Guidance

Vehicle emissions carbon tool (VECAT)

Vehicle emissions carbon tool to quantify road user carbon emissions for scheme appraisal.

• From: Department for Transport
• Published: 16 October 2025

Documents

Vehicle emissions carbon tool (VECAT)

4.48 MB

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Vehicle emissions carbon tool user guide

PDF, 1.1 MB, 45 pages

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Details

The vehicle emissions carbon tool (VECAT) allows transport practitioners to quantify road-user carbon emissions.

You can use it to:

• annualise road-user emissions and calculate emissions over a set appraisal period
• estimate the long-term carbon impact of a transport scheme as part of a business case

The tool works on a link-by-link basis using the parameters and formulas from DfT’s Transport analysis guidance (TAG) and the TAG data book.

Read the user guidance on this page and download the Excel spreadsheet to use the tool.

Published 16 October 2025