1 / 24

The Effects of Weather on Freeway Traffic Flow

The Effects of Weather on Freeway Traffic Flow. Alex Bigazzi. 2009 ITE Quad Conference , Vancouver, B.C. Meead Saberi K. Priya Chavan Robert L. Bertini Kristin Tufte. Visibility. Precipitation. Wind Speed. Speed. Flow. Objectives. Study Area. I-5 NB Freeway Portland, OR. MP 302.5

roland
Télécharger la présentation

The Effects of Weather on Freeway Traffic Flow

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Effects of Weather on Freeway Traffic Flow Alex Bigazzi 2009 ITE Quad Conference , Vancouver, B.C. Meead Saberi K. Priya Chavan Robert L. Bertini Kristin Tufte

  2. Visibility Precipitation Wind Speed Speed Flow Objectives

  3. Study Area I-5 NB Freeway Portland, OR MP 302.5 MP 305.12 MP 307.9

  4. Traffic Data Data Source: Portland Oregon Regional Transportation Archive Listing (PORTAL) Data Characteristics: Weekdays 2005, 2006 and 2007 (14,965 hours) Hourly aggregated dual-loop detector data Incident free hours

  5. Weather Data Data Source: National Oceanic and Atmospheric Administration (NOAA) Weather Station: Portland International Airport (PDX) Hourly rainfall, visibility and wind speed

  6. Weather Categorization Total N = 14,965 N(1) = 13,389 N(2) = 602 N(3) = 572 N(4) = 371 N(5) = 31 Rainfall Classification: 1) No rain 2) Very light rain (0-0.01 in/hr) 3) Light rain (0.02-0.04 in/hr) 4) Moderate rain (0.05-0.16 in/hr) 5) Heavy rain (>0.16 in/hr) Note: ‘No rain’ data excluded from plot

  7. Weather Categorization Total N = 14,965 N(1) = 14,084 N(2) = 881 Visibility Classification: 1) High visibility (>5 mi) 2) Low visibility (≤5 mi) Note: measurement maximum of 10 mi (excluded from plot)

  8. Weather Categorization Total N = 14,965 N(1) = 531 N(2) = 14,434 Wind Speed Classification: 1) High wind speed (>15 mph) 2) Low wind speed (≤15 mph)

  9. Effects of Rainfall on Speed

  10. Statistical Significance Non-Parametric Kruskal-Wallis Test

  11. Effects of Rainfall on Mean Speed Probabilistic Approach 17:00

  12. Effects of Rainfall on Mean Flow

  13. Statistical Significance Non-Parametric Kruskal-Wallis Test

  14. Effects of Rainfall on Mean Flow Probabilistic Approach 17:00

  15. Effects of Visibility on Speed

  16. Statistical Significance Non-Parametric Mann-Whitney Test

  17. Effects of Visibility on Mean Flow

  18. Statistical Significance Non-Parametric Mann-Whitney Test

  19. Effects of Wind Speed • Wind speed effects on speed and flow were similar to visibility effects • High winds corresponded with low visibility

  20. Conclusions • We observed traffic changes with rain at these locations; amount varied with intensity and hour of day • Speeds up to 7 mph lower when raining • Flows up to 230 vph lower when raining • Effects not always statistically significant – relationship with congestion is unclear • Unknown seasonal influences • Unknown sensitivity to weather categorization

  21. Conclusions • We observed traffic changes with visibility at these locations; amount varied with hour of day • Speeds up to 5 mph lower with low visibility • Flows up to 150 vph lower with low visibility • Effects not always statistically significant • Unknown categorization sensitivity • Unknown seasonal influences • Possible correlation with rainfall effects

  22. Conclusions • We observed traffic changes with wind speed at these locations; amount varied with intensity and hour of day • Speeds up to 6 mph lower with high winds • Flows up to 170 vph lower with high winds • Effects not always statistically significant • Unknown categorization sensitivity • Unknown seasonal influences • Possible correlation with rainfall effects

  23. Next Steps • Work with higher resolution weather and traffic data (5-min aggregated weather data are also available) • Look at more sites • Sensitivity analysis of weather classification

  24. Questions? Thank you!

More Related