Effect of weather on the relationship between flow and occupancy on freeways

The relationship between flow rates and roadway occupancies on freeways has been investigated in several recent papers. However, all the data in those investigations have come from ideal conditions. The purpose of this paper is to investigate the same relationship under adverse weather conditions. This paper begins by briefly describing the background for the incident detection logic, in order to explain the rationale for developing a solid quantitative treatment of the effect of bad weather. The second section describes the data that were used for the analysis, with particular reference to weather conditions. The third section, dealing with the analysis, includes both a discussion of the methods used and a presentation of the results. The fourth section presents the conclusions that have been drawn from the investigation.