Northland motorists recently acquired their first relatively rare kind of diamond — only the fourth of its kind in the Kansas City area.
It doesn’t sparkle, but it does promise to make drivers’ lives easier and help pave the road for economic development in the vicinity.
It’s called a diverging diamond interchange, and it’s at Interstate 29 and Northwest Tiffany Springs Parkway. The Missouri Department of Transportation built the first one in the nation, in Springfield in 2009.
The interchange became operational over the summer, MoDOT spokeswoman Michele Compton said. MoDOT broke ground Sept. 15 on the Kansas City area’s fifth DDI, at Interstate 49 and Missouri 291 in Cass County.
MoDOT started the Northland project in late March of 2013, said Shelie Daniel, MoDOT’s engineer for the Northland. Daniel oversees all of MoDOT’s activities in Platte, Ray and Clay counties.
“They’re an economical solution to a traffic problem,” Daniel said of the DDIs. “One thing I’ve noticed with our diverging diamond interchange design is that for areas that are already developed, it doesn’t take away as much right of way from existing businesses, but it still provides better traffic flow, and it’s lower cost.”
With a DDI, traffic crosses from the road’s right side to its left side at two intersections with traffic signals, one on each side of the interchange, according to MoDOT’s website. This enables free-flowing right turns before the cross-overs and free-flowing left turns between the cross-overs, meaning vehicles don’t cross opposing traffic.
Traffic models indicate that DDIs work well in heavily trafficked areas because they improve safety and traffic capacity, according to MoDOT.
“It reduces the amount of conflict points,” Daniel said. “Before, the traffic did not flow through there efficiently.”
MoDOT estimates that traffic through the interchange will grow from its current 20,000 vehicles a day to 45,000 vehicles a day in 2030, Daniel said.
That’s attributable mainly to projected population and business growth in the Twin Creeks area in Platte and Clay counties, said Alicia Stephens, executive director of the Platte County Economic Development Council.
The project cost about $14 million. MoDOT and the KCI Corridor TIF Commission split the cost evenly, and the Kansas City Aviation Department kicked in $3.5 million as part of the commission’s contribution, Stephens said.
“This (tax-increment financing) doesn’t collect real estate or personal property taxes, but only economic activity taxes — in this case, 50 percent of the sales tax in the TIF plan,” Stephens said. “For KCI Corridor TIF, the majority of projects have been transportation projects. We in Platte County have become well-versed in looking for partners for funding projects.”
As part of the project, a fourth northbound lane was added on Northwest Prairie View Road south of Tiffany Springs Parkway. It connects with Northwest Congress Avenue, creating an alternative route to a nearby recreation complex, Zona Rosa and the Barry Road business district. An additional southbound lane’s design is underway, Daniel said.
The new interchange benefits Kansas City International Airport because it gives the KCI Intermodal BusinessCentre tenant traffic off Northwest Prairie View Road quicker access to and from I-29, Aviation Department spokesman Joe McBride said in an email.
“Also, this improvement will help the future extension of Tiffany Springs Parkway to the west of I-29 across the south side of KCI,” McBride said. “The future of the KCI intermodal facility is to the south of its current phases, and (the) Tiffany Springs extension will be important for access.”