Abstract:In this paper, we study various distribution schemes for determining flows through a merge in the supply-demand framework. Upon a thorough analysis of existing schemes, we propose a simple distribution scheme that satisfies the "fairness" condition, in which the flow from an upstream link is proportional to its traffic demand. We demonstrate that this scheme can capture characteristics of a merge, such as characteristic difference between upstream links, capacity of each link, and control of an on-ramp. Moreover, this scheme leads to a merge model that is computationally efficient and easy to calibrate. Wave solutions of a general Riemann problem will be of interest in future studies.Keywords: The kinematic wave traffic flow models, the discrete merge model, traffic demand, traffic supply, the supply-demand method, the distribution scheme, the "fairness" condition.

Frequent lane-changes in highway merging, diverging, and weaving areas could disrupt traffic flow and, even worse, lead to accidents. In this paper, we propose a simple model for studying bottleneck effects of lane-changing traffic and aggregate traffic dynamics of a roadway with lane-changing areas. Based on the observation that, when changing its lane, a vehicle affects traffic on both its current and target lanes, we propose to capture such lateral interactions by introducing a new lane-changing intensity variable. With a modified fundamental diagram, we are able to study the impacts of lane-changing traffic on overall traffic flow. In addition, the corresponding traffic dynamics can be described with a simple kinematic wave model. For a location-dependent lane-changing intensity variable, we discuss kinematic wave solutions of the Riemann problem of the new model and introduce a supply-demand method for its numerical solutions. With both theoretical and empirical analysis, we demonstrate that lane-changes could have significant bottleneck effects on overall traffic flow.In the future, we will be interested in studying lane-changing intensities for different road geometries, locations, on-ramp/off-ramp flows, as well as traffic conditions. The new modeling framework could be helpful for developing

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