## 2 Literature Review
### Environmental Impact  
[PERSON] et al. [19] examined the use of a cost-benefit analysis (CBA) in policymaking, with an emphasis on a case study of climate change adaptation in Bremen, Germany. A CBA is seen as useful in raising awareness of environmental assets and increasing the transparency of the policy-making process. The research identifies factors that facilitate or constrain the integration of a CBA into policy-making, such as the participatory process of conducting a CBA, knowledge building, and time and resource constraints. [PERSON] and [PERSON] [20] provide an overview of the relationship between climate change (CC) and transport companies (TC), with an emphasis on sustainable transport practices and TC adaptation strategies. The research identifies four macro themes: climate impacts on transport companies (ICTC), climate impacts of transport companies (ITCC), climate-related regulations and TC reporting, and sustainable strategies of transport companies. [PERSON] and [PERSON] [21] analyzed the environmental and economic aspects of passenger rail transport in Turkey using life cycle assessment (LCA) and life cycle costing (LCC) methods. The research focuses on high-speed rail (HSR) and conventional rail (CR) systems and their environmental and cost impacts. HSR has a higher environmental impact due to infrastructure (58%) and operations (42%), while for CR, they are 39% and 61%, respectively. The environmental factors examined include abiotic depletion, acidification, eutrophication, global warming, human toxicity, and freshwater ecotoxicity. Research conducted by [PERSON] et al. [22] deals with the development of an assessment framework using three techniques--simple additive weighting (SAW), interpretive structural modeling (ISM), and interpretive rating process (IRP)--to analyze transport and its impact on climate change. The authors introduce Ecological Modernization Theory (EMT) and describe a three-stage hybrid approach that uses SAW to reduce transport factors and measures to critical factors, ISM to examine the relationships between them, and IRP to rank them. [PERSON] et al. [23] investigated the impact of green transport on environmental sustainability in ten countries that have undergone an energy transition. The authors highlight the critical role of transport in greenhouse gas emissions and environmental degradation. They use a sophisticated econometric technique, quantiles through moments, to develop a green transport index and analyze the data. The research also examines the impacts of innovation, domestic investment, urbanization, and the quality of institutions on the ecological footprint. The results suggest that innovation, domestic investment, and institutional quality contribute to maintaining environmental quality, while urbanization increases the ecological footprint. The simulation results of [PERSON] [24] using a cost-benefit analysis suggest that plug-in hybrid and electric city buses have the best potential to reduce energy consumption and emissions. However, when selecting hybrid and electric city buses for fleet operation, it is essential to consider the operating schedule and route planning. When applying both environmental and climate change impacts in CBAs, different approaches and the structure of pollutant emissions, including greenhouse gas emissions, are applied. Most global emissions come from the combustion of fossil fuels, which releases carbon dioxide (CO\({}_{2}\)) into the atmosphere. In addition to CO\({}_{2}\), emissions also come from other greenhouse gases, namely, methane (CH\({}_{4}\)) and nitrous oxide (N\({}_{2}\)O). Although CH\({}_{4}\) and N\({}_{2}\)O emissions are smaller in the atmosphere, they have a more substantial impact on the climate. Individual gases have been assigned weighted values based on their potency as greenhouse gases to simplify the accounting of greenhouse gases. This potency is referred to as the global warming potential (GWP), and their standard unit is the carbon dioxide equivalent or CO\({}_{2}\)[25].