Public Transport Access Index (PTAI) – Buildings in Greater London

  • Created:
  • Reference: KBCN1149

For projects in Greater London, the Public Transport Access Index (PTAI) should be derived directly from the TfL WebCAT platform. When this tool is used, the BREEAM Tra 01/02 PTAI/AI calculation is not required.

Requirements:

  1. Baseline: Assessors must use the PTAL version that is current at the time the Transport Assessment is undertaken (Concept Design).
  2. Post-Construction Consistency: Once the design-stage PTAI is established, it does not need to be updated at the Post-Construction stage, even if the local transport network or WebCAT data has changed in the interim.
  3. Location: Access data via TfL WebCAT.
  4. Procedure: Follow the below technical guide to extract the specific Accessibility Index (AI) value from the WebCAT CSV export (Cell G3) for entry into the BREEAM Platform.

Locating-PTAI-via-TfL-WebCAT

04 03 2026 - Updated to clarify requirements and adding instruction for locating PTAI or AI via TfL WebCAT
03 08 2022 - Updated to clarify that the version used must be current at the time of the transport assessment, but this does not need to be updated at post-construction stage