DENVER — A Colorado Department of Transportation project to improve a large section of Interstate 25 in Denver will impact traffic in an already congested corridor.

The five-mile resurfacing project will include new pavement and bridge repair work on I-25 from Alameda Avenue to W. 44th Avenue.

Work is scheduled to begin Sunday night and will continue through January of next year.

CDOT said most lane closures will open overnight, lessening the impact on traffic.

Based on annual average daily traffic data (AADT) provided by CDOT, the corridor is the undisputed gridlock boss when it comes to the state’s most congested highways, with close to 300,000 vehicles passing through daily.

The Central I-25 Corridor was scheduled to see an expansion. However, in 2022, CDOT nixed a $1.5 billion proposal to add a fifth lane to I-25 from about Speer Boulevard to Santa Fe Drive, citing negative feedback from the public and local governments in the area.

Here is what to expect:

• April 6 through late April to early May, 9 p.m. to 6 a.m., Sundays – Thursdays: crews will replace barriers along southbound I-25 between the US 6 ramp to Alameda Avenue. This will require overnight closures of the east and westbound US 6 on-ramps to southbound I-25 and the southbound I-25 off-ramp to Alameda Avenue. There will also be single lane and shoulder closures on southbound I-25 in this area. Detours for the ramp closures will be in place. See detour information below. 
• Resurfacing work will begin once nighttime temperatures are consistently warm enough for asphalt paving.
• Mid-May through late October, 9 p.m. to 6 a.m., Sundays – Thursdays: a single lane closure at 9 p.m. and then up to three lanes closed in each direction a few hours later on I-25 between Alameda and 44th avenues.  All lanes will re-open before 6 a.m.
• While most of the lane and ramp closures will take place at night when traffic volumes are at their lowest, motorists should expect some delays. There could be weekend lane closures during the day and night as well. The project team will adjust closure times depending on major events in the area.
• Motorists are urged to drive with extra caution through the work zone, watch for crews, heed the signs, do not speed and leave plenty of following distance.
• Overhead electronic signs, other signage and traffic cones will be set up well in advance of the closures to warn motorists.
• Motorists can sign up for project updates by going to https://www.codot.gov/projects/i25centralresurfacing, and get lane closure information and real-time traffic conditions on cotrip.org.

Ramp Detours 9 p.m. to 6 a.m., Sundays-Thursdays in April

• US 6 On-Ramps to Southbound I-25 Detour:
  • Motorists traveling on east or westbound US 6 will take southbound Kalamath Street to the Santa Fe/Kalamath on-ramp to southbound I-25.
• Southbound I-25 Exit Off-Ramp to Alameda Avenue Detour:
  • Motorists traveling on southbound I-25 will take the Santa Fe Drive Exit, proceed on South Santa Fe Drive, then turn left to cross Mississippi Avenue over South Platte River and then turn left on North Santa Fe Drive to Alameda Avenue.