Browsing by Author "Ebrahimi, Sajad"

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A Fuzzy Delphi Analytic Hierarchy Model to Rank Factors Influencing Public Transit Mode Choice: A Case Study
(2020) Ebrahimi, Sajad; Bridgelall, Raj; Upper Great Plains Transportation Institute
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.
Three Essays on Renewable Jet Fuel Supply Chain Network Design and Traffic Safety
(North Dakota State University, 2022) Ebrahimi, Sajad
Because of rising energy consumption, climate change, and environmental concerns about fossil fuels, finding alternative renewable energy sources is becoming increasingly crucial. With the non-advanced share of the U.S. Renewable Fuel Standard having been mainly met by corn ethanol, many states are considering cellulosic or non-edible oilseed crops as the next source of biofuels. This study seeks to design a supply chain to produce renewable jet fuel (RJF) within the Midwest region and southeastern U.S. This is accomplished through the use of optimization models (mixed-integer linear programming). Furthermore, because RJF manufacturing incurs higher expenses than conventional jet fuel, the use of various monetary incentives is being studied to establish their usefulness in commercializing the supply chain. The findings of this study can be used by energy policymakers, RJF producers, and investors to operate in a competitive market while safeguarding the environment. In another study, we evaluate speeding crash risk in North Dakota counties. In the United States, one of the most common contributing factors to car crashes is speeding. Speeding impairs a driver's ability to control and steer properly, as well as respond to a dangerous situation in a timely manner. Speeding crashes account for one-third of fatal crashes in the United States and are one of the risks for drivers on U.S. highways. Speeding crash risk can vary among regions. When it comes to allocating road safety expenditures to regions in order to reduce speeding crashes, it's vital for road management to understand which areas are at higher risk and should be prioritized for safety measures. This study uses a failure mode effect analysis method to evaluate the speeding crash risk.