Regional Assessment of Weather Impacts on Freight
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Contact Information: Operations Feedback at OperationsFeedback@dot.gov
U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590
FHWA-HOP-16-044
February 2016
Table of Contents
Executive Summary
Chapter 1. Introduction
Background
Purpose of Study
Goals and Objectives
Overview of Candidate Datasets and Methodology
Chapter 2. Methodology
Selection and Definition of Study Areas
Final Data Processing Methodology
Final Databases
Chapter 3. Results
Atlanta Prototype
Cumulative Results
Chapter 4. Conclusion
List of Figures
Figure 1: Flowchart. Analysis Approach.
Figure 2. Map. Recommended Denver, Colorado study area and transportation focus.
Figure 3. Map. Atlanta, Georgia study area and transportation focus.
Figure 4. Map. Chicago, Illinois study area and transportation focus.
Figure 5. Map. Columbus, Ohio study area and transportation focus.
Figure 6. Map. Lake Tahoe, California study area and transportation focus.
Figure 7. Map. Lexington, Kentucky study area and transportation focus.
Figure 8. Map. Newark, New Jersey study area and transportation focus.
Figure 9. Map. Oklahoma City, Oklahoma study area and transportation focus.
Figure 10. Map. Pittsburgh, Pennsylvania study area and transportation focus.
Figure 11. Map. Raleigh, North Carolina study area and transportation focus.
Figure 12. Map. Rapid City, South Dakota study area and transportation focus.
Figure 13. Map. Salt Lake City, Utah study area and transportation focus.
Figure 14. Map. Seattle, Washington study area and transportation focus.
Figure 15. Map. Final Atlanta, Georgia transportation focus.
Figure 16. Map. Final Oklahoma City, Oklahoma transportation focus.
Figure 17. Map. Final Denver, Colorado transportation focus.
Figure 18. Chart. Time-of-day effects in the Atlanta, Georgia study area, averaged over all 23 Freight Analysis Framework segments.
Figure 19. Chart. Effects of different weather events over time in Atlanta, Georgia.
Figure 20. Chart. Change in speed from previous hour for all analyzed weather events in Atlanta, Georgia.
Figure 21. Chart. Number of weather events by type across all study areas.
Figure 22. Chart. Travel speeds during time periods with weather events relative to similar time periods under normal conditions.
Figure 23. Chart. Freight Analysis Framework segments across all study areas characterized by the nature of traffic flow.
Figure 24. Chart. Average loss in speed on even flow versus irregular flow roads for all weather events ("All") and for only weather events that decrease speeds ("Only Losses").
Figure 25. Chart. Trucks per day on even flow and irregular flow highways.
Figure 26. Chart. Average reduction in travel speeds due to weather on even flow versus irregular flow roads for each hour of the day.
Figure 27. Chart. Average speed by hour under normal weather conditions.
Figure 28. Chart. Average speed by hour for small, medium, and large study areas under normal weather conditions
Figure 29. Chart. Change in speed (miles per hour) due to weather events over time, averaged across all weather events and study areas.
Figure 30. Chart. Lagging Effect: Change in speed four hours after different types of weather events, across all study areas.
Figure 31. Chart. Winter weather accounts for over half of all lost time: Weather effects by weather event type, across all study areas.
Figure 32. Chart. The cumulative share of weather events and time lost when weather events are sorted by their impacts on traffic speed (percent decrease in speed).
Figure 33. Chart. Weather events associated with large impacts on traffic (greater than 10 percent decrease in speed) sorted by weather event type.
Figure 34. Chart. Weather events associated with the worst impacts on traffic (greater than 50 percent decrease in speed) sorted by weather event type.
Figure 35. Chart. The impacts of Wind weather events in each study area.
Figure 36. Chart. Average number of trucks per year passing through each of the 13 study areas during weather events. All 13 study areas together see 413 million truck passings per year total, with 9 million, or 2.2 percent of these passings occurring during weather events.
Figure 37. Chart. Raw Freight Analysis Framework volume data ("FAF") and adjusted Freight Analysis Framework volume data ("Adjusted") for each study area.
Figure 38. Chart. Raw Freight Analysis Framework volume data ("FAF") and adjusted Freight Analysis Framework volume data ("Adjusted") for individual Freight Analysis Framework segments within the Lake Tahoe, California study area
Figure 39. Chart. Distribution of adjusted Freight Analysis Framework volumes across the day using Transportation Economics' research, for even flow and irregular flow highways, across all study areas.
Figure 40. Chart. Distribution of adjusted Freight Analysis Framework volumes across the day using Transportation Economics’ research, for workdays and nonworkdays across all study areas.
Figure 41. Chart. Average length and travel time of Freight Analysis Framework segments across all study areas.
Figure 42. Chart. Percent increase in Freight Analysis Framework segment travel times for different weather event types, across all study areas.
Figure 43. Chart. Differences in travel time impacts between and within weather event types, across all study areas.
Figure 44. Chart. Costs of weather events by type in terms of cost per truck per segment and cost per segment hours.
List of Tables
Table 1. Freeway traffic flow reductions due to weather.
Table 2: Empirical studies on weather and traffic.
Table 3: Recommended study areas from the task 2 memo.
Table 4: Final list of study corridors.
Table 5: Weather event types included in National Oceanic and Atmospheric Administration s Storm Events Database.
Table 6: The 25 weather event types included in the final analysis.
