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OSSTIP/WPPTUA1- Developing a timetable for a higher-frequency and expanded SmartBus network
This is a Work Package as part of the OSSTIP project.
Inputs: PTUA's specification of which bus routes to improve, and what frequency to use. Working OSSTIP tools to allow sub-setting an existing GTFS network, and modifying the frequency of certain routes, to then create a new GTFS file (See OSSTIP/WP6.
Outputs: Created GTFS file of SmartBus routes with increased frequency. Modified original buses GTFS file, with the specified SmartBus routes removed.
Estimated Time: Small-Medium
As part of the PTUA Action-Case work in building OSSTIP, improving the smartbus network frequency was one of the negotiated targets to analyse and communicate as part of their network reform policy proposal.
Specifically, the bus networks to increase to 10-min or lower headway, during 6am-midnight, 7-days-a-week, are:
- existing smartbus routes: 703, 900, 901, 902, 903, 905, 906, 907, 908
- Note:- see below that in Feb 2015 we also decided to split the very long Smartbus routes 901, 902, 903 into subsets, similar to Transdev's announced plans for the routes.
- A secondary list of routes of interest:
223, 246, 250, 402, 410, 472, 600, 630, 828, 216, 219, 220, 552, 732.
- Note:- after a workshop in November 2014 showing the geometry of the updated routes in QGIS, at the PTUA's request we added some extra bus routes to the upgrade list, so it became routes:
- 216, 219, 220, 223, 232, 235, 246, 250, 270, 400, 402, 410, 411, 418, 420, 446, 447, 472, 494, 504, 508, 513, 552, 556, 561, 562, 600, 623, 630, 679, 693, 732, 733, 734, 737, 767, 781, 788, 791, 800, 822, 823, 824, 828, 841, 862
Initial work:- sub-setting initial GTFS bus network file into sections to upgrade
Much work was put into the OSSTIP/SimpleGTFSCreator package in late 2014 for extracting the 'abstract network topology and service' levels from an existing GTFS timetable, in order to support modification.
To simplify the task, I first added some GTFS sub-setting tools by Geometric region to reduce the number of relevant routes to process. By applying this using a polygon around "metro Melbourne", the area of interest for our network upgrades package, it reduced the number of bus routes in the GTFS from 681 (for all of Victoria) to 362.
The subsetting script in SimpleGTFSCreator is called subset_trips_by_route.py, and the resulting GTFS file in the OSSTIP_Common_LargeFile_Archives Dropbox is in the subpath:- GTFS/GTFS-ExtractedData-201406/melb-bus-gtfs-2014_06-metro.zip
I then wanted to extract just the bus routes specified for upgrading, to separate GTFS files, and then create a further GTFS file for the bus routes we weren't going to upgrade. The strategy here is that the smaller GTFS files of bus routes to upgrade could then be modified, while the remaining routes could be used as-is in calculations. This is because OpenTripPlanner has the nice feature of being able to combine an arbitrary number of GTFS files into a single 'graph' for routing analysis (as long as each GTFS file has separate trip, route etc IDs).
So with further use of the SimpleGTFSCreator subset_trips_by_route.py script, I created these new GTFS files as follows:-
- OSSTIP_Common_LargeFile_Archives/GTFS/GTFS-ExtractedData-201406/melb-bus-gtfs-2014_06-subsets/melb-bus-gtfs-2014_06-metro-smartbus.zip (9 routes)
- OSSTIP_Common_LargeFile_Archives/GTFS/GTFS-ExtractedData-201406/melb-bus-gtfs-2014_06-subsets/melb-bus-gtfs-2014_06-metro-upgrade_to_smartbus-v1-20141111.zip (14 routes)
- OSSTIP_Common_LargeFile_Archives/GTFS/GTFS-ExtractedData-201406/melb-bus-gtfs-2014_06-subsets/melb-bus-gtfs-2014_06-metro-non_smartbus_non_upgrade_to_smartbus-v1-20141111.zip (339 routes)
So the next stage was to extract the generalised network topology and service levels from the first of these two files, so we could modify them and create new upgraded versions.
Extraction process of generalised network topology and service levels
The next more challenging step in the process was to extract the topologies and service levels of each of the routes we wished to upgrade, in order to create a new GTFS file.
I had already worked-through the first version of this process in the simpler train network in OSSTIP/WPPTUA3.
However the bus routes present some challenges here, as several routes involve:-
- A complete loop in the route, between a start-point and end-point. This makes the network extraction more challenging.
- And/or deviations in the route (I.E. during different trips, sometimes a different version of the route is taken).
In order to add too much complexity to SimpleGTFSCreator, both of these issues are currently dealt with in a fairly simplified way:-
- Sections of bus routes that would cause an entire loop are currently skipped;
- We extract the 'longest path' through the entire route as the generalised route pattern :- based on a similar logic to the train network, to try and avoid express services.
Generally for the bus network these simplifications seemed to work satisfactorily, and we were able to extract both topologies (in the form of route stops, segments, and orderings of segment traversal on each route), and service performance in the form of speeds on segments at different times of day, and frequency of visiting each stop.
(Note 11th March 2015:- it would be good to return to the issue of allowing looped routes though, as this may be having a non-trivial impact on network performance in a couple of cases. It needs further analysis.)
Here are some exports from a QGIS project showing these routes, in the form of:-
- The existing train network as dark red-and-black lines;
- The smartbus network sections to upgrade as pink lines;
- The non-smartbus bus route sections to upgrade in yellow.
Revising for expanded route list
Workflow for creating upgraded frequency of routes and producing a new GTFS file
Issue with very long smartbus routes, and splitting of routes as a result
Issues with speed-extraction of buses from timetables
(Where output GTFS files are). (Include an estimate of bus numbers in peak hour before and after the upgrades ...)