Empirical Analysis of the Effects of Rain on Measured Freeway Traffic Parameters

This paper 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, analysis such as these may lead to improved weather-responsive applications in traffic management and information.


  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 15p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01154621
  • Record Type: Publication
  • Report/Paper Numbers: 10-2331
  • Files: BTRIS, TRIS, TRB
  • Created Date: Jan 25 2010 11:04AM