This study applied a decision-based model with uncertainty to identify factors in mode choice and to rank their influence in attracting riders to available public transit modes in the city of Tehran. The model integrates a fuzzy Delphi method and a fuzzy analytic hierarchy process with fuzzy set theory to process opinion uncertainties. The surveys found that from highest to lowest in influence, the service attribute rankings were safety, reliability, frequency, comfort, travel cost, information provision, and accessibility. Based on these attributes, subway ranked highest in passenger attraction potential, followed by ride-hailing, bus rapid transit, vans and taxis, then public bus services. These findings support the hypothesis that it is worthwhile for big cities to ramp investments in public transit improvements even as ride hailing services proliferate with the potential to attract users away from more throughput-efficient and lower-cost services.

Background: Due to the growing demand for energy and environmental issues related to using fossil fuels, it is becoming tremendously important to find alternative energy sources. Bioethanol produced from switchgrass is considered as one of the best alternatives to fossil fuels. Methods: This study develops a two-stage supply chain modeling approach that first determines feasible locations for constructing switchgrass-based biorefineries in the state of North Dakota by using Geographic Information Systems (GIS) analysis. In the second stage, the profit of the corresponding switchgrass-based bioethanol supply chain is maximized by developing a mixed-integer linear program that aims to commercialize the bioethanol production while impacts of energy use and carbon emission costs on the supply chain decisions and siting of biorefineries are included. Results: The numerical results show that carbon emissions and energy consumption penalties affect optimal biorefinery selections and supply chain decisions. Conclusions: We conclude that there is no need to penalize both emissions and energy use simultaneously to achieve desirable environmental benefits, otherwise, the supply chain becomes non-profitable. Moreover, imposing emissions or energy consumption penalties makes the optimization model closer to supply sources while having higher land rental costs. Such policies would promote sustainable second-generation biomass production, thus decreasing reliance on fossil fuels.

No abstract