CTA - Chicago Transit Authority

Yellow Line Extension Project

Environmental Review


The National Environmental Policy Act requires evaluation of potential environmental impacts associated with federal projects and actions. For this project, the evaluation will be documented in an Environmental Impact Statement (EIS). An EIS will be prepared to identify impacts related to project construction and operation.

The EIS will include an evaluation of a No Build Alternative, a Transportation System Management Alternative and the Locally Preferred Alternative. The EIS will describe the alternatives, the existing environmental setting, the potential impacts from construction and operation of the alternatives, and proposed mitigation measures to reduce or eliminate potential impacts.

Scoping and Scoping Meetings
The process of determining the scope, focus and content of an EIS is known as “scoping.” Scoping meetings are an opportunity to obtain information from the public and governmental agencies. The scoping process asks agencies and interested parties to provide input on the proposed alternatives, the purpose and need for the project, the proposed topics of evaluation and potential effects and mitigation measures to be considered.

The input received during scoping is summarized in a Scoping Report, under Project Documents.

Alternatives Analysis Process

The purpose of the Alternatives Analysis (AA) Study, which ended in August 2009, was to examine a wide range of potential transportation options. In the AA Process, the project's purpose and need was identified, alternatives that meet the purpose and need were developed and evaluated, and comprehensive and ongoing public involvement was initiated. Many different transportation alternatives were identified in the AA Process. Based on public comment and an evaluation of those options against criteria that included cost, environmental factors and feasibility considerations, the number of options was narrowed. There were multiple screening stages and the results of each screening stage were presented at public meetings. At each stage, there was an opportunity for people to review and comment on the results. The end result of the AA Process was the selection of a Locally Preferred Alternative.

Environmental Impact Statement

The purpose of the Environmental Impact Statement is to study, in a public setting, the effects of the proposed project and its alternatives on the quality of the physical, human and natural environment. Areas to be evaluated for potential impacts from construction and operation of the proposed project include, but are not limited to:

The evaluation may reveal that the proposed project will not affect or affect substantially many of these areas.  Measures to avoid, minimize and mitigate potential adverse impacts will be identified and evaluated.

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