Equal Time Maps for Transit Network (Isochrones) on QGIS

Question

I am on a committee looking to redesign transit service in Sacramento and need to be able to make equal-time maps or "isochrones," like the attached.

A prominent difference between transit isochrones and road isochrones:

1. each transfer has a temporal penalty. That is, it takes time to wait for the connecting bus.
2. that penalty is lower where the connecting routes are more frequent and higher where the connecting routes are less frequent.
3. some routes only serve stations, while others are considered to have an even distribution of stops along their routes.

( I am interested in a hybrid model between frequency and coverage that still creates a high-frequency grid between major traffic generators, but with routes that take different branches between the generators. This offers both frequency and coverage. Currently, the debate is binary, frequency or coverage.)

Answer 1

You should give OpenTripPlanner's Analyst functions a shot.

There is a tutorial that will get you started here

Answer 2

I'm not sure of the exact methodology used, but you might want to look at how Mapnificent was implemented (it's open source). This is based on the work done on Mapumental.

Here's the Sacramento one...

If you want to implement something like this yourself, you'll presumably need a dataset with timetables/transit times for transport nodes (in the UK this is called NaPTAN).