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Developing Bridge Failure Scenario
For the bridge failure scenario three main inputs were changed:
- Adding network updates to the inputs directory in the year the network change is to take place. Example, if a new network were to be introduced in the year 2016 an inputs/t26 folder would be created and the 2016 network would be placed in that directory, along with a [
globalTemplateUpdate.properties] file if a different version filename was used than the one coded in t0 and listed in the [globalTemplate.properties] file. - Updating the network in the version file (which is a copy of the file from
tlumip/root/scenario/inputs/t0) and placing it into the correct future folder. - Adjusting the tsteps.csv file as needed to have the transport model run in the desired years of network/skim changes
The first step is to create new tXX folder in the tlumip/root/scenario/inputs directory. If the year t26 (2016) is running it looks to t26 for a network. If no network exists in the t26 inputs folder (or if there is no t26 inputs folder, as is the case in the repo) than SWIM continues to look backward in time until it finds the latest network. in the case of the repo the only network provided is in the t0 folder at, tlumip/root/scenario/inputs/t0. Noting that this instruction set was created in March 2016, and within a year or so, the repo should be updated with future folders and years (such as a new network in t23 and t26 to represent known/current network changes).
Once the new folders are created, Visum version files from the t0 folder should be copied into those folders and then edited in the following step to represent the changes in the network.
Updating the Version File is as simple as opening the file in Visum and editing the link(s) of interest. In the case of a Bridge Failure, one could simply delete links. However for network comparability and for better documentation TPAU has found that it is better to simply restrict all access to the link as opposed to deleting it. In the case of a weight restriction (to heavy trucks), the link would simply be restricted to the "e" class, which is the class or mode that trucks use in SWIM. Personal cars use travels on class or mode "a". Transit travels on modes "b" (intercity bus), "i" (intercity bus), "l" (light rail), "m" (heavy rail - Amtrak), "r" (other heavy rail), "t" (intercity rail - should likely be deleted), "x" (express bus - BRT). There is also "n" for the air mode. If a user closes a road they will want to block the travel of all modes except air, which shouldn't be coded on a street link anyway.
For this example the Version file was copied from the t0 location to a new t21 location. That file was opened and edited such that the I-405 bridge across the Willamette was closed to all modes. The two links closed were from-to node pairs; 160081-154021 and 161026-153656. Another inputs folder was created for t22 (t23 for the 2 years closed scenario) and a t0 copy was placed in that location. This way the model starts with an intact network, has a bridge closer represented for x number of years, and then the bridge is fixed and the network is back to how it started. Note that in this case the network file name went unchanged. Being called "swimNetworkAttributes.ver" in each tXX folder. This is because the [globalTemplate.properties] file in t0 is step to point to this file name in all years. A user could apply a [globalTemplateUpdate.properties] file in t21 and t22 along with the new networks to change the file name, but this extra step was not taken in this scenario. Instead a readme was used to inform the user that the network is different in the t21 folder and quickly describe how the network is different, by identifying the two links that were closed.
The tsteps.csv file was altered in this scenario to run transport every year. This is a very simple file to edit. To change the modules that run a "1" simply added to the correct module and year. The table below shows how transport was turned on for every year between t20 and t32 (2022). This lets the model run for approximately 10 years after the bridge is repaired to see if the model returns to normal and how long it takes. The skims are re-generated every year so that the model can iterate back to normal year-by-year.
| Year | SI | NED | ALD | SPG1 | AA | SPG2 | PT | CT | TA | TR | PT - Logsums Only | SL - Generate Select Link Data | SL - Append Select Link To Trips | VIZ | MICROVIZ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 18 | i | ||||||||||||||
| 19 | 1 | 1 | i | i | 1 | i | i | i | i | i | i | ||||
| 20 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 21 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 22 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 23 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 24 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 25 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 26 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 27 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 28 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 29 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 30 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 31 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||
| 32 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
SWIM-TLUMIP Model User Guide, version 2.5
- SI - SWIM Inputs
- NED - New Economic Demographics
- ALD - Aggregate Land Development
- AA - Activity Allocation
- POPSIMSPG - PopulationSim Synthetic Population Generator
- PT - Person Transport
- CT - Commercial Transport
- TA - Traffic Assignment
- TR - Transit Assignment
- SL - Select Link
- SWIM VIZ - Reporting DB