Agenda Overview Why TransCAD Challenges/tips Initiatives Applications

Overview

Role of Statewide Planning Transportation planning and policy guidance 3 C process Planning tools Travel demand modeling Project level forecasts

Organizational Structure

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

Planning Groups MPO/RPO planning –17 MPOs –20 RPOs –Modeling for communities greater than 10,000 population 40 positions for planning/modeling

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

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 TransCAD?

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 TransCAD? Diverse Users Advanced developers Developers Advanced end users Basic end users

Why TransCAD? General Windows based Scenario manager for easy file management Visualization Data and database GISDK

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? Modeling Process Data –Interface with ArcGIS –GIS database –Existing data sources (census, others) –Visualization

Why TransCAD? Modeling Process Networks –GIS database with unlimited attribute capabilities –GIS distances and shapes –Database linkages to other data sets

Why TransCAD? Modeling Process 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 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 Mode choice –Built in procedures for streamlined transit analysis –Use GISDK to customize nested LOGIT model

Why TransCAD? Modeling Process 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 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

Challenges/tips

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/tips Think about things differently File management Dataview save MAP save Powerful computer

Initiatives

Initiatives Training Standards Users group Applications

Applications

GISDK Tools for Travel Demand Modeling Model Research & Development Unit NCDOT 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.

30 Model Team Goal: Process Improvement Through the development of applications tools for streamlining the model development process

31 Meeting the Process Improvement Goal Data management tool Trip generation tool Performance management tool Miscellaneous tools

Data Management

33 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

34 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

35 Model Data Management Tools

36 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

37 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

38 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

39 Enter Base Data Tool Provides a GUI (graphic user interface) to enter or modify base model data for single or multiple links

40 Build Base Network Tool Builds the base network from the master line layer

41 Identify New Link Tool Identifies the future links that are not in the base network

42 Enter Alternative Data Tool Provides a GUI to enter or modify alternative network data for single or multiple links

43 Build Network Alternative Tool Builds the network alternative from the master line layer

Trip Generation

45 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

46 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

47 Benefits of Using Trip Generation Tool Reduced errors Increased efficiency Eliminates duplicated data TransCAD data file facilitates visualization of data

Performance Management

58 Model Calibration and Validation Iterative process Based on observed data and reasonableness checking GOAL: model performing within acceptable standards Resources – –

59 Benefits of Using Performance Management Tool Standardization Increased efficiency Process is automated Reduced user error Great reporting tool

Miscellaneous Tools

For the things we have to learn before we can do them, we learn by doing them. -Aristotle