Research on Efficient Operation for Compound Interchange in China from an Auxiliary Lanes Configuration Aspect

Interchanges are the key nodes of the freeway. Due to the existence of weaving behavior, the traffic flow situation is more complicated for small spacing interchanges. Continuous auxiliary lanes are usually used to connect the entrance and exit to form a compound interchange to reduce the interference of weaving behavior. However, when it comes to the design of auxiliary lane forms, China lacks relevant design specifications and research in this area. As a result, there often exists the phenomenon of mismatch between the design form and the traffic volume. In this paper, we took a compound interchange in Xi’an as the research object, proposing four auxiliary lane design schemes and using VISSIM (2022 student) software to establish the simulation model. Additionally, various traffic conditions were simulated through sensitivity analysis. Finally, using the factor analysis method and entropy method, we comprehensively assigned weights to the indexes. By obtaining the weighted scores for various schemes, it became possible to determine the applicability of each scheme under different traffic conditions. The results indicate that the gradient auxiliary lane can be applied to most traffic conditions and has a smaller land occupation than the traditional design, which is an optimization and improvement for the traditional design form.