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120th Ave. Improvements Project Information

For issues or concerns with the construction, please contact American West Construction at 719.426.3270 or


  • The exit sign is approaching, as all paving and street markings are now complete. Also finished is lighting on the north side of the road.  

    Traffic signals and pedestrian areas are almost finished, although some closures may still occur to accommodate landscaping.  

    The other remaining items include lighting on the south side and installation of water quality stormwater boxes. These boxes clean stormwater before it returns to local streams and rivers.  

    When finished, East 120th Avenue will be widened from two lanes to three in each direction from Sylvia Drive, just east of Washington Street, to the N Line overpass. This will eliminate a bottleneck over that stretch. 

  • August: Pay close attention when you’re driving in the construction area in September. Traffic in both directions will move to the outer edges and the new traffic signals at Irma Drive, Race Street and Claude Court should be turned on by the end of the month. In addition, irrigation and landscaping work has commenced. Off the actual street, the sidewalk should be nearly complete, with a few connectors to finish off. Weather permitting, the project is on track to be complete by the end of September.

  • July 27: Work – both obvious and hidden to the public – continues. The storm drain is nearly complete for the entire project. Underground work is in place for traffic signals at Irma Drive, Race Street and Claude Court. Signal poles, mast arms and cabinets will be installed as soon as they arrive, starting with Race Street.

    On the north side, sidewalk and ADA curb ramps are in place, so crews will soon turn their attention to landscaping. Also, streetlights should start going up early this month on that side.

    And most obvious to the public, paving, sidewalk and curb installation continues on the south side.  

  • May 25 - Rain is great for trees and lawns – not so much for street construction. The unprecedented amount of rain the area has received in May and April slowed down construction on the 120th Avenue Improvements Project. Still, the north side of the project is now on pace to be finished by the end of June (weather permitting, of course.) Traffic will then be shifted to the north lanes, so work can begin on the south.
  • April 25 - Crews are simultaneously working on lighting, curbs, stormwater infrastructure and the street itself. Motorists and pedestrians may notice some dark patches, as lighting is being removed and installed on both sides of the street. Work will soon have a big impact on Irma St. A lot of storm drainage work needs to take place. At least one lane in and out will remain open, but there will be a lot of equipment moving around!
  • March 21 - Construction is progressing well. Be aware traffic goes down to one lane in sections at times. There will be night work at 120th Ave. & Claude Ct. to expedite work and minimize daytime traffic delays.
  • March 3 - Street light relocation is part of this project since the road is being widened. If you are driving through the area and it looks dark in some areas, it's because the lights have been taken out and not yet reinstalled in their new location. All the street lights will be reinstalled (or replaced if they are not in good condition) in stages throughout the duration of the project. 
  • Feb. 27 - The contractor has removed the median to accommodate two lanes of traffic while the expansion of 120th Avenue starts on the north side of the road. Portions of the road and sidewalk have been removed on the north side to begin the installation of underground utilities. 
  • Feb. 18 – To stay on schedule, contractors will begin working on weekends as well as weekdays for the foreseeable future. Watch signs for details.
  • Feb. 2 – Speed limit will be lowered to 35MPH in the active construction areas.
  • Jan. 18 – The contractor removed the concrete median, installed the temporary lanes and moved traffic. The contractor is now working on the storm drain system on both sides of the road.

Project Overview
East 120th Avenue will be widened from two lanes to three in each direction from Sylvia Drive, just east of Washington Street, to the N Line overpass, eliminating a bottleneck over that stretch. This is one of the busiest thoroughfares in Adams County; expansion is a necessity and long overdue.  

In addition, walking paths will be installed on both sides of the street and all traffic signals in the corridor will be upgraded.

Construction began Jan. 9 and is scheduled to last 12 to 18 months. Traffic will be narrowed down to one lane in each direction at times, depending on which area construction is taking place. Motorists are advised to use alternate routes when possible.    

Work will primarily take place from 7 a.m. to 6 p.m. on weekdays. However, special permission to work every day from 6 a.m. to 10 p.m. will be granted early on in the project and perhaps during other high-impact times. The extended hours are an effort to reduce the length of time the community will be affected by the most disruptive closures and construction.   

The city thanks you in advance for your patience, we understand a large road project is inconvenient. When finished, this stretch of East 120th Avenue will have 50% more capacity – reducing congestion and improving safety for everyone.



Inflation has affected every aspect of the economy, and construction is no different. The initial project cost estimate in January 2021 was $13.5 million; it is now $17.8 million. Federal funds are covering about $9.5 million, with the City of Thornton and Karl’s Farm developers contributing another $2.8 million. That leaves Northglenn spending $5.5 million, less than a third of the total project cost. 

Information from January 2021

The city plans to widen 120th Avenue to three lanes in both directions between Washington Street and York Street, plus install 8- to 10-foot pedestrian trails on both sides of the road. The project is tentatively scheduled to begin in April 2022.

There was a public meeting to hear about the project and ask questions on Jan. 20 at the recreation center. The meeting was recorded for others to view afterwards: 

What is the purpose of the project?
To widen 120th Avenue to three lanes in both directions between Washington  Street and York Street, as well as construct improved pedestrian trails on both sides of the road.

Why is the city investing in this project?
It will eliminate the bottleneck and congestion that occurs during high-volume traffic hours and improve road safety. Adding the third lane will increase capacity by 50%, is anticipated to reduce accident rates, and improve air quality (less idling ). A new traffic signal at Race Street will accommodate future development in the Karl’s Farm area.

How is the project funded?
The city received a federal grant in the amount of $9.48M, plus a private developer (Karl's Farm) provided $1.8M towards the local $3.98M of matching funds required.  In total, this is a $13.46M project (the city’s contribution is $2.18M, with $11.28M leveraged from other sources).

When will construction start and how long will it take?
The project timeline (subject to change) is to award the contract in April of 2022; the start date is not determined but hopes are it will be soon after the contractor is secured. It is a 12 to 14-month construction schedule.

Question from the info meeting -- was a noise survey conducted?
Yes, click here to see the report