Public Transport Accessibility Level (https://tfl.gov.uk/info-for/urban-planning-and-construction/planning-with-webcat/webcat) is a calculated method that uses the distance from any point to the nearest public transport stop, and service frequency at those stops. The result is a grade from 1–6 where PTAL 1 indicates very poor access by public transport, and PTAL 6 indicates excellent access by public transport.
PTAL is one factor in determining the density range for a new development.
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