Abstract
It is common for travelers to experience increased travel times and speedreductions on freeways due to adverse weather conditions. Based on a platform of archived freeway (flow and speed), incident and weather data, thispaper aims to analyze and quantify the effect of weather on traffic flow parameters such as speed and flow using three year's data from the Portland, Oregon metropolitan region. Intelligent transportation systems applications in traffic management and traffic information can be greatly enhancedby developments of weather-responsive systems. The research summarized inthis paper is a first step towards implementing weather-responsive advanced traffic management and information systems.