Uses of Travel Demand Models Beyond the MTP Janie Temple Transportation Planning and Programming Division October 12, 2011
Presentation Outline What is a Travel Demand Model? Cautionary notes on using models Typical Uses Emerging Uses Innovative Uses
What are Travel Demand Models Travel demand models (TDMs) are developed to simulate actual travel patterns and existing demand conditions in an urban area or region.
Travel Demand Modeling Forecasts are used to develop information to evaluate the effects that known and projected changes in socioeconomic conditions may have on the demand for travel on the urban area's major roadway and transit systems.
The Travel Demand Modeling Process Trip generation Trip Distribution Mode Choice Traffic Assignment
Notes on using TDMs - Application Consistency Model construct must be consistent with The requirements of the analysis. For example, sketch planning models are appropriate for analyses to evaluate and select specific transportation alternatives for further analysis but would be inconsistent with the analysis requirements for estimating toll revenue.
Application Consistency Consistency between model framework and analysis requirements is necessary to ensure that the model is not used in a way that is inconsistent with the theory on which it is founded.
Notes on using TDMs - Reasonableness Checks Reasonableness checks should be part of model development and analyses standard practice because there are many opportunities for introducing erroneous data, omitting information, or misunderstanding models and analyses.
Reasonableness Checks Input data Calibration/Validation data Evaluate each model step results Evaluate final model results Sensitivity testing
Notes on using TDMs - Benefits Known input and analysis parameters Allows comparison of alternatives Baseline and alternatives can be easily compared Results can be replicated Results can be compared to other data sources such as Census data
Typical Uses of TDMs TDM output is used by TxDOT, MPOs, and local governments to: Develop or update the metropolitan transportation plan Program projects for additional study Rank projects for the Transportation Improvement Program Emissions analysis in non-attainment areas
Typical Uses of TDMs Evaluate system improvements Identify system deficiencies Conduct Alternative analysis Supports future design level traffic development
Typical Uses of TDMs GIS Databases The model input data consists of three primary databases for both base and forecast years. Network database Traffic analysis zone database Demographic database
Using TDM Database Road Network in Tyler, Texas
Using TDM Databases Employment in Tyler, Texas
Using TDM Results Travel Patterns in Tyler, Texas
Using TDM Results Volume to Capacity Ratios in Tyler, Texas
Emerging Uses of TDMs Linking planning and environmental Traffic operations analyses HOV Analysis Toll and HOT analyses Transit analyses New/Small Starts Applications Needs based analyses TMMP/TUMP
Planning and Environmental TDMs may be used for planning and environmental linkages: Statewide Implementation Plan development Conformity emissions analyses Air quality studies and analyses TCM evaluations Hot spot analyses Mobile Source Air Toxics analyses
Planning and Environmental Indirect and cumulative impact (ICI) studies - used at least as baseline Socioeconomic analyses (demographics and land use) - used at least as baseline Regional toll analyses
Planning and Environmental Alternatives analyses (traffic redirection studies) Land use information may also be used to help assess water quality and biological impacts Need and purpose
Operational Analysis TDMs Macro scale Regional travel patterns 24 hr/daily demand Typical weekday travel Simplified network Link volume output Simulation Models Micro scale Addresses dynamic aspects of traffic Incremental demand Detailed network Capacity restrained Provides network delay
Operational Analysis TDM and simulation models are used together to accomplish operational Analysis. Simulation model inputs include: The regional TDM Local travel survey data
Innovative Uses of TDMs Evaluate alternate growth scenarios Evaluate major transit projects Evaluate major land use changes Link to land use models Link to economic models Link to the Statewide Analysis Model Link to other freight or truck models
Innovative Uses of TDMs Commuter rail studies using planning models and the Statewide Analysis Model Evaluate hurricane evacuations Evaluate impacts of floods Evaluate smart growth impacts Evaluate alternate funding scenarios
Conclusions Travel demand models are powerful tools Travel demand models can be utilized in transportation planning in innovative ways Understanding the model is critical to producing effective analyses
If you need additional information For questions about the development or uses of the travel demand model, please contact one of the following people:
Contact Information Janie Temple (512) 486-5107 jtempl1@dot.state.tx.us Greg Lancaster (512) 486-5126 glancas@dot.state.tx.us