Diverging diamond needs a little polish, but is open to traffic
The state’s first diverging diamond interchange — a cutting-edge road design — was open to traffic east of Fruita on Friday, state officials said.
The project to reconstruct the interchange between U.S. Highway 6&50 and Interstate 70 is almost complete, with landscaping, striping and safety barriers still to finish, Colorado Department of Transportation officials said.
Years in the making, the project was conceived to increase traffic efficiency and safety, officials said.
Traffic will be limited to one lane in each direction until the project is complete, they said.
Some partial lane and shoulder closures will be required for work on the remaining improvements such as landscaping, signage, sidewalks and revegetation, according to a news release.
The speed limit will remain at 30 mph until work is complete, CDOT said.
Orange cones and yellow-jacketed workers will disappear from the area in advance of an official grand opening planned for April, said Rob Beck, resident engineer for CDOT in Grand Junction.
The diverging diamond is expected to improve efficiency by reducing wait time for left-hand turn movements, Beck said.
Perhaps even more important is the increased safety the new design will provide area motorists, he said.
HOW THE INTERCHANGE WORKS
The I-70 interchange eliminates traditional left-hand turns by crossing lanes and shifting drivers to the left side of the road through the interchange, he said.
This gives drivers direct access to a left-hand ramp to access the interstate without waiting at a traffic signal, Beck said. The lanes then shift drivers back to the right side, he said.
Opening of the exchange comes after a nearly two-month delay in construction caused by winter weather, Beck said.
Because the design is so new, most drivers will notice a significantly different traffic pattern through the interchange.
“The diverging diamond is counterintuitive,” Beck said.
People confused by roundabouts may take awhile to become comfortable with the interchange, he said.
“If you look at an aerial picture of a (diverging diamond interchange), you may think that it could be a challenge to drive through,” Beck said. “But in reality, a DDI is like every other interchange and has signs, pavement markings and traffic signals to guide motorists through it.”
DIAMOND INTERCHANGE ADVANTAGES
Diverging diamond interchanges can carry much more traffic than conventional interchanges, and the capacity for left-turn movements is twice that of a conventional interchange, Beck said.
“The amount of crashes are reduced as are the severity of crashes,” he said. “The accidents that do occur are at angles that eliminate the dangerous T-bone that can happen at a traditional intersection.”
The total cost of the interchange was $4 million. Other alternatives for interchange reconstruction were estimated between $10 and $15 million, according to CDOT.
“Minimal right-of-way acquisition is required for this type of interchange,” Beck said.