Overview This Handbook is intended to provide practitioners with practical suggestions for defining the purpose and need and determining the range of alternatives for highway@ public transportation@ and railroad projects. The adoption of the purpose and need statement is one of the most consequential decisions that the lead agencies make in the National Environmental Policy Act (NEPA) process@ because the purpose and need provides the foundation for determining which alternatives will be considered and for selecting the preferred alternative. The purpose and need also can be a major factor in deciding whether a particular alternative can be approved under other laws such as Section 4(f) of the U.S. Department of Transportation (U.S. DOT) Act and Section 404 of the Clean Water Act. Because of its importance@ the decision on purpose and need can become a source of disagreement and delay in the NEPA process and is frequently a focal point for litigation. This Handbook summarizes key requirements and provides suggestions about how to develop a purpose and need statement that is clear@ well-supported@ and defensible. Alternatives screening also plays an enormously important role in the NEPA process@ because it is the vehicle for deciding which alternatives remain on the table for detailed environmental analysis. Typically@ a screening process involves identifying a broad range of potential alternatives and then applying a standard set of evaluation criteria to eliminate alternatives that do not meet the purpose and need or are otherwise found to be unreasonable. In addition@ when the number of reasonable alternatives is very large@ similar alternatives may be combined to allow for a manageable number of alternatives to be studied in detail. Disagreements about which alternatives to eliminate from consideration can become a significant source of delay in the NEPA process@ and litigation challenges often focus on the adequacy of an agency??s rationale for its screening decisions. This Handbook provides an overview of the legal requirements for alternatives screening and provides suggestions for managing this process effectively. The topics covered in this Handbook include: ? Considering relevant legislation and transportation planning decisions ? Determining and documenting the need for the project ? Defining the project purpose ? Developing and applying alternatives screening criteria and ? Coordinating with agencies and involving the public