Frequently Asked Questions (FAQs)

The project website contains information about the project background and development schedule. CDOT is dedicated to maintaining a transparent public involvement process and is conducting extensive public outreach efforts to gather input from corridor users and the diverse populations along the project area. Information about past and upcoming public involvement activities can be found under the Public Involvement tab on the webpage. 

The National Environmental Policy Act (NEPA) requires federal agencies to consider the environmental impacts of their decisions and consider all reasonable options or alternatives before deciding whether to move forward with a project. An Environmental Impact Statement (EIS) documents the need for the project, identifies potential alternatives to address the needs, describes the environment in the affected area, analyzes the benefits and effects of the project to the environment and community, and commits to measures to mitigate impacts of the project.
The Federal Highway Administration (FHWA) and the Colorado Department of Transportation (CDOT) are initiating an EIS to evaluate ways to improve the I-270 corridor. CDOT and FHWA began a NEPA process in 2020, initially anticipating an Environmental Assessment. Moving into 2023, CDOT determined a more detailed environmental review was needed and requested an EIS be prepared. CDOT recognizes that I-270 corridor improvements are necessary, and minimizing environmental and community impacts is important. CDOT and FHWA need input from residents and businesses in the area, highway and transit users, and other interested groups on how to improve the corridor and minimize negative impacts.

Improving the I-270 corridor is a priority for CDOT, FHWA, and local agencies. The I-270 corridor provides a key transportation link carrying more than 100,000 vehicles each day. It is a critical freight corridor for the region, with freight trucks making up nearly 10 percent of its daily traffic. Constructed between 1965 and 1970, I-270 no longer meets local and regional transportation demands. The interstate carries far more traffic than it was designed for, and travel delays are persistent. The pavement and bridges are stressed by the traffic loads, and emergency repairs to bridges and pavement are regularly needed. Crashes, emergency repairs, and planned maintenance require frequent closures of the highway, leading to slow and unpredictable travel times.
CDOT and FHWA are considering a range of alternatives to improve traffic flow and safety on the I-270 mainline highway, interchanges, and surrounding pedestrian and bicycle facilities. Preliminary alternatives under consideration are listed below and were developed with public and agency input through the early scoping process. The types of improvements considered in the alternatives developed include elements such as general-purpose lanes, managed lanes (Express Lanes), and transit-only lanes on the existing alignment; safety improvements such as wider shoulders and lengthened entrance or exit ramps; and bicycle and pedestrian improvements on existing, new, and adjacent alignment. 
  • No Action Alternative
  • Bicycle, Pedestrian and Transit Enhancements Alternative
  • Minimal Build Alternative
  • Three General-Purpose Lanes Alternative
  • Two General-Purpose Lanes and One Transit-Only Lane Alternative
  • Two General-Purpose Lanes and One Express Lane that Accommodates Transit
  • Three General-Purpose Lanes and One Express Lane that Accommodates Transit Alternative
  • Two General-Purpose Lanes and Two Express Lanes that Accommodate Transit

Express Lanes are new travel lanes built in addition to any existing general purpose lanes to provide drivers the choice of a more reliable trip by paying a toll or carpooling. Toll prices are set to manage traffic and have just the right number of vehicles in the lane to provide reliable, shorter travel time.

On some Express Lanes, tolls can change in price depending on the level of congestion. As traffic increases, the toll price goes up to make sure the lane always remains a free-flowing alternative for travelers. Conversely, the toll price will decrease when there is less traffic in the lane. Drivers will always be charged the amount on the overhead signage when they enter the Express Lanes.

For more information on Express Lanes, please visit

CDOT has identified eight bridges that are in critical need of replacement. These bridges are within the I-270 improvement area. Bridge replacement designs are being developed in conjunction with the broader environmental study. CDOT is advancing the design of these critical bridges to accelerate their replacement as the broader corridor improvements are defined and approved. Bridge maintenance and emergency repairs will continue throughout the environmental study process.
I-270 and other features such as railroads and streams bisect the surrounding area and are a barrier to movement within and around neighborhoods, businesses, and industrial areas in the project area. CDOT and FHWA are evaluating potential ways to facilitate better east-west movement across I-270 and increase bicycle, pedestrian, and transit connections. CDOT has met with bicycle users and community members to identify needs and constraints and is developing specific improvement options.
The Flatiron Flyer 5 is the only service that currently uses I-270. It operates in peak periods between Boulder and Fitzsimmons Medical Center and does not stop within the corridor.
Transportation demand management, traffic demand management, or travel demand management are terms for policies or approaches that increase capacity by reducing or redistributing travel demand, such as encouraging carpooling or incentivizing travel in off- peak periods, without significant capital investment. Travel demand management strategies will be considered and included in all of the action alternatives.
DRCOG’s 2023 and 2050 regional travel demand models are being used for the I-270 transportation analysis. To date, the I-270 team has calibrated the 2023 regional travel demand model using traffic demand data collected in May 2023. They have initiated calibration of a microsimulation model to evaluate I-270 improvement alternatives. The model is used to estimate future demand, travel speeds, impacts of congestion, and resulting travel reliability along I-270 and at the I-270 interchanges under different improvement alternatives. The model also projects shifts in traffic volumes as capacity is added to the network to measure induced demand.
In addition to federal environmental justice and air quality requirements that have been in place for many years, CDOT has additional considerations under Colorado Senate Bill (SB) 21-260, Sustainability of the Transportation System. The requirements of SB 21-260 apply to regionally significant transportation capacity projects like I-270. The bill, signed by Governor Polis in 2021, requires CDOT to assess, work with, and evaluate impacts to communities the state has identified as Disproportionately Impacted (DI), meaning these areas have large communities of color, are lower income, have higher housing cost burdens, and are at risk of experiencing higher levels of health or environmental impacts. Mapping from the Colorado Department of Public Health and Environment identifies DI Communities in most of the project area. The EIS will comply with both state and federal requirements related to DI communities and environmental justice. SB 21-260 also includes new requirements for air quality modeling, monitoring, and mitigation beyond what is required under NEPA. Additionally, it establishes a new Greenhouse Gas (GHG) Standard for transportation plans. The new standard requires CDOT and the state’s five metropolitan planning agencies to create transportation plans that provide more travel choices, to reduce GHGs and to set reduction levels. The agencies must use sophisticated travel models to make this determination and if an agency can’t meet the GHG reduction levels, additional mitigation is needed to meet the standard.
Cumulative impacts can result from minor actions that occur in a project area over time and from a variety of activities that when taken together can have serious impacts. The I-270 EIS will include a cumulative impact analysis to evaluate the impacts of the project individually but also in relation to other past, present, and reasonably foreseeable actions in the vicinity and/or region.

There is a lot of right of way (land owned by CDOT for the highway) in the I-270 corridor, and CDOT does not anticipate direct impacts to Sand Creek or other surface waters.

CDOT and FHWA have been engaging residents and businesses over the past three years and are planning an extensive outreach program for the EIS that is expected to employ various methods, such as public meetings, bus tours, stakeholder meetings, elected official meetings, and agency meetings. We plan to host and attend community events and meetings to develop community alliances and agency partnerships to share information and gather feedback. Information will be shared through many channels, such as in-person meetings, online meetings, telephone town halls, and through website, email, and printed and video materials.

CDOT will be out in the community throughout the environmental study process, listening to ideas for the corridor. After the initial “scoping” phase where CDOT and FHWA are collecting and reviewing data, coordinating with other agencies and interest groups, and seeking public input, the next phases include developing and evaluating alternatives, analyzing traffic and environmental data, and preparing a draft report. The information will be presented in a draft EIS, which will identify the preferred alternative for the project, present the environmental analysis, and identify and commit to mitigation measures to avoid or lessen community and environmental impacts.  The public will have an opportunity to review and comment on the draft EIS before a final EIS and record of decision (ROD) are published. The ROD notifies the public of the decision made and presents the reasons for that decision. Each step in this process involves coordination with stakeholders, the public, and state and federal agencies. After completing the environmental study, CDOT would design and implement I-270 corridor improvements, prioritizing replacement of the bridges that are in critically poor condition as a first phase.

There are many ways to provide input throughout the environmental review process. You can:

  • Attend a public meeting to fill out a comment form and talk to project representatives.
  • Visit the project website to stay up to date on the latest progress and events ( and provide input via the comment form.
  • Leave a message or request information on the project hotline (303-512-4270).
  • Email or mail the project team at: [email protected] or CDOT Region 1, 2829 Howard Place, Denver, 80204.

The best ways to stay informed are to visit; attend future public events and meetings; request project presentations, updates or tours; send us an email at [email protected]; call the project hotline at 303-512-4270; and/or subscribe to the project email list to receive project updates and information about public meetings. The project team and CDOT’s Bilingual Community Liaison will be out in the community throughout the study process to listen to your ideas for the corridor and your community.