Inputs

TDM23 is a file-based model where the inputs are visible in the user interface (UI). These inputs are also stored in the "CTPS_TDM23.parameters" and "CTPS_TDM23.scenarios" files. For more information, refer to the Define Scenarios section. The inputs can be either references to files, such as zonal data and networks, or simple values.

Input Folder Structure

Folder	Description
zonal	Socioeconomic and geographic data
zonal/shp	TAZ shapefiles
zonal/equity	Equity component data
networks/tdm23.1.0/[scenario_year]	Roadway and transit network
networks/osm_20220506	Non-motorized network
params	General parameters for model components
params/airquality	Parameters for air quality component

The TDM23 UI organizes frequently changed parameters in the "Primary Inputs" section, making it easy for the modeler to adjust values that are likely to vary from scenario to scenario. Less frequently changed inputs, such as parameter values, are organized by demand and supply components. This structure helps prevent accidental changes or missed settings while maintaining full functionality. The tables below present only the data that can be found in the "Primary Inputs" section of the UI. For a full list of all files and parameters in TDM23, please refer to the Data Dictionary.

Zonal Data

The zonal data input is data organized by TAZ or Census Block.

Zonal Data

Type	Description	Primary Inputs Location in UI	Data Dictionary
MA Population	Population in Massachusetts from UrbanSim	Socio-Economic and Trips	MA Population
NH and RI Population	Population in New Hampshire and Rhode Island from PopulationSim	Socio-Economic and Trips	NHRI Population
MA Employment	Employment in Massachusetts from UrbanSim	Socio-Economic and Trips	MA Employment
NH and RI Employment	Employment in New Hampshire and Rhode Island from PopulationSim	Socio-Economic and Trips	NHRI Employment
School and University Enrollment	K-12 and College Commuter	Socio-Economic and Trips	School and University Enrollment
Intersection Densities	Proxy for ease of walking and biking	Networks and Zonal Data	Intersection Densities
Parking Costs	Hourly, daily and monthly	Networks and Zonal Data	Parking Costs

Note

The population and employment data are at the block level. However, TAZs and blocks don't line up perfectly, so a single block can be part of multiple TAZs. Two files explain how blocks and TAZs are related:

block_allocation_20230314.csv: Located in zonal/shp/, this file lists all the TAZs that each block overlaps and the area ratio of the block within each TAZ. Since a block can be part of multiple TAZs, the file has more rows than there are blocks, with each block appearing multiple times to show its different TAZs and corresponding area ratios.
block_assignment_20230314.csv: Also located in zonal/shp/, this file, along with the database tables, clearly links each TAZ to a block based on the block's largest area within the TAZ.

Networks

Roadway Symbol

Roadway

Facility Types

Facility Type	Definition
Freeways	Grade separated, high speed, high capacity and limited access
Expressways	Very few signals, high speed connections between major points
Major Arterials	Connecting major points with frequency traffic signals
Minor Arterials	Connecting local points and major arterials with frequency traffic signals
Collectors	Connecting to neighborhoods and arterials
Local Roads	lower speed connectors
Ramps	Connecting freeways and expressways to other roads

Roadway Network Data

Type	Description	Primary Inputs Location in UI	Data Dictionary
Roadway DBD File	Roadway links and nodes	Networks and Zonal Data	Roadway DBD File
Turn Penalties	Delay for turning movements	Networks and Zonal Data	Turn Penalties
Init Speeds - am	Warm up speeds for AM	Networks and Zonal Data	Init Speeds - am
Init Speeds - md	Warm up speeds for MD	Networks and Zonal Data	Init Speeds - md

Transit Symbol

Transit

The transit network represents the alignment, stop locations, headways, travel times, and fares for transit service aggregated to the four model time periods. It is developed using General Transit Feed Specification (GTFS) data.

Transit Modes

Transit Mode	Description
Local Bus	MBTA bus service
Express Bus	MBTA express bus service (higher fare, express service)
Bus Rapid	Silver Line - all routes
Light Rail	Green Line and Mattapan High Speed
Heavy Rail	Red, Blue, and Orange Lines
Commuter Rail	All commuter rail lines
Ferry	All commuter boat services
Shuttle	Point to point service, potentially restricted access
RTA Local Bus	Bus services supplied by non-MBTA operators
Regional Bus	Bus services with longer distance routes

Transit Network Data

Type	Description	Primary Inputs Location in UI	Data Dictionary
Transit RTS File	Transit links and nodes	Networks and Zonal Data	Transit RTS File
Transit Mode Table	Mode attributes	Networks and Zonal Data	Transit Mode Table
Init PnR Demand - am	Warm up PnR demand	Networks and Zonal Data	Init PnR Demand - am

Non-motorized Symbol

Non-motorized

The non-motorized network is created from OpenStreetMap excluding links where walking and biking is prohibited. It includes all local roads and paths unlike the roadway network.

Non-motorized Network Data

Type	Description	Primary Inputs Location in UI	Data Dictionary
Non-Motorized DBD File	Walking and biking network	Networks and Zonal Data	Non-Motorized DBD File

Others

TDM23 incorporates other variables related to model components such as:

Other Data

Type	Description	Primary Inputs Location in UI	Data Dictionary
Special Generators	Casinos	Socio-Economic and Trips	Special Generators
Base External Station Volumes	External trips	Socio-Economic and Trips	Base External Station Volumes
Airport Ground Access Trips	Airport Trips	Socio - Economic and Trips	* Simple value