Proposed Analytical Technique for Estimating Capacity and Level of Service of Major Freeway Weaving Sections

Weaving typically occurs where merging traffic movements cross over diverging movements. The prevalence of weaving areas on freeways warrants the need for analytical techniques that can reliably analyze or design these critical freeway components. However, previous research at the University of California suggested that existing analytical procedures may not predict weaving operation with a sufficient degree of reliability. Consequently, a more reliable procedure for evaluating weaving performance was developed. Unlike most existing procedures, the proposed technique evaluates traffic flow behavior in individual lanes of the weaving section. The procedure is applicable to major weaving areas, a subset of all weaving configurations. The proposed procedure predicts vehicle flow rates in critical regions within the weaving section as a function of prevailing traffic flow and geometric conditions. Predicted flows are then used to assess the capacity sufficiency and level of service of a subject weaving area. The model itself was developed using large amounts of empirical and simulation data, collected from a number of sites throughout California. Some of the more interesting traffic flow characteristics empirically observed on a single weaving site are highlighted. Moreover, the basic format of the proposed procedure is presented.