Traffic Analysis Toolbox Volume XI: Weather and Traffic Analysis, Modeling and Simulation

December 2010

Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590
Web site: http://ops.fhwa.dot.gov

FHWA-JPO-11-019

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Table of Contents

[ Quality Assurance Statement ]	[ Technical Report Documentation Page ]
[ SI* (Modern Metric) Conversion Factors ]	[ Foreword ]

	Introduction and Purpose
Chapter 1	Why Weather?
Chapter 2	Weather Impacts on the Transportation System
	2.1 Macroscopic Level Impacts
	2.2 Microscopic Level Impacts
Chapter 3	Traffic Analysis Tools Incorporating Weather
	3.1. Overview
	3.2. Mesoscopic Analysis
	3.3. Microscopic Analysis
Chapter 4	Data Sources for Weather and Traffic Analysis
	4.1. Weather Data Sources
	4.2. Traffic Data Sources
	4.3. Intelligent Transportation Systems Data Sources
Chapter 5	Weather Responsive Traffic Operations and Management Strategies
	5.1. Advisory Strategies
	5.2. Control Strategies
	5.3. Treatment Strategies
Chapter 6	Case Study
	6.1. An Implementation of DYNASMART in Hampton Roads, VA. – Mesoscopic Simulation
	6.2. Traffic Signal Operation under Inclement Weather – Signal Optimization and Microscopic Traffic Simulation
	References

List of Tables

Table 2-1. Weather Impacts on Roadways and Traffic Operations

Table 2-2. Macroscopic Level Impacts on Traffic Operations

Table 2-3. Microscopic Level Impacts on Traffic Operations

Table 3-1. Calibrated Supply Parameters

Table 3-2. Weather Adjustment Factor Coefficients

Table 3-3. Demand Adjustment due to Inclement Weather Conditions

Table 3-4. Minimum Number of Simulation Repetitions

Table 6-1. Weather Sensitive Demand Parameters

Table 6-2. Weather Impacts on Traffic Demand

Table 6-3. RMSE between Observed and Simulated Speeds

Table 6-4. Parameters Adjusted During Calibration of Simulation Models

Table 6-5. Reduction Factors for Saturation Flow Rate and Free Flow Speed

Table 6-6. Performance Measures used for Benefit Assessment

Table 6-7. Benefits of Special Timing Plans – CORSIM Results for Dorset Street

Table 6-8. Benefits of Special Timing Plans – CORSIM Results for Vermont Route 15

List of Figures

Figure 3-1. Sample DynusT Network in Portland, OR (DynusT, 2010)

Figure 3-2. Flow Chart of Model Set Up

Figure 3-3. Calibration of Both Supply and Demand Data Process Flow Chart (Kunde, 2000)

Figure 3-4. Supply Parameter Calibration Procedure

Figure 3-5. Travel Time Comparisons under Three Weather Conditions

Figure 3-6. Weather Events during Peak Hour

Figure 3-7. Link Speed Comparisons

Figure 3-8. Calibration and Validation Process Flow Chart

Figure 3-9. Initial Evaluation Process

Figure 3-10. Example of X-Y plot with Acceptable Results

Figure 3-11. Concept of Acceptable Region

Figure 3-12. Relationship between Speed and Volume for Base and Weather Cases

Figure 4-1. Snapshot of Clarus Portal

Figure 4-2. National Climatic Data Center Website

Figure 4-3. UM Weather Homepage

Figure 4-4. Archived Data Management System (ADMS) Homepage

Figure 4-5. Performance Measurement System (PeMS) Homepage

Figure 4-6. PORTAL Homepage

Figure 4-7. Daily Statistics for I-5 North

Figure 4-8. Minnesota Department of Transportation Traffic Data Webpage

Figure 4-9. INRIX Homepage

Figure 5-1. WRTM Concept of Operations Flow Chart

Figure 6-1. Hampton Roads DYNASMART-P Network

Figure 6-2. Description of Weather Data in DYNASMART-P

Figure 6-3. Snapshots of WAF.dat files

Figure 6-4. DYNSMART-P Program

Figure 6-5. Hampton Roads DYNASMART-P Program Snapshot

Figure 6-6. Simulated and Observed Speeds

Figure 6-7. Dorset Street

Figure 6-8. Vermont Route 15

Figure 6-9. Impact of Inclement Weather Duration on Operational Benefits (Dorset Street)

Figure 6-10. Impact of Inclement Weather Duration on Operational Benefits (Route 15)