Springfield is ahead of the curve when it comes to diverging diamond interchanges.
Since the city of Springfield became the birthplace of America’s diverging diamond concept four years ago, 21 have been built nationwide, according to Missouri Department of Transportation officials. The trend is based on evidence that the European-modeled intersections are reducing accidents and saving driver’s time.
In recent weeks, a fourth Springfield interchange was completed at James River Freeway and Kansas Expressway, marking the 10th in place in Missouri, with Branson, Kansas City and St. Louis all getting in the game. Locally, two more diverging diamond projects are in the works with one at Battlefield Road and Highway 65 and another at Highway 65 and State Highway CC in Ozark expected to be operational by 2015.
Don Saiko, MoDOT project manager for the Southwest District, said the unique interchange systems have drawn attention from around the globe. Saiko said he has talked with traffic engineers from 38 states and given tours to officials from 12 states. In October, he said a group from Australia is scheduled to visit Springfield to assess the system for use Down Under.
“The groups are generally surprised to see how easy it works. I think they expect it to be more complicated,” Saiko said.
The interchanges – which start at $2 million and have been built locally with a combination of state, county and city funds – route drivers to the opposite side of highway interchanges to remove left turns across oncoming traffic and eliminate backups.
A performance evaluation conducted by HDR Engineering Inc. in February 2011 found that left-turn crashes, among the most dangerous according to Saiko, at the Kansas Expressway and Interstate 44 interchange were down 72 percent in the first year of operation, and total crashes were down 46 percent. As well, 80 percent of motorists interviewed said traffic delays had decreased as a result of the interchange.
Saiko said a MoDOT conference in Jefferson City in 2005 that examined three diverging diamonds in France garnered interest from engineers across the state. In 2007, Saiko was tasked with remodeling the interchange at Kansas Expressway and I-44, when he began to draw up plans using the counterintuitive design.
The District 8 Engineer at the time, Kirk Juranas, gave Saiko the go-ahead. “I think it turned out really well,” Saiko said.
The first project led to national awards, including the 2011 American Public Works Association Project of the Year under $5 million, and the design’s popularity has attracted media attention from the likes of USA Today and Time magazine.
Juranas, who has since retired from MoDOT and now works as assistant director of Springfield Public Works, said drivers typically have strong reactions to the interchanges.
“It was well received when it first opened, but people were shocked. They’d say, ‘What did I just go through?’” Juranas said. “We found that you either love it or you don’t, but everyone agrees they work.”
Kansas City was once expected to build the first interchange, according to Juranas, but a bridge project delayed plans there, allowing Springfield to get the claim to fame.
The road work has helped boost the bottom line for Springfield highway contractor Hartman & Co. Inc., which has constructed three of the city’s diverging diamond interchanges – projects valued at $10.9 million, collectively.
Dean Hartman, president of Hartman & Co., which served as the prime contractor for the first project in northeast Springfield, said complaints have been nil.
“They are good for us, good for the city, good for traffic,” Hartman said.
In Springfield, diverging diamonds have ranged in cost from $2.6 million at Chestnut Expressway and Highway 65 to $9.7 million at National Avenue and James River Freeway. The interchange in the design phase at Battlefield Road and 65 is expected to cost $10.2 million, including bridge replacement.
As the interchanges become more prevalent, Saiko said his phone has been ringing less lately.
“Interest is dropping off now. There for a while, it seemed like it was taking half my time between all the calls we were taking and the tours, and then I would go and speak to groups, too,” Saiko said. “As they are becoming more common, I think there are other resources for people interested in them to turn to.”
