This paper aims to determine the degree to which the capacity of the junction between the off-ramp and the ground road of the urban elevated expressway is affected by the vehicle weaving ratio. Based on the investigation of a typical road section in Xi'an, two kinds of capacity simulation experiments are designed. The length of interlaced area and the proportion of right turn of ground road traffic flow are taken as variables. In this paper, a capacity reduction coefficient model based on the capacity of adjacent downstream intersections is proposed. The results show that when the right turn ratio of ground road traffic flow is less than 0.2, the capacity reduction coefficient is 0.8≤γ≤1, and the capacity of the connecting part mainly depends on the length of the interleaving zone which meets the requirement of safe lane changing distance. Finally, the validity of the model is verified by two example road sections in Xi'an and Jinan.

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