Abstract:
Disorderly traffic streams are those that, simply stated, do not
have parallel lines (or lanes) of vehicles but have vehicles distributed
more haphazardly in the road space. Vehicles in such streams, while
moving longitudinally, change their lateral positions frequently. Their trajectories
have a more pronounced wander along the width or the lateral
dimension as opposed to those vehicles that primarily move in lanes.
This property of disorderly streams dictates that its mathematical models
must admit two spatial dimensions (the longitudinal and the lateral).
Further, the observed impact of road geometry features like width, curvature,
etc., on stream behavior, irrespective of whether the stream is
disorderly, also suggests that realistic models of traffic streams must
describe the streams using two spatial dimensions. Unfortunately, most
of the theories of traffic dynamics are one-dimensional—they only consider
the longitudinal dimension. This paper, while describing many of
the existing approaches to modelling vehicular traffic behavior builds a
case for strengthening two-dimensional modelling approaches that are
all, still in their infancy. Given the (1) large increase in computation and
data handling capabilities over the last decade and (2) significant strides
made in developing tools for observing traffic dynamics at scales and
accuracy levels that were previously unimaginable, the authors believe
the time has come to develop, calibrate and validate reasonable twodimensional
models of traffic dynamics.