1. 1 Toward Implementing Weather- Responsive Advanced Traffic Management and Information Systems Meead Saberi K. Robert L. Bertini Alex Bigazzi 2009 ITS World Congress, Sweden

2. 2 Objectives Prototyping the data fusion process using weather, traffic, and incident data sources for weather-responsive ATMIS Study the possible effects of weather on measured traffic flow

3. 3 Road Weather Management Database

4. 4 Study Area I-5 NB Freeway Portland, OR MP 302.5 MP 305.12 MP 307.9

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

6. 6 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

7. 7 Incident Data Data Source: Portland Oregon Regional Transportation Archive Listing (PORTAL) Data Characteristics: Recorded incidents including type of incident, the lanes that were blocked as a result of the incident, and the start and end time of the incident 2005, 2006 and 2007 (more than 2,700 incidents)

8. 8 Weather Categorization 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) Total N = 14,965 N(1) = 13,389 N(2) = 602 N(3) = 572 N(4) = 371 N(5) = 31 Note: ‘No rain’ data excluded from plot 0 100 200 300 400 500 600 123456789101112131415 Precipitation (0.01 inch/hour) Frequency (hours)

9. 9 25 35 45 55 65 01234567891011 Time of Day Median Speed (mph) No RainVery LightLightModerate 25 35 45 55 65 01234567891011 Median Speed (mph) 25 35 45 55 65 01234567891011 Median Speed (mph) 25 35 45 55 65 01234567891011 Median Speed (mph) 25 35 45 55 65 121314151617181920212223 Time of Day Median Speed (mph) 25 35 45 55 65 1213141517181920212223 Effects of Rainfall on Speed 25 35 45 55 65 1213141517181920212223 25 35 45 55 65 1213141517181920212223

10. 10 Statistical Significance Non-Parametric Kruskal-Wallis Test 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 01234567891011121314151617181920212223 Time of Day P-value

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

12. 12 Effects of Rainfall on Mean Flow Very Light Light Moderate 0 400 800 1200 1600 2000 0 400 800 1200 1600 2000 0 400 800 1200 1600 2000 0 500 1000 1500 2000 121314151617181920212223 Time of Day Median Flow (vph) 0 500 1000 1500 2000 0 500 1000 1500 2000 0 500 1000 1500 2000

13. 13 Statistical Significance Non-Parametric Kruskal-Wallis Test 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 01234567891011121314151617181920212223 Time of Day P-value

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

15. 15 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

16. 16 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

17. 17 Questions?Questions? Thank you!