Transport Decarbonisation Index (TDI): Methodology Brief

A robust methodology is essential for any effective composite indicator system. Similarly, a well-defined and user-friendly diagnostic toolkit is crucial for promoting the widespread, independent use of indexes such as the TDI. The TDI guides users in interpreting the resulting scores and accompanying policy recommendations, which are key to maximising the benefits of the index for all user groups.

This methodology brief provides a clear and comprehensive overview of the TDI methodology – from the selection criteria; to the normalisation, weighting and aggregation of the indicators; to the eventual provision of policy advice. The brief also details the main application approach of the TDI: combining the indicator assessment with policy guidance, the diagnostic toolkit and its functionalities.