Browsing by Author "Mathew, T.V."

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A multi-class first-order traffic flow model to explain the disordered behaviour of vehicles
(Taylor and Francis Ltd., 2022) Sreekumar, M.; Joshi, S.M.; Mathew, T.V.; Chatterjee, A.
Disordered traffic streams are generally characterised by the presence of numerous vehicle classes having different sizes and operational characteristics. Unlike homogeneous traffic flow, smaller vehicles percolate between the bigger ones, invalidating the lane discipline and therefore requiring a different modelling approach. Each vehicle traverses through a series of opportunities created by other vehicles that are not only viable but also accessible, thus defining a permeable medium. Our objective is to develop an analytical traffic flow model that quantifies such opportunities for individual vehicle classes to traverse downstream. Equilibrium speed functions have been redefined based on a new metric termed as traversable distance. The inter-class flow dynamics of small-sized vehicles has further resulted in a significant reduction in their travel time. © 2021 Hong Kong Society for Transportation Studies Limited.
Modeling multi-class disordered traffic flow subject to varying vehicle composition using the concept of traversable distance
(World Scientific, 2020) Sreekumar, M.; Mathew, T.V.
Disordered traffic stream at the microscopic level can be described as a permeable medium. Each vehicle is considered to traverse through a series of lateral gaps created by other vehicles. We develop a multi-class traffic flow model that considers such viable and accessible gaps for individual vehicle classes to traverse downstream. The model accounts for the varying shares of different vehicle classes. The concept of traversable distance and modified equilibrium speed functions are used to model the interplay among multiple vehicle classes. Using a higher order finite volume approximation method, evolution for a two-class traffic stream is shown. This model replicates prominent empirical characteristics exhibited by multi-class disordered traffic such as overtaking and creeping. Varying shares of smaller vehicles affect queue formation and discharge characteristics, and have significant impacts on roadway capacity. The model also could compute dynamic class-specific travel times at different vehicular compositions more realistically. © 2020 World Scientific Publishing Company.
Modelling multi-class disordered traffic streams using traversable distance: a concept analogous to fluid permeability
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2020) Sreekumar, M.; Mathew, T.V.
In multi-class disordered traffic conditions, the presence of numerous classes of vehicles having different size and operational characteristics invalidates the behaviour of lane discipline. Each vehicle traverses through a series of both viable as well as accessible gaps created by other vehicles, thus defining a permeable medium. In this paper, a plausible way to incorporate the disordered behaviour on macroscopic traffic stream modelling is discussed. A new metric termed as traversable distance has been formulated for characterising this behaviour, based on field observations. Based on class-specific traversable distances that correspond to a set of incommensurate density measures, equilibrium speed functions have been redefined. Disordered stream behaviour significantly affects the scatter in the equilibrium speed–density relationship which is a key input to macroscopic traffic flow models. Results from the modified speed functions based on traversable distance proved that the proposed methodology could considerably explain the scatter observed in the fundamental diagram. © 2020, © 2020 Hong Kong Society for Transportation Studies Limited.