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​Indirect and Cumulative Effects

Assessment of Indirect and Cumulative Effects (ICE) is a requirement under the National Environmental Policy Act (NEPA) of 1969, as amended, and under the Council on Environmental Quality (CEQ) regulations implementing NEPA. ICE analysis is rooted in the environmental analysis performed as a natural part of the Transportation Development Process.

The NEPA class of action is determined based on the significance of impacts to the environment (natural, cultural, and/or human environment); therefore, the potential for each project's impacts must be identified. Impacts to the environment can be one of three types:

  • Direct Impacts: Impacts caused by the action
  • Indirect Impacts: Impacts caused by the action, but that are later in time or farther removed in distance but are still reasonably foreseeable
  • Cumulative Impacts: Impacts on the environment that result from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency or person undertakes such other actions