Transportation projects vary in type, size, complexity,
and potential to affect the environment. Transportation project effects can vary
from very minor to significant impacts on the human environment. To account for
the variability of project impacts,
and determine how compliance with NEPA is carried out and documented.
An environmental impact statement (EIS)
is prepared for projects where it
is known that the action will have a significant effect on the environment. The
following are examples of actions that normally require an EIS.