Model Validation and Reasonableness Checking Manual
Prepared by
Barton-Aschman Associates, Inc.
Cambridge
Systematics, Inc.
Prepared for
Travel Model Improvement Program
Federal Highway
Administration
February 1997
Table of Contents
- 1.1 Purpose of Manual
- 1.2 Target Audience
- 1.3 Overview of the Model Validation Process
- 1.4 Validation Issues
- 1.4.1 Types of Validation Checks
- 1.4.2 Level of Aggregation
- 1.4.3 Validation Data Sources
- 1.4.4 Sources of Error
- 1.4.5 Accuracy Requirements
- 1.5 Organization of Manual
- 2.1 Land Use and Socioeconomic Data
- 2.2 Transportation Network Definition
- 2.3 Forecasting and Monitoring Inputs
- 3.1 Socioeconomic Disaggregation Submodels
- 3.2 Trip Productions
- 3.3 Trip Attractions
- 3.4 Special Generators
- 3.5 Modeling Trips for Other Purposes
- 3.6 Balancing Productions and Attractions
5.0 Mode Choice / Auto Occupancy
6.0 Time-Of-Day/Directional Split Factors
- Appendix A - 1990 Journey to Work Summary by State
- Appendix B - Observed and Estimated Average Trip Lengths in San Juan
- Appendix C - Trip Distribution Validation Summary (New Orleans)
List of Figures
1-1 Role of Model Validation
1-2
Validation Process
1-3 Effect of
Compounding Error in Model Validation
2-1 GIS Plot of Socioeconomic Data
2-2
Network Coding Convention
2-3 Coding of
Centroid Connectors
2-4 Network
Path-Building Trees
2-5 Color-Coding of
Network Attributes
2-6 Example of
Screenline Locations
2-7 Example of
Cutline Locations
3-1 Household Size Disaggregation Model
3-2
Observed vs. Estimated Households by Census Tract
3-3
Trips per Capita - Selected U.S. Cities
4-1 Home-Based Work - Trip Length Frequency
Distribution
4-2 Coincidence Ratio for
Trip Distribution
4-3 Normalized
Friction Factors
6-1 Diurnal Distribution of Trips (NPTS)
7-1 Travel Times and Speeds Using BPR Function
7-2
Maximum Desirable Deviation in Total Screenline Volumes
7-3
Assigned versus Observed Average Daily Traffic Volumes
7-4
Maximum Desirable Error for Link Volumes
List of Tables
1-1 Estimated Accuracy of Some Parameters in the Travel Modeling Process
2-1 Summary of Demographic Trends from the NPTS
3-1 Households by Autos Owned and Income
3-2
Observed and Estimated Households by Size Subgroups
3-3
Trip Estimation Variables from NCHRP 365
3-4
Average Motorized Person Trips per HH by Region
3-5
Comparison of Person Trips per Household
3-6
Comparison of Percentage of Person Trips by Purpose
3-7
Aggregate Trip Generation Checks, Albuquerque
4-1 Example Look-Up Speed Table
4-2 Terminal Times
4-3 Comparison of Trip Lengths Among Cities
4-4 Commuting Patterns of Home-to-Work Trip by Mode
5-1 Review of Mode Choice Coefficients For Home
Based Work Trips
5-2 Review of Mode
Choice Coefficients For HBNon-Work and NHB Trips
5-3
HBW Classification by Automobiles per Household
5-4
HBW Classification by Household Income
5-5
Average Vehicle Occupancy for Selected Trip Purposes
7-1 Look-up Table of Free-Flow Speeds and Link
Capacities
7-2 Updated BPR Parameters
Using HCM Procedures
7-3 Example VMT
Validation Summary
7-4 Urban Area VMT by
Facility Type
7-5 Percent Root Mean
Square Error Comparisons
7-6 Percent
Root Mean Square Error - 24-Hour Assignment (Reno)
7-7
Percent Difference Targets for Daily Traffic Volumes by Facility Type
7-8
Percent Difference Targets for Daily Volumes for Individual Links
