Alamo Area Metropolitan Planning Organization
We plan to keep you moving!

Travel Demand Modeling (TDM)


The Alamo Area Metropolitan Planning Organization develops and maintains a full set of Travel Demand Models (TDM) for our region, covering all of five counties, including Bexar, Comal, Guadalupe, Kendall and Wilson. The current TDM, known as San Antonio Multi-modal Model, version 4.1 (SAMM4.1 runs in TransCAD 8.0) is currently being updated (to SAMM5.0) for better suitability in analyzing the air quality implications for various roadway and transit projects and more flexible options for forecasting traffic on HOV lanes. SAMM5.0 will be used for evaluating alternative demographic scenarios as well as alternative highway and transit systems as part of the Metropolitan Transportation Plan (MTP) (Mobility 2050) update, that is currently in progress. AAMPO’s TDM is a traditional 4-step model including Trip Generation (Tripcal6), Trip Distribution (Destination Choice), Mode Choice (Nested Logit) and Traffic Assignment (TransCAD MMMC User Equilibrium). The SAMM 5.0 models feature Speed Feedback and provide time-of-day forecasts for 4 daily time periods, including AM-Peak, Midday, PM-Peak & Overnight.  

Our Travel Demand Models provide the primary means for identifying existing and future transportation system deficiencies and for assessing proposed regional mobility improvements. The models are suitable for the following applications:

The new SAMM5.0 TDM is being calibrated and validated to new travel data (including 2020 pre-CV19 traffic counts & transit ridership, as well as 2018-2019 travel surveys: Workplace, Commercial Truck, External, Airport & Special Traffic Generators), with a Short-Range Forecast for 2030, a Mid-Range Forecast for 2040 and a Long-Range (MTP) Forecast for 2050. Intermediate forecasts are also available for 2025, 2035 & 2045. The AAMPO Transportation Policy Board is scheduled to vote on approval of the Mobility 2050 Plan in May of 2022.

Please select a category of interest to you:

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If you have any questions or comments, please contact:

Zachary Graham

Senior Transportation Modeler
Travel Demand Modeling Supervisor

(210) 230-6907