FREEWAY WEAVING SECTIONS: COMPARISON AND REFINEMENT OF DESIGN AND OPERATIONS ANALYSIS PROCEDURES

Weaving sections represent the common right-of-way that occurs when two or more crossing freeway traffic streams are traveling in the same general direction. In conjunction with the development of the 1985 Highway Capacity Manual (HCM), several procedures have evolved for the purpose of updating, revising, and replacing the 1965 HCM procedure for design and operations analysis of freeway weaving sections. The objectives of this paper are twofold: to present and review the latest three weaving procedures available to highway and traffic engineers, and to propose specific refinements to a simple weaving section procedure to account for the lane distribution of traffic upstream of the weaving section. These adjustments primarily involve the developmentof a lane-shift variable, which represents the average amount of peak-period passenger car lane shifts occurring under a given geometric configuration and prevailing traffic volumes. Statistical testing of the refined procedure aganist the three procedures at more than 50 sites nationwide indicated that the proposed procedure tends to predict observed average running weaving and nonweaving speeds more closely than do the other procedures in most cases.