Overview

The requirement to assess indirect and cumulative impacts of proposed federal actions was established in the Council on Environmental Quality (CEQ) regulations implementing the National Environmental Policy Act (NEPA).

¦ Indirect effects are caused by the project or plan, but are separated from direct effects by time and/or distance. Indirect effects include induced growth and related environmental impacts.

¦ Cumulative impacts are the aggregate result of the incremental direct and indirect effects of a project or plan, the effects of past and present actions, and effects of reasonably foreseeable future actions by others on resources of concern.

This Handbook focuses primarily on the assessment of indirect effects and cumulative impacts for individual transportation projects. This Handbook also briefly describes a range of approaches for using the statewide or metropolitan transportation planning process to address indirect effects and cumulative impacts for a region or corridor.

A consistent theme throughout this Handbook is the importance of maintaining a clear distinction between an indirect effects analysis and a cumulative impacts analysis. For that reason, those analyses are addressed separately in the Practical Tips section of the Handbook.