## 2 Literature Review  
In preparation for the article, additional research was conducted into previous studies and projects that dealt with the application of MCDMs, both in the field of traffic analysis and in other multi-perspective decisions.  
The first subject of focus was on the advantages of cost-benefit analysis (CBA) in general, a precursor MCDM that focuses exclusively on monetary cost and benefits in decision making. Myriad studies within the European Union were analyzed, including [PERSON] et al. [5] in their paper \"Transport Infrastructure Evaluation Using Cost-Benefit Analysis\" and [PERSON] et al. [6] in their paper \"Why Cost-Benefit Analysis is perceived as a problematic tool for assessment of transport plans: A process perspective\". Both asserted that, although the model itself was useful as a tool, there were inherent flaws due to both the inability to define a clear parameter of value, as well as preconceptions and biases between decision-makers using the tool.  
These studies were not the only ones critical of the CBA methodology. [PERSON] et al. [7] were another such group, who set out to improve the scale of the CBA model to include other perspectives, such as sociological and environmental effects. They tested this new model on an airport expansion in the Netherlands in their paper \"A multicriteria decision report methodology for evaluating airport expansion plans\". Another researcher, [PERSON] [8], focused on questioning the assumptions made and their possibly erroneous conclusions in his paper, \"Cost-Benefit Analysis of Transportation Investments: Neither critical nor realistic\". Finally, a study held by two researchers, [PERSON] and [PERSON] [9], \"Twenty-one sources of error and bias in transport project appraisal\", set out to identify the main contribution to these errors, eventually citing the failure to balance the quantitative and qualitative data as the main contributor.  
With the CBA model seemingly ineffective, the research then focused on the next iteration, the life cycle assessment (LCA) and economic input-output (EIO) models, as well as their hybridized form, the EIO-LCA model. As the name implies, the LCA focuses on the societal impacts of a decision, dealing with the issues that arise during its lifetime of operation, while the EIO models focus on the economic and monetary costs of installation, only focusing on the future in terms of when a return on investment is expected. The EIO-LCA model, developed by [PERSON] et al. [10], was the next choice for the MCDM but was still incomplete.  
The next, and final model reviewed, was the Triple-Bottom Line (TBL) model, as outlined in the report \"Triple-Bottom-Line Accounting of Social, Economic and Environmental Indicators--A New Life-Cycle Software Tool for UK Businesses\" by [PERSON] and [PERSON] of the University of Sydney [11]). As an LCA model, it incorporated three of the main concerns in a decision: the economic, societal, and environmental results. Since this was serviceable for the purposes of this research, this model was used as a baseline for the development of the AHP model.  
Further research was performed as to the best way to develop the AHP model, and successful case studies were analyzed, such as the previously mentioned studies of [PERSON] et al. [3], [PERSON] et al. [12], [PERSON] et al. [13], and [PERSON] et al. [14]. These studies, as well as various more on dynamic traffic modeling and sustainability assessment, were all consulted in order to develop the AHP model used in this report.