2 Scenarios
Models are used to predict travel behavior given various scenarios of land use and transport capacity. Validation year scenarios are used to verify that model predictions are reasonable while future year scenarios are used to make planning decisions. The model package includes validation year, the MTP year, plus interim year scenarios.
The model comes with the validation year scenario folder included. Find it under the "scenarios" directory. Note that it includes both the highway and transit project lists.
To select it in the flowchart, use the scenario dropdown menu as shown below.
Once the scenario is selected in the TRMG2 drop down menu, check the input parameters as noted in section 6 below. Once confirmed, choose "Create Scenario."
This will build the scenario from the master files and include the appropriate transit routes and roadway projects. Note that this step is REQUIRED prior to running the model and must be run without error. If an error message is returned, after fixing the issue, rerun the "Create Scenario" step.
Custom scenarios can be created using the following steps.
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Create a folder in the "scenarios" directory and include the roadway and transit project lists with the appropriate project IDs.
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New scenarios can inherit parameters from other scenarios becoming child scenarios or be created as a new scenario. In the "Scenario Selection" dropdown, Select "Design or Edit Model" to create a new scenario that uses the master files or the scenario to inherit from.
For this example, we set up a new scenario without inheriting anything by highlighting "Design or Edit Model" first.
This will have the same parameters as the base year scenario, but importantly, any changes made to the base scenario's parameters will not affect the test scenario. For child scenarios, changes made to parent scenarios are inherited from the child scenario.
- From the "Add/Remove Scenario" menu item dropdown, choose the "Add a New Scenario" button
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Name the new scenario, accepting all other defaults, and click "OK".
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Click "OK" again to close the scenario dialog box.
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Check/modify common scenario input parameters:
Select the created scenario (e.g. test) from the scenario dropdown box and double click empty space in the flowchart to open the parameter editor, or select the "Modify Parameters" menu option.
Make sure that the Scenario Folder is pointing to the correct location. To change it, click on the folder icon on the right. In the pop-up, select the folder location in the "Value" section and browse to the correct folder location in the dropdown.
If se data alterations are involved in this scenario (e.g. you're running the 2050 scenario), right click in the model panel beside the flow chart, select "master files" and then "Master SE". Click the icon to the right of the file name to select the edited se_xxxx.bin input file. Note that this is the se_xxxx.bin file that will be copied to the scenario folder (_name) as "scenario_se.bin". The SE data file is located here:
Also, check the initial congested times file and ensure it is set to the correct year. Find this under Modify Parameters / Network Calculations / Speeds & Tolls. This will minimize model running time.
Other parameters are unlikely to be changed for most model applications. However, if you'd like to save turns for the AM/PM assignment, you can change the save turn flag to 1. Find this under Modify Parameters / Assignment
Many of the model's parameters are stored in CSV files to make viewing them in GitHub easier. The flowchart can be used to browse to those files or open them in TransCAD. Currently, CSV files cannot be edited in TransCAD, but this is under active development.
- From the TRMG2 menu, highlight the new scenario, and select "Create Scenario" from TRMG2 menu option. Note that this step is REQUIRED and must be run without error. If an error message is returned, after fixing the issue, rerun the "Create Scenario" step.
The scenario can be run using the green play arrow in the toolbar. This is the most common method. Alternatively, individual model steps can be run by right clicking them in the flowchart and choosing the relevant option under the "Run" context menu. Note that "Run Model to Here" will run the model to this step but will not run this step.