the design, which originated in Versailles, France, is in Springfield, where it has reportedly been quite popular.

"It's been well received. People call in and say they love it," said Don Saiko, the Missouri Department of Transportation's project manager for the Springfield interchange.

MoDOT sent a survey to 400 people seeking their opinions of the interchange. Saiko said 75 people responded, and their comments were overwhelmingly positive.

"The traffic on Friday before the new interchange was terrible, often backing up 1-3 minutes. I haven't noticed any backup lately," one survey respondent wrote.

Saiko said the $3.2 million project was much cheaper than the alternatives. The different design also proved to be safer and more efficient. Comparing the first four months' use of the interchange to four months in 2008, the interchange yielded a 60 percent reduction in accidents and helped traffic move considerably faster, Saiko said.

Given that success, MoDOT plans to use the strategy when it rebuilds the intersection of Stadium and I-70 as well as in a St. Louis interchange.

Matt Myers, district traffic engineer for MoDOT, said the design is simple, cheap and easy and that it should relieve congestion at the Stadium intersection. The design allows for only two traffic signals at the interchange, improving efficiency and cutting down on the amount of time drivers are stuck in traffic.

The Springfield version, which opened in July 2009, took only four months to build.  Myers said the Stadium interchange will be rebuilt by 2013, regardless of which design is ultimately used.

Myers said the diverging diamond is still in the proposal stage. MoDOT will eventually present information on the design to City Council*.