Construction on the Interstate 25 South “Gap” project hit significant milestones in 2020 and major work will continue this year, project officials said Thursday.
Since work on the $350 million project began in September 2018, “We have made tremendous progress on this project,” Colorado Department of Transportation spokeswoman Tamara Rollison said. “The most important reason for this project is safety. We’re improving road alignment and capacity. It will be like driving on a brand-new road once it’s complete.”
The department rounded out the tail end of 2020 with the completion of a highway interchange and two new wildlife crossings in December.
The Greenland Road and I-25 interchange was transformed from a one-lane culvert into a full two-lane underpass, according to the department. It opened Dec. 22.
Another bridge at Spruce Mountain Road was also completed in 2020, Rollison said.
Three additional bridges, for a total of five, will be constructed. The Upper Lake Gulch Road Bridge is 40% complete, and the bridge over Plum Creek is halfway complete. Design of the County Line Road Bridge is complete, and construction is expected to begin on that bridge around springtime, Rollison said.
Crews also completed a new southbound climbing lane from just south of Greenland Road over Monument Hill. This will “help ease pressure” between trucks and other vehicles, providing more space for trucks to pass, Rollison said. The climbing lane is currently being used as part of a traffic shift to safely accommodate construction in the area.
The wildlife underpasses — one near the Greenland Road interchange and the other near the County Line Bridge — are each 100 feet wide and 18 feet tall and are designed to reduce the number of collisions between vehicles and animals by 90%, Rollison said.
Construction is underway on two more wildlife underpasses, Rollison said, for a total of four. The remaining two are expected to be completed this year, she said.
Crews have already installed 17 miles of the 28 miles of deer fencing planned for the project. Deer fencing is completed along with portions of the roadway and fencing installation is expected to be completed in 2022, Rollison said.
In August, crews completed construction on the northern five miles of the project between Sky View Lane/Tomah Road and Plum Creek Parkway. The roadway will operate with wider shoulders for emergency response until the express lanes — one in each direction in the 18-mile stretch of I-25 between Monument and Castle Rock — open in 2022.
This stretch of road is in its final configuration and now has three northbound and southbound lanes in each direction.
When the project is completed the roadway will open the new express lanes in each direction during a testing phase and tolls will not be collected, Rollison said. Once the testing phase is complete, tolls will go into effect.
A state board is supposed to set the toll rates before the new lanes open. Transportation officials won’t know the final rate until a few months before the tolls begin to be collected, Rollison said.
Public outreach efforts are expected in the future to obtain feedback on the tolls, she said.
Tolls on the I-25 South “Gap” express lanes could be the lowest in the state and among the cheapest in the country, according to a nearly 500-page traffic and revenue study commissioned by the agency’s High-Performance Transportation Enterprise.
The study recommended a rate of about 15 cents per mile, or approximately $2.25 per one-way trip. That is expected to cover the cost of operating and maintaining the lines, maximize the number of drivers using the toll lane and reduce traffic in all lanes.
Tolls on the third lane being added in each direction has been a sore point with some local residents and officials, who objected to what they claimed amounted to double taxation, since local taxes helped fund the project.
Crews have also completed nearly 60% of paving on the entire 18-mile construction project, placing 468,000 tons of asphalt.
“That was definitely a mile marker for us,” Rollison said.
Paving work will continue on “as much of the remaining stretch as possible” in 2021, she said.
Additionally, 90,000 linear feet of existing fiber-optic line has been relocated to modernize communications and power along the corridor.
The Gap project, funded by a mix of state, local and federal money, is on budget and on schedule, expected to be completed by 2022, Rollison said.
For the latest updates, visit i25gap.codot.gov, or the project’s Facebook page (@I25SouthGapProject).