(I-405 to I-5) Improvement Project

The California Department of Transportation (Caltrans) District 12, in cooperation with the Orange County Transportation Authority (OCTA), proposes to widen State Route 55 (SR-55) in both directions from just north of the Interstate 405 (I-405)/SR-55 Interchange to just south of the Interstate 5 (I-5)/SR-55 Interchange between Post Miles 6.4 and 10.3, traversing the cities of Santa Ana, Tustin, and Irvine in Orange County, California. The project purpose is to reduce traffic congestion and improve mobility and traffic operations in the project study area.

An Inital Study/Environmental Assessment (IS/EA) - Mitigated Negative Declaration(MND)/Finding of No Significant Impact (FONSI) has been prepared for this project and provides responses to Draft IS/EA and Supplemental IS/EA comments received during both public circulation periods. It also compares the environmental impact evaluation and proposed avoidance, minimization and/or mitigation of potential impacts associated with all proposed Build Alternatives; and identifies the Preferred Alternative - Build Alternative 3 Modified (Alternative 3M).

Anticipated Schedule:
PA&ED – Present until Fall 2017
Design – Fall 2017 to Summer 2020
Construction – Winter 2021 to Fall 2024

Initial Study with Mitigated Negative Declaration/Environmental Assessment with Finding of No Significant Impact

Cover page/General Information/Title Page
Mitigated Negative Declaration
Finding of No Significant Impact
Table of Contents
Chapter 1 – Proposed Project
Chapter 2 - Affected Environment, Environmental Consequences, and Avoidance,
Minimization, and/or Mitigation Measures

2.1 Land Use
2.2 Growth
2.3 Community Impacts
2.4 Utilities and Emergency Services
2.5 Traffic and Transportation/Pedestrian and Bicycle Facilities
2.6 Visual/Aesthetics
2.7 Cultural Resources
2.8 Hydrology and Floodplain
2.9 Water Quality and Storm Water Runoff
2.10 Geology/Soils/Seismic/Topography
2.11 Paleontology
2.12 Hazardous Waste/Materials
2.13 Air Quality
2.14 Noise
2.15 Wetlands and Other Waters
2.16 Plant Species
2.17 Animal Species
2.18 Invasive Species
2.19 Cumulative Impacts
2.20 Climate Change
Chapter 3 – Comments and Coordination
Chapter 4 – List of Preparers
Chapter 5 - Distribution List
List of Appendices
Appendix A – CEQA Checklist
Appendix B – Resources Evaluated Relative to Requirements of Section 4(f)
Appendix C – Title VI Policy Statement
Appendix D – Summary of Relocation Benefits
Appendix E – Environmental Commitments Record
Appendix F – List of Technical Studies
Appendix G – FEMA FIRM
Appendix H – Response to Comments

Project Report

If you have any questions about the MND/FONSI, please contact Charles Baker, Senior Environmental Planner, California Department of Transportation, District 12, Environmental Analysis- Specialist Branch, 1750 East 4th Street, Santa Ana, CA 92705 or via e-mail to:


For reference, the link to the previously circulated Draft IS/EA is provided below:

Draft Inital Study/Environmental Assessment (November 2015)

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