How do you develop a transportation demand model?

1 Define the purpose and scope

The first step is to define the purpose and scope of your model. What are the main questions you want to answer? What are the geographic and temporal boundaries of your analysis? What are the data sources and availability? What are the assumptions and limitations of your model? These factors will help you determine the type, level of detail, and complexity of your model.

2 Choose the model structure and components

The second step is to choose the model structure and components. There are different types of models, such as trip-based, activity-based, or agent-based, that represent travel behavior in different ways. You also need to decide what components your model will include, such as trip generation, trip distribution, mode choice, route choice, and network assignment. Each component has different methods, variables, and parameters that affect the model outcomes.

3 Collect and process the data

The third step is to collect and process the data for your model. You need data on the characteristics of the travelers, the transportation system, and the land use in your study area. You may use surveys, counts, sensors, GIS, or other sources to gather the data. You also need to process the data to make it consistent, reliable, and compatible with your model structure and components. You may need to aggregate, disaggregate, calibrate, or validate the data to ensure its quality and accuracy.

4 Run and calibrate the model

The fourth step is to run and calibrate the model. You need to input the data and parameters into your model and run it to generate the outputs. You also need to calibrate the model to make sure that the outputs match the observed or expected travel patterns. You may use statistical, graphical, or behavioral methods to compare the outputs with the data and adjust the parameters accordingly. You may also need to run sensitivity tests to check how the outputs change with different inputs or scenarios.

5 Analyze and interpret the results

The fifth step is to analyze and interpret the results of your model. You need to examine the outputs and evaluate how they answer your questions and meet your objectives. You also need to interpret the results in the context of your purpose and scope, as well as the assumptions and limitations of your model. You may use indicators, measures, or visualizations to summarize and communicate the results to your stakeholders.

6 Update and maintain the model

The sixth step is to update and maintain the model. You need to keep your model up to date with the changes in the data, the transportation system, and the travel behavior in your study area. You also need to maintain your model documentation, code, and files to ensure its usability and reproducibility. You may need to review, revise, or refine your model periodically to improve its performance and validity.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?