Guidance

TAG unit A3 environmental impact appraisal

Guidance on the analysis of environmental impacts in transport appraisals.

Documents

TAG unit A3 environmental impact appraisal, including forthcoming changes for May 2025

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Forthcoming change: base year update

Details

This document gives guidance on environmental impact appraisal.

The previous version of this guidance was published in November 2023.

TAG provides information on the role of transport modelling and appraisal, and how the transport appraisal process supports the development of investment decisions to support a business case.

Updates to this page

Published 31 May 2019
Last updated 28 November 2024 + show all updates
  1. Updated with forthcoming changes for May 2025.

  2. TAG unit A3 updated.

  3. Forthcoming changes added.

  4. TAG unit A3 guidance updated.

  5. Added forthcoming change about appraisal guidance updates.

  6. Added forthcoming change about carbon valuation.

  7. TAG unit A3 guidance updated.

  8. Added forthcoming change: spring 2023 data book and guidance updates

  9. Unit A3 guidance updated.

  10. Forthcoming change to guidance note added, the note details guidance alterations to be implemented in May 2022.

  11. Updated with new version of unit A3 guidance.

  12. Updated TAG unit A3 guidance.

  13. NO2 changed back to NOx in 3.2.7 following Department for Environment, Food & Rural Affairs clarification.

  14. Information updated for technical errors NOx changed from NO2 in 3.2.7 and 3.4.4.

  15. First published.

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