CASTLE ROCK • Interstate 25 commuters: Get used to traffic barriers and orange drums.
As the stretch of I-25 from Monument to Castle Rock becomes the longest construction zone in the state, the Colorado Department of Transportation is encouraging residents to plan ahead for closures, restrictions and other obstacles.
Crews are adding a pair of toll lanes to the 18-mile stretch known as “the Gap” to widen it from two to three lanes in each direction. The $350 million cost is being covered by state and local governments, including El Paso and Douglas counties.
“We expect that the project will be completed by fall of 2022,” CDOT spokeswoman Tamara Rollison said at a Tuesday news conference in Castle Rock.
“Between now and then, you will see major sections of the roadway completed.”
Here’s what drivers can expect this summer:
Renaissance Festival traffic
Larkspur residents are bracing for backups, as the construction likely will exacerbate the heavy traffic to and from the annual Colorado Renaissance Festival, which begins Saturday and continues on weekends through early August.
An auxiliary lane on the interstate’s shoulder will be open Friday afternoons through Monday mornings between Sky View Lane and Spruce Mountain Road this summer to ease the festival traffic congestion, CDOT reports. Safety patrols also will be bolstered on Sundays.
This month, I-25 southbound traffic near the Monument weigh station will be shifted to the northbound side for about two months, with a barrier to separate it from northbound traffic. Northbound traffic later will be shifted to the other side as crews add lanes and wider shoulders to part of the Gap.
More traffic crossovers are slated for the Greenland Road area, with northbound traffic soon to be shifted to the southbound side so interchange reconstruction can begin.
Another traffic shift will occur between Castle Rock and Larkspur, where crews have been working in the center median since September. The realignment in August, to be in place through the end of 2019, will allow crews to begin working on the outside of I-25.
Impacts to frontage roads
Workers will flag traffic on I-25 frontage roads through the summer, and drivers will need to slow to 40 mph. Some closures will be required, but crews will not shut down frontage roads east and west of I-25 simultaneously. When no flagging is done, the roads’ speed limits will be 45 mph.
Ramp and lane closures
Two lanes will remain open in each direction of the Gap during daytime, barring emergencies. But crews will need to institute some nighttime, single-lane closures to prepare for traffic shifts and do other work.
Construction also might periodically cut drivers’ access to on- and off-ramps at County Line Road, Sky View Lane, Spruce Mountain Road and Upper Lake Gulch Road.
In July, each of County Line Road’s ramps to I-25 will close for up to 10 days so crews can rebuild them and improve drainage. Residents who live off County Line Road still can access their homes via detours.
The reconstruction of the Greenland Road interchange will require ramp closures, too.
And late this summer, the northbound I-25 on-ramp from Sky View Lane will close temporarily.
More law enforcement will be in the construction zones, especially during lane closures.
CDOT requires its contractor to have tow trucks available so any idle vehicles can be removed as quickly as possible.
Speed limits in the construction areas will be reduced to 65 mph or less.