If a project authority is considering a project for constructing or improving a highway for which it is the highway authority, the project authority must, before details of the project are published, determine—
whether or not the project is of a type specified in Annex I or Annex II, and
if it considers the project is a relevant project of a type specified in Annex II, whether it should be made subject to an environmental impact assessment.
In this Part "project authority" means—
the Secretary of State,
the Welsh Ministers, or
a strategic highways company.
When making a determination under subsection (1)(b), a project authority must have regard to the following—
the information described in Annex II.A,
the selection criteria set out in Annex III,
any features of the project or measures envisaged to avoid or prevent what might otherwise be significant adverse effects on the environment, and
the results of any relevant environmental assessment which are reasonably available to the authority.
The project authority must make a determination under subsection (1)(b)—
as soon as possible, and
in any event within the period of 90 days beginning with the day on which it has access to the information mentioned in paragraphs (a), (c) and (d) of subsection (3).
If the project authority is satisfied that it is appropriate to do so by reason of exceptional circumstances relating to a project (including circumstances relating to the nature, complexity, location or size of project), it may extend the period specified in subsection (4)(b).