Weaving Analysis, Evaluation and Refinement

Weaving sections are common design elements on freeway facilities such as near ramps and freeway to-freeway connectors. When the traffic demands exceed the capacity at weaving areas congestion may occur, which affects the operation of the entire freeway section. Traffic operational problems also may exist at weaving areas even when traffic demands are less than capacity because of the complexity of vehicle interactions, resulting in poor level of service (LOS) and potential safety problems. Existing procedures for the design and analysis of freeway weaving sections have several shortcomings, and their practical application often produces inconsistent results.This report describes the work performed under PATH Task Order 6304. The objective of the study was to evaluate the existing weaving analysis procedures to determine under which conditions the “best available” tools are most effective. The HCM2000, Leisch and Level D methods were evaluated using field data from 36 weaving sections for a total of 189 data points of speeds and volumes. A weaving performance matrix was developed to assist in determining which method to be used for a given mix of design and operational characteristics in a weaving section.