Office of Operations
21st Century Operations Using 21st Century Technologies

Traffic Analysis Toolbox Volume XIV: Guidebook on the Utilization of Dynamic Traffic Assignment in Modeling

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U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590
www.ops.fhwa.dot.gov

Publication #: FHWA-HOP-13-015

United States Department of Transportation Federal Highway Administration

November 2012

Table of Contents

Executive Summary

1.0 Introduction

1.1 DTA Modeling Considerations

1.2 When to Use DTA?

1.3 Basic DTA Requirements

1.4 Purpose of This Guide

1.5 Organization of this Guide

2.0 DTA Fundamentals

2.1 DTA Primer Background

2.2 Equilibrium-Based DTA Approach

2.3 Non-Equilibrium DTA Approach

2.4 Multiple Traveler Classes (MTC)

3.0 Modeling Capabilities

3.1 Network Capabilities

3.2 Multi-Resolution Modeling

3.3 References

4.0 DTA Modeling Framework

4.1 DTA Modeling Process

4.2 Scoping

4.3 Data Collection

4.4 Base Model Building

4.5 Error and Model Validity Checking

4.6 Model Calibration

4.7 Alternatives Analysis

5.0 Data Requirements

5.1 Data For Network Development

5.2 Data For Model Calibration

5.3 Preparing a Data Collection Plan

6.0 Base Model Development

6.1 Development of Transportation Network

6.2 Development of Origin-Destination Information

7.0 Error and Model Validity Checking

7.1 Network Review

7.2 Review Demand

7.3 Model Validity Checking

7.4 Documentation

8.0 Model Calibration

8.1 Calibration Terminology

8.2 DTA Considerations

8.3 Calibration Process

8.4 Establish Calibration Objectives

8.5 Identify Performance Measures

8.6 Calibration Strategy

8.7 Model Validation

8.8 Model Calibration Checklist

9.0 Alternatives Analysis

9.1 Short-Term versus Long-Term Impacts

9.2 Random Variation

9.3 Warm Start versus Cold Start

9.4 Stand-Alone DTA Analysis versus Integrating with a Demand Model

9.5 Interpreting Model Outputs

DTA Applications

B. Foundations of Dynamic Traffic Assignment (DTA) Workshop: Selected Recent DTA Analyses

List of Figures

Figure 1.1 DTA Modeling Considerations

Figure 1.2 Model Scales

Figure 2.1 Traffic Variability

Figure 2.2 Static Traffic Assignment Algorithmic Structure

Figure 2.3 Dynamic Traffic Assignment Solution Algorithm Framework

Figure 2.4 General DTA Algorithmic Procedure

Figure 2.5 Static Assignment in a One-shot Simulation

Figure 2.6 Dynamic Assignment (with Feedback) in a One-shot Simulation

Figure 3.1 Demand-Supply Interactions for Evacuation Event

Figure 3.2 Multi-Resolution Modeling Frameworks

Figure 4.1 DTA Modeling Process

Figure 4.2 Sample Model Limits

Figure 4.3 Criteria for Selecting a Traffic Analysis Tool Figure

Figure 5.1 Variability in Spot Speeds at a Freeway Location

Figure 5.2 Route Choice Data

Figure 6.1 Example Modeling Process Flow Chart

Figure 6.2 Example Subarea Network

Figure 6.3 Example Corridor TAZ Disaggregation

Figure 6.4 Daily Profile of Trip Departures

Figure 7.1 Error and Model Validity Checking Process

Figure 7.2 Intersection Approach Geometry Attributes

Figure 7.3 Inconsistency between Connectivity and Traffic Control

Figure 7.4 Cumulative Curves Demonstrating Network Emptying

Figure 7.5 Convergence Example: Model not Approaching Convergence

Figure 7.6 Convergence Example: Model Approaching Convergence

Figure 8.1 DTA Model Calibration Framework

Figure 8.2 Calibration Objective Considerations

Figure 8.3 Comparison of Observed versus Model Estimated Speeds

Figure 8.4 Calibration Outliers

Figure 9.1 Baseline and Scenario Modeling Framework

Figure 9.2 DTA Feedback in a Trip-Based Travel Forecasting Framework

Figure 9.3 Feedback Project Modeling Framework

Figure 9.4 Link Volume Difference between Two Different Sets of Model Results

Figure 9.5 Speed/Density Plot for Links

Figure 9.6 Speed Contour Diagram for Corridor-Level Analysis

Figure 9.7 Network-Wide Animation of Traffic Dynamics

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