Center Junction to get major makeover

The Missouri Department of Transportation (MoDOT) plans to replace the Interstate 55 bridges over Highway 61 between Cape Girardeau and Jackson and redesign the entire interchange, a state highway official said Thursday.

The project would eliminate the grassy median at Center Junction, said MoDOT project manager Jason Williams with the agency's Southeast District.

Construction on the approximately $10 million project is expected to begin in the summer of 2019 and take two construction seasons, with completion expected by fall 2020, said Williams.

He said the project is needed because the Interstate 55 northbound and southbound bridge decks are "beginning to get in pretty bad shape."

The 600-foot spans date back to the opening of Interstate 55 in Cape Girardeau, Williams said. According to Southeast Missourian archives, the bridges are nearly 50 years old.

By reconfiguring the interchange, the new bridges will each span about 200 feet, reducing the cost, Williams said.

Eliminating the grassy median and constructing a concrete barrier between the eastbound and westbound lanes of Highway 61 will allow for shorter bridges to be built over it, he said.

Plans call for eliminating the grassy median from Old Orchard Road on the Jackson side to the Veterans Home and the Sportsplex on the Cape Girardeau side. It would then transition back to a grassy median. The section of the grassy median that runs in front of Cape Girardeau County Park would remain, Williams said.

As currently designed, the project would include construction of a "diverging diamond" interchange, he said.

With this design, the two directions of traffic on the non-freeway cross to the opposite side at the overpass.

MoDOT's website calls a diverging diamond interchange "a new type of interchange traffic solution."

The nation's first diverging diamond interchange was completed in 2009 in Springfield, Missouri, the website stated.

Traffic models indicate this type of interchange works well with areas of heavy traffic, MoDOT explained on its website.

Williams said the benefit of this design is motorists making left turns no longer would have to turn in front of oncoming traffic. It allows for better traffic flow onto the Interstate ramps, he said.

"It should operate more efficiently," Williams said of Center Junction.

Cape Girardeau city planner Ryan Shrimplin said the Center Junction project would mark the first diverging diamond interchange in the area.

Shrimplin said city officials were aware MoDOT planned to replace the I-55 bridges, but only recently learned about "the extensive changes" planned for the underpass.

Williams said one I-55 bridge would be replaced at a time, allowing for one lane of traffic to flow in each direction during construction.

The construction is not expected to completely shut down Highway 61 either, he said.

"It is a heavily traveled route," Williams said of the state route that connects Cape Girardeau and Jackson.

According to Williams, 22,000 vehicles a day travel that stretch of Highway 61.

"We should have minimal closures," he said.

Construction will involve some "short-term inconvenience" for motorists, but provide long-term improvements, according to Williams.

Williams said it makes sense to rework the entire interchange when replacing the bridges because the spans are expected to last another 50 to 75 years.

Federal and state funding are in place for the project, he said. Design work is being finalized, he added.

MoDOT plans to hold a public meeting in late spring to discuss the project, Williams said.

mbliss@semissourian.com

(573) 388-3641

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diverging diamond interchange

More information about diverging diamond interchanges can be found on the MoDOT website:

http://www.modot.org/central/major_projects/DivergingDiamond.htm