Abstract
This article proposes a novel multi-criteria multi-commodity network flow (MCMCNF) model to help transport planners and other analysts holistically assess different types of transportation systems (TS). This model provides a tool to autonomously analyse the effect of expansions, tolls, different levels of congestion and accidents leading to potential insights into a network's resilience and vulnerability, emissions distribution and risk. Unlike the mono criterion network flow models used for some time, we propose the application of multiple objectives. In this article we investigate the application of two objectives. The first maximises the flow of commodities and the second minimises travel related costs. The travel cost is modelled generically and may include the distance travelled, travel time and access charges. The considered cost function is non-linear, so different linearization strategies are suggested. These permit the model to be solved efficiently using Separable Programming techniques and the ɛ-constraint method (ECM). We have applied the proposed model to a variety of case studies and demonstrate how different forms of sensitivity analysis can be performed. The numerical investigations have highlighted the specific features of the Pareto frontiers and the resilience and flexibility of the networks considered.
Highlights
Transportation systems are vital for moving passengers and freight, called commodities, between different locations, either positioned locally, nationally, or internationally
The number of search points used in the epsilon-constraint method (ECM) is N = 100, but more can be used if additional solutions are required
Our multi-criteria multicommodity flow model maximises the flow of commodities and vehicles and simultaneously minimises the incurred cost of travel for those commodities
Summary
Transportation systems are vital for moving passengers and freight, called commodities, between different locations, either positioned locally, nationally, or internationally. In this article the assessment of transportation system flow (a.k.a. capacity) is re-considered and an improved multi-criteria multi-commodity network flow model (MCMCNF) is proposed. There are many routes, which can be assigned to commuters and commodities To choose those routes, the travel time and travel cost of commuters and commodities should be incorporated; but to our knowledge this was not done in past network flow models. The travel time and travel cost of commuters and commodities should be incorporated; but to our knowledge this was not done in past network flow models Those costs are directly affected by route, congestion and the presence of access charges and other fees. Prior capacity models with single objectives provide solutions that are non-optimal with respect to a variety of other metrics, i.e. they provide dominated solutions.
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