The development of weaving area analysis procedures for the next edition of the "Highway Capacity Manual," which is to be published in 2000, is described. Weaving has proved to be one of the most complex types of operation to analyze consistently. Although many studies and investigations have examined weaving areas, no single comprehensive research document exists that has resulted in an analysis procedure that has withstood the test of time and application, despite many attempts to do so. As the publication of the "Highway Capacity Manual" for the year 2000 (HCM 2000) nears, weaving analysis procedures continue to be influenced by a variety of historic studies and documents and by several databases. None of these is statistically adequate given the number of variables involved. Thus, procedures continue to require the application of the professional judgment of the members of the Committee on Highway Capacity and Quality of Service of the Transportation Research Board. Documentation for the analyses and judgments that support the analysis procedure as it is recommended to appear in the HCM 2000 is given in this paper.