A Model of Calculating for On-Ramp Junction Capacity of Freeway

The on-ramp control is one of the most effective approaches to resolve traffic jam problems in the traffic control system of freeway. With the analysis of the single ramp's running rules, it can provide the theory for the ramp traffic control, to consequently alleviate the progressively traffic problems. In the paper, the significance, the research situation and the research methods of on-ramp junction capacity are firstly introduced. By analyzing the characteristics of the on-ramp, this paper deduces a model for calculating on-ramp junction capacity based on the existed research production. The relationship between on-ramp merging rate, the Lane 1 flow entering the junction and the junction density is established in this model, and it has been calibrated by the field data collected on Hu-Ning freeway. Compared with the empirical formulas in Highway Capacity Manual 2000(USA), the results show that this model has overcome some defects of the empirical formulas, and the relationship between flow and density turns out to be consistent with the empirical formula.