 In a view that won't last much longer at the Fillmore/I-25 interchange, eastbound traffic (foreground) travels over Fillmore's new south bridge while oncoming westbound vehicles use the original bridge (built in 1960). The contractor, SEMA Construction plans to put the new north bridge (far left) into service soon, simultaneously realigning Fillmore over the interstate in a "diverging diamond" layout. The old bridge will then be demolished. The $15.1 million Colorado Department of Transportation (CDOT) project - long advocated by local officials - started in February 2015, with a June completion date tentatively anticipated. Westside Pioneer photo
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Probably by the end of March, Fillmore Street over the interstate will be reconfigured into what's called a diverging diamond interchange (DDI) layout, according to Ted Tjerandsen of Wilson & Co., project consultant for the Colorado Department of Transpor-tation (CDOT).
In the DDI, Fillmore Street drivers from either direction will find themselves switching sides as they travel over the interstate (see graphic on back page).
The change will make Fillmore/I-25 one of a handful of interchanges in the United States to use the relatively new design, which traffic engineers believe is safer because it avoids the need for left-turn signals at on-ramps.
Like dominos, the realignment is part of a series of construction events in March and April in which each result makes possible the next, with ultimate completion of the $15.1 million project tentatively expected in June.
 A graphic displayed at a pre-project open house shows the basic layout of the diverging diamond interchange that will soon be implemented at Fillmore/I-25. A stoplight will be at either end, allowing the two directions to cross over safely. Courtesty of Colorado Department of Transportation
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Leading up to the DDI switch has been the preparation of the new north bridge, which the contractor, SEMA Construction installed in December. In the meantime, westbound traffic has continued using the original bridge (built around 1960), which sits between the two new structures.
The DDI “domino” is planned to occur on a weekend around the end of March (weather-dependent). To allow the necessary restriping of the street's pavement, Fillmore and its interstate ramps will be closed on that Friday, Saturday and Sunday night (from about 9 p.m. to 5 a.m.) , Tjerandsen said.
Opening the north bridge at that time will also mean discontinuing use of the old bridge.
The plan is to finish the striping no later than the wee hours at the end of the weekend so the DDI will be fully operational for Monday-morning rush-hour traffic, Tjerandsen said.
The next step will be to demolish the old bridge. That will require overnight closures of the interstate and Fillmore in both directions, with the destruction occurring between a Sunday and a Thursday (nights that have less traffic), he said.
When the demo is out of the way, the raised medians to permanently mark the DDI can go in, he added.
A final layer of pavement and permanent lane striping will follow.
Ongoing work away from the bridges involves lengthening the southbound off-ramp and northbound on-ramp.
Westside Pioneer article