Asphalt Pavement Embodied Carbon Tool

asPECT provides a methodology to calculate the life cycle greenhouse gas emissions or ‘carbon footprint’ of asphalt used in highways

This website provides access to the asPECT software that was developed as a result of Collaborative Research Programmes undertaken between 2008 and 2014. The Collaborative research is a joint initiative of Highways England, Mineral Products Association, and Eurobitume UK. A review of the asPECT tool was undertaken in 2020. As part of the review, the constants used throughout asPECT were reviewed and where a newer, more applicable data source existed, the values have been updated.

The Publicly Available Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Services (PAS 2050) has been followed in writing these documents.

The project deliverables are available here.


Documentation consists of a protocol (v4.2) and accompanying further guidance document (v4.2) which specify how to calculate the GHG emissions associated with asphalt and its use in highway applications. There is also an asPECT user manual (v2.1).

asPECT Guidance v4.2

asPECT Protocol v4.2 

asPECT User Manual v2.1

The latest review of asPECT, including the updating of the constants, is reported in:

PPR960 Review and update of the asPECT carbon footprinting tool for asphalt road pavements

Calculator Tool 

A downloadable spreadsheet-based calculator guides the user through the methodology of the protocol and makes the necessary calculations using up-to-date emissions factors on the user’s behalf. 

This tool is available free of charge, but we ask that you provide your contact details using this form so that we can let you know when the Constants file is updated. This will ensure you are making your calculations based on the latest available template. Your request for the tool will be shared by TRL with the tool owners/managers: National Highways, Eurobitume, and the Mineral Products Association.





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