(In the literature they use “accessibility” which to me is talking about things like level boarding)
TIL about the PTAL metric, which is fundamentally derived from walk time + wait time from the point of interest to every stop within a certain radius.
This then can be turned into an “equivalent doorstop frequency” and aggregated across nearby stops for an index.
TFL have a handy map. I’ve also attached their main document about it.
In the doc, TfL also define more metrics:
The TIM (full zone / travel time only) and CAPITAL (finer grained including walk time) models for measuring travel time from anywhere to anywhere
The Access to Opportunities and Services metrics which measure travel time by PT or walking for each of employment, education, GPs, food and green space (this is banded by standard deviations). But apparently a lot of what it shows is just density level.
Catchment Analysis looks at everything which is within 45 or 60 minutes of a certain place and asks how that changes with e.g. a new route or station or frequency upgrade.
(Jarrett Walker & associates also like to prepare maps showing how many jobs are accessible via PT from each suburb before and after a proposed route redesign.)
Thanks for this.
I really like the concept of isochrones - zones where you can get to in 10, 15, 30, 45 min.
This is a mode and technology neutral concept and really shows what we want directly - access.