Environmental Study

The National Environmental Policy Act (NEPA) requires that the significance of a project’s environmental impact be evaluated. TxDOT is conducting an Environmental Assessment on the North and South projects, and an Environmental Impact Statement on the Central project.

Each project is undergoing rigorous environmental study, which evaluates impacts to the human and natural environment, including but not limited to, traffic noise, the community, natural resources, cultural resources and hazardous material sites.

To learn more, visit the Frequently Asked Questions page.

I-35 Capital Express North

Draft Environmental Assessment

An Environmental Assessment (EA) was prepared for the proposed project. A copy of the Draft EA and the supporting technical reports are available for public review on my35capex.com. The environmental study identified and assessed potential impacts due to the proposed project to the natural and human environment. View the Draft Environmental Assessment.

Technical Reports

In compliance with the National Environmental Policy Act, environmental technical reports were prepared to evaluate potential impacts to the human and natural environment.

View the Air Quality Assessment

View the Archeological Background Study

View the Biological Resources Documentation

View the Community Impact Assessment Report

View the Documentation of Public Meeting #1

View the Documentation of Public Meeting #2

View the Documentation of Public Meeting #3

View the Hazardous Materials Initial Site Assessment and Design Change Memo

View the Historic Resources Documentation

View the Indirect Effects Report 

View the Surface Water Analysis Form and Design Change Memo

View the Traffic Noise Analysis Report

I-35 Capital Express Central

The following draft documents are developed as part of the environmental review process. All of the documents are in draft form and will be revised based on the comments received.

Agency Coordination Plan

The Coordination Plan establishes a schedule and process for coordinating public and agency participation and comment during the environmental review process. View the Agency Coordination Plan

Purpose and Need Technical Report

The Purpose and Need Technical Report establishes the purpose and need for the project with supporting data and documentation. Final Purpose & Need Technical Report.

Range of Alternatives Technical Report

The Range of Alternatives Technical Report summarizes the alternatives that have been considered in previous efforts to improve I-35 and those that will continue to be considered as part of this environmental study. Final Range of Alternatives Technical Report

Alternatives Evaluation Criteria

The agency and public scoping process help to define the method that will be used to evaluate alternatives and identify the reasonable alternatives to be studied further. The alternatives evaluation process is based on evaluation criteria derived from the purpose and need for this project. View the Draft Alternatives Evaluation Criteria.

I-35 Capital Express South

Draft Environmental Assessment

An Environmental Assessment (EA) was prepared for the proposed project. A copy of the Draft EA and the supporting technical reports are available for public review on my35capex.com. The environmental study identified and assessed potential impacts due to the proposed project to the natural and human environment. View the Draft Environmental Assessment.

View the Center for Transportation Research (CTR) Traffic Safety Evaluation

View the CTR Operational Analysis 

View the CTR Environmental Justice Assessment

Technical Reports

In compliance with the National Environmental Policy Act, environmental technical reports were prepared to evaluate potential impacts to the human and natural environment.

View the Air Quality Assessment

View the Archeological Background Study

View the Biological Resources Report 

View the Community Impacts Report

View the Hazardous Materials Initial Site Assessment

View the Historic Resources Documentation

View the Traffic Noise Analysis Report

View the Water Resources Documentation

View the 2019 Public Meeting Documentation

View the 2020 Virtual Stakeholder Meeting Documentation