Guidance

Common analytical scenarios databook

A selection of data tables, published alongside the TAG uncertainty toolkit, to help consider and model the common analytical scenarios.

• From: Department for Transport
• Published: 8 August 2022
• Last updated: 28 November 2024 — See all updates

Documents

Common analytical scenarios databook

ODS, 2.52 MB

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Common analytical scenarios databook, including forthcoming changes for May 2025

ODS, 2.52 MB

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Forthcoming change: base year update

https://www.gov.uk/government/publications/tag-forthcoming-changes/forthcoming-change-base-year-update

Details

Detailed assumptions and inputs for modelling the common analytical scenarios (CAS) outlined within the Department for Transport’s TAG uncertainty toolkit.

The CAS databook scenario grid (SG) explains the assumptions in each scenario. It supplements the TAG databook, which should be used for all values pertaining to the core scenario.

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.

Published 8 August 2022
Last updated 28 November 2024 + show all updates

1. 28 November 2024

   Updated with forthcoming changes for May 2025.

2. 17 November 2023

   Error correction: correction to the values of time for the technology scenario.

3. 31 May 2023

   Updates made to marginal external costs, car costs and car and bus journey times.

4. 24 August 2022

   Corrected an error in the fuel efficiencies for the Mode-balanced Decarbonisation scenario.

5. 8 August 2022

   First published.