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Agenda. Overview Why TransCAD Challenges/tips Initiatives Applications. Overview. Transportation planning and policy guidance 3 C process Planning tools Travel demand modeling Project level forecasts. Role of Statewide Planning. Organizational Structure.

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Presentation Transcript
  • Overview
  • Why TransCAD
  • Challenges/tips
  • Initiatives
  • Applications
role of statewide planning
Transportation planning and policy guidance

3 C process

Planning tools

Travel demand modeling

Project level forecasts

Role of Statewide Planning
model research and development team
Technical service center for the branch

Provide expertise, research, and training in travel modeling

Advance travel modeling and analysis for the State of North Carolina

6 positions for advanced modeling

Model Research and Development Team
planning groups
MPO/RPO planning

17 MPOs

20 RPOs

Modeling for communities greater than 10,000 population

40 positions for planning/modeling

Planning Groups
transcad modeling status
3 regional models under development

Covering 9 MPOs

6 TransCAD MPO models currently in use

Developed ground up/converted

6 TransCAD MPO models in progress

Upgrades/new starts

10 non-MPO models

TransCAD Modeling Status
ncdot modeling improvement goals
NCDOT Modeling Improvement Goals
  • Develop “best modeling practices.”
  • Investigation of model improvements
  • New procedures to better address land use feedback
  • Tools to improve efficiency and reliability
why ncdot decided to switch platforms
Older platform no longer supported

Limited capabilities

Graphics, network size, TAZs

More GIS integration

Movement towards GIS based analysis

Compatible with ArcGIS

Ability to do spatial analysis

Why NCDOT Decided to Switch Platforms?
why transcad diverse users
Advanced developers


Advanced end users

Basic end users

Why TransCAD?Diverse Users
why transcad general
Windows based

Scenario manager for easy file management


Data and database


Why TransCAD?General
why transcad gis capabilities
Integration of GIS tools and technologies

Improved linkage between land use, transportation, and air quality

Development of database structures

Application batch files, GIS tools, and Graphical Users Interface

Why TransCAD?GIS Capabilities
why transcad modeling process

Interface with ArcGIS

GIS database

Existing data sources (census, others)


Why TransCAD?Modeling Process
why transcad modeling process16

GIS database with unlimited attribute capabilities

GIS distances and shapes

Database linkages to other data sets

Why TransCAD?Modeling Process
why transcad modeling process17
Trip generation

Robust cross classification model

GISDK programming for custom applications

Unlimited trip purposes

Multiple variables can be stored in TAZ land use data base or linked via parcel data base

Why TransCAD?Modeling Process
why transcad modeling process18
Trip distribution

Geocode survey data to determine trip lengths

Visualize desire lines between zones or districts

Utilize curve functions for friction factors in place of lookup table

Why TransCAD?Modeling Process
why transcad modeling process19
Mode choice

Built in procedures for streamlined transit analysis

Use GISDK to customize nested LOGIT model

Why TransCAD?Modeling Process
why transcad modeling process20
Traffic assignment

Easy time of day analysis

User defined link volume-delay equation

Multiple assignment algorithms

Comparison tools for evaluating different assignments

Why TransCAD?Modeling Process
why transcad modeling process21
Performance measures

Use database fields to easily query link types for evaluation

GISDK allows for consistent checking and reporting of model results

Visualization of results

Screenline analysis

User log available

Why TransCAD?Modeling Process
challenges tips conversion process
TIP: recommended for immediate use of TransCAD on existing models

TRIP: converted base is NOT ready to go

TIP: use performance measures to build confidence in converted model - will need to adjust for differences

TRIP: TransCAD recognizes real numbers - will account for differences

Challenges/tipsConversion Process
challenges tips
Think about things differently

File management

Dataview save

MAP save

Powerful computer



Users group


GISDK Tools for Travel Demand ModelingModel Research & Development UnitNCDOT Statewide Planning Branch

The Geographic Information System Developer’s Kit

(GISDK) provides you with a tool kit that you can use to get

outside the box and customize TransCAD in

any way you desire.

model team goal process improvement
Model Team Goal: Process Improvement

Through the development of applications tools for streamlining the model development process

meeting the process improvement goal
Meeting the Process Improvement Goal
  • Data management tool
  • Trip generation tool
  • Performance management tool
  • Miscellaneous tools
old way of managing model data
Old Way of Managing Model Data
  • Create separate fields for attribute data:
    • Travel time, capacity, ADT, facility type, functional classification, etc.
  • Enter data using TransCAD interface
  • Create multiple geographic files for different alternatives
disadvantages of the old way
Disadvantages of the Old Way
  • Manual recalculation of travel times and other attribute data
  • Current data entry approach is time consuming and prone to errors
  • Maintaining multiple geographic files is cumbersome and requires more disk space
  • Maintaining multiple geographic files increases the chance of introducing errors in the files
model data management tools36
Model Data Management Tools
  • TransCAD GISDK script
  • Select data values automatically calculated
    • Travel time, 1-way attributes, facility type, etc
  • Easy user interface for entering data
  • Provides a data management system for multiple model alternatives
  • Alternatives managed from master file
benefits of using data management tools
Benefits of Using Data Management Tools
  • Reduced errors
  • Increased efficiency
  • Eliminates duplicated data
  • Requires less disk space
  • Maintains the consistency of the model data
  • Standardizes model data management
calculate travel time tool
Calculate Travel Time Tool

Calculates travel time, 1-way capacity, 1-way ADT, facility code and functional classification code automatically every time data is changed

enter base data tool
Enter Base Data Tool

Provides a GUI (graphic user interface) to enter or modify base model data for single or multiple links

build base network tool
Build Base Network Tool

Builds the base network from the master line layer

identify new link tool
Identify New Link Tool

Identifies the future links that are not in the base network

enter alternative data tool
Enter Alternative Data Tool

Provides a GUI to enter or modify alternative network data for single or multiple links

build network alternative tool
Build Network Alternative Tool

Builds the network alternative from the master line layer

ncdot trip generation procedure
NCDOT Trip Generation Procedure
  • Average trip rate per household
  • Percentage applied to total trips to determine trips by trip purpose
  • Accounts for CV trips and non-home based trips by non-residents
  • Data input in ASCII format and executed in C+ program
disadvantages of the old way46
Disadvantages of the Old Way
  • Data input methodology is cumbersome and prone to data entry error
  • No ability to visualize data
  • User cannot easily interpret the data
benefits of using trip generation tool
Benefits of Using Trip Generation Tool
  • Reduced errors
  • Increased efficiency
  • Eliminates duplicated data
  • TransCAD data file facilitates visualization of data
model calibration and validation
Model Calibration and Validation
  • Iterative process
  • Based on observed data and reasonableness checking
  • GOAL: model performing within acceptable standards
  • Resources
    • Http://tmip.Fhwa.Dot.Gov/clearinghouse/docs/mvrcm
    • Http://ntl.Bts.Gov/docs/377cas.Html
benefits of using performance management tool
Benefits of Using Performance Management Tool
  • Standardization
  • Increased efficiency
  • Process is automated
  • Reduced user error
  • Great reporting tool