  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 ramp metering and other lane
management strategies to mitigate the bottleneck effects of lane-changes.
