Draft Environmental Impact Statement (DEIS) & State Environmental Reports
Below are links to individual sections of the Draft Environmental Impact Statement (DEIS) and State Environmental Reports. The official comment period closed on Jan. 20, 2026. If you have any questions or comments after reviewing these materials, please share using the I-270 Study Feedback form.
The DEIS identifies a preliminary preferred alternative consisting of two general-purpose lanes and one new express lane that accommodates transit in each direction, replaces 12 aging bridges, rebuilds the Vasquez Boulevard Interchange, adds a new pedestrian overpass bridge, and improves the on and off movements at I-76.
Additionally, CDOT is committed to meeting community needs by incorporating numerous additional project elements, including aesthetic improvements, enhanced air quality monitoring, support for community and environmental projects, travel demand management, and workforce development.
Draft Environmental Impact Statement
- Front Covers and Table of Contents
- Executive Summary (English)
- Executive Summary (Spanish)
- Chapter 1 - Introduction
- Chapter 2 - Purpose and Need
- Chapter 3 - Alternatives Considered
- Chapter 4 - Environmental Analysis
- Chapter 5 - Preferred Alternative Mitigation Commitments
- Chapter 6 - Public and Agency Involvement
- Appendix A - Safety Assessment Technical Report
- Appendix B - Alternative Development Tech Report
- Appendix C - Alternatives Map Books
- Appendix D - Transit, Bicycle and Pedestrian Technical Report
- Appendix E1 - Transportation Impacts
- Appendix E2 - Traffic Technical Report
- Appendix E3 - Air Quality Technical Report
- Appendix E4 - Noise Technical Report
- Appendix E5 - Biological Resources Technical Report
- Appendix E6 - Wetland and Aquatics Technical Report
- Appendix E7 - Water Quality Technical Report
- Appendix E8 - Floodplains Technical Report
- Appendix E9 - Land Use Technical Report
- Appendix E10 - Social and Economics
- Appendix E11 - Modified Environmental Site Assessment Technical Report
- Appendix E12 - Soils and Geology Technical Report
- Appendix E13 - Historic Resources Technical Report
- Appendix E14 - Archaeological Resources Technical Report
- Appendix E15 - Paleontology Technical Report
- Appendix E16 - Recreational and Section 6(f) Technical Report
- Appendix E17 - Section 4(f) Resources Technical Report
- Appendix E18 - Visual Resources Technical Report
- Appendix E19 - Utilities Present Within The Study Area
- Appendix F - Public and Agency Involvement Technical Report
- Appendix G - References
- List of Preparers
State Environmental Reports
Meeting Boards
- I-270 Corridor Improvements Public Hearing Boards (English)
- Mejoras Del Corredor de la I-270 (Spanish)
