Student Researcher: Meead Saberi K.

Faculty Advisor: Robert L. Bertini

ABSTRACT: This study describes an analysis of hourly weather and traffic conditions (speed and flow) at several locations on northbound Interstate 5 in Portland, Oregon using data collected over three years and based on a platform of archived freeway speed, flow, incident and weather data. The study aims to quantify a possible measurable effect of weather conditions on traffic speed and flow. First, the connection between weather conditions and incidents is studied. It is shown that the presence of incidents slightly influences the analysis of the effects due to rain on measured traffic flow. After removing periods affected by incidents, traffic data are examined under different weather conditions. During uncongested hourly periods, at the locations analyzed, a significant difference was noted between speed and flow under different rainfall conditions. During congested periods, the flow and speed differences observed were not significant. Further analysis is described during congested periods. Finally, a macroscopic analysis is used to display possible effects of rainfall on the traffic flow fundamental diagram. In the context of intelligent transportation systems, analyses such as these may lead to improved weather-responsive applications in traffic management and information.

PRODUCTS:

conferenceproceedings Saberi, M. and R.L. Bertini, " Empirical Analysis of the Effects of Rain on Measured Freeway Traffic Parameters." 89th Annual Meeting of the Transportation Research Board, Washington, D.C., 2010.

poster Saberi, M. and Bertini, R.L., "Does Weather Affect Traffic Flow on Freeways?." Transportation Research Forum, 50th Annual Forum, Portland, Oregon, March 16-18, 2009.

poster Saberi, M., Chavan, P., Bertini, R.L., Tufte, K., "Does Weather Affect Traffic Flow on Freeways?." The 6th Annual Region X Student Conference, University of Washington, Seattle, November 2008.