The National Environmental Policy Act of 1969 (NEPA) is the basic national charter for the protection of the environment. NEPA requires that a detailed analysis be prepared if any federal agency is undertaking a major federal action significantly affecting the quality of the human environment. The study must include information regarding potential impacts to the environment that may results from the proposed action and any adverse effects that cannot be avoided if the proposed action is implemented. The study must also include an analysis of possible alternatives to the proposed action and information regarding indirect and cumulative impacts. The final study helps provide agency personnel and other decision makers with the best possible information so that they can make an informed decision regarding the relative merits and detriments of a proposed action. The major components of the NEPA process are as follows:


  • Purpose and Need
  • Alternatives
  • Impacts
  • Mitigation
  • Public Involvement
  • Agency Coordination


Since the last Public Information Meeting held in June 2018, the project team, in coordination with SCDOT, FHWA and FRA, has been working on developing alternatives for the Assembly Street Railroad Separation Project. Comments received during the first Public Information Meeting and Stakeholder Meetings have been considered during the development of alternatives.

Alternatives Analysis: Development and Screening

The first step is to prepare initial transportation options or the range of alternatives (many general in nature). These are being developed based upon past alternatives and studies, stakeholder and public input/recommendations and agency input.

Level 1 Screening: The Level 1 Screening will evaluate the range of alternatives to determine if it meets the primary purpose and need as well as minimum design criteria.

The range of alternatives that meet the primary purpose and need, as well as minimum design criteria, will be advanced as preliminary alternatives and evaluated under the Level 2 Screening.

Level 2 Screening: The Level 2 Screening will evaluate which of the preliminary alternatives (from the Level 1 Screening) best meet the primary purpose and need, while also considering the degree to which these alternatives meet the secondary purpose and need, their impacts to the natural and human environment, estimate project costs, logical considerations and overall feasibility. Only the alternatives that meet these criteria will be advanced for consideration as Reasonable Alternatives.

The alternatives that are not eliminated through the Level 2 Screening process will be further refined through preliminary engineering before detailed impact analyses begin for the environmental assessment. The preliminary design for roadway will include details such as number of lanes, horizontal and vertical alignments, typical sections, right of way limits, intersection layouts and construction limits. Preliminary track design will include similar details as listed above as well as interlocking and control point layouts, railroad structure and retaining wall locations, and at-grade crossing improvements.

Each reasonable alternative will be designed to a similar level of detail. Once the preliminary design work is complete, the potential effects of the alternatives will be identified and compared at an equal level of detail as required under NEPA. The reasonable alternatives will be detailed in the Environmental Assessment with the ultimate goal of selecting a Preferred Alternative that would meet the overall purpose and need of the project.

Alternatives Process

Environmental Videos

NEPA Decision-Making

NEPA's Role