The Fillmore Street/I-25 interchange got a $2 million gift.
That gift guarantees the $13 million highway project will be fully funded.
"It was originally an $11 million project," said Jason Wilkinson, spokesman for the Pikes Peak Area Council of Governments. "Then the Colorado Department of Transportation came back a few months ago and it ended up being a $13 million project," Wilkinson said. "This is finding that last $2 million. This is the money that will finish it."
The interchange was approved as part of the state's Responsible Acceleration of Maintenance and Partnerships Program in 2013. That program allowed CDOT to advance $300 million a year for five years to pay for projects, or $1.5 billion for transportation projects statewide.
The diverging diamond interchange is yet another look at the future of interchanges in Colorado.
Roundabouts are popping up with increasing frequency on surface streets as transportation officials and developers look for cheaper, safer alternatives to interchanges and intersections.
The Fillmore diverging diamond interchange will be among the first built in the state. A similar interchange opened this year in Grand Junction. And construction was to start in March on another in Fort Collins.
Fillmore interchange construction is set to begin at the end of summer and be done in a year to 18 months.
The additional funding was triggered by PPACG board approval of an amendment to its Transportation Improvement Program.
As a result, $1.3 million will come from returned federal funds, while CDOT will provide the remaining $700,000, according to project documents.
Work underway at the intersection is part of the effort to move Chestnut Street west to ease traffic congestion in the area.
Colorado Springs drivers will have to learn to use the diverging diamond interchange, Wilkinson said.
You can compare it to the learning curve with the area's growing number of roundabouts.
"It's like traffic circles," Wilkinson said.
"Traffic circles are safer for traffic flow, but they take some getting used to. People are not always too excited about it."
According to a Missouri Department of Transportation survey, 97 percent of drivers feel safer in the Springfield diverging diamond interchange compared with the previous interchange.
That interchange, built in 2009, was the first of its kind in the United States.
Crash data showed a 60-percent reduction in collisions in a five-month period.
"They handle heavier traffic and there are fewer conflict points," Wilkinson said.
"The big question will be whether the public likes it. They take some getting used to."
Confusion can arise because drivers are shifted to the other side of the road.
"In your mind, if you can get past the thought that you will be driving on the opposite side a little bit, it will be good," Wilkinson said.