## 5 Contributions and Limitations  
This paper presented an HRS assessment methodology for selecting a preferred alignment while reducing a calculated threat score for mountainous highways. The study developed a systematic, data-driven framework for analyzing road alignment alternatives by assessing multiple risk factors related to geometric design and environmental factors. This approach aids in designing roads with safety and environmental considerations and al  
Figure 17: Threat Raster Maps of Preferred Alignment. (**a**) Curve Radius. (**b**) Deflection Angle. (**c**) Horizontal Curve Length. (**d**) Vertical Alignment Change. (**e**) Longitudinal Grade. (**f**) Slope Length. (**g**) Flood Hazard. (**h**) Lithology Type. (**i**) Lineament. (**j**) Threat Score. lows for a more quantitative assessment of safety, moving beyond the traditional qualitative \"safe or unsafe\" design approach. When compared to previous studies such as [PERSON] et al. [6], which integrated FTA and DEMATEL to measure geometric design quality, our study incorporated a multidimensional approach that simultaneously considers geometric, hydrological, and geological factors. Therefore, the resulting design risk factors and weights were different. In addition, GIS was used to visualize and analyze the threat scores of different road alternatives and to quantifiably compare between these alternatives. Additionally, previous studies mentioned in Sections 1.2 and 1.3 separately address hydrology and geology aspects. Our study integrates these factors to select the most suitable or preferred alignment. From a hydrological perspective, the hazard maps generated through floodplain mapping go beyond traditional highway studies that focus solely on providing flood mitigation measures for a predetermined alignment. The approach allows for the proactive identification of flood risks and the development of alignments that minimize exposure to these hazards. The methodology used HEC-RAS 2D to simulate flood dynamics and design roads with improved flood resilience. This data-driven approach ensures that critical infrastructure can withstand hydrological challenges in mountainous regions, leading to safer and more reliable transportation networks. The methodology incorporated rainfall analysis, topographic study, floodplain 2D hydraulic simulation, hazard map creation, and road infrastructure considerations. From a geological perspective, this research highlighted the importance of integrating detailed geological mapping into the highway design optimization process. By characterizing rock types and properties, the methodology allows engineers to select alignments with greater stability and minimize risks associated with geological hazards, potentially lowering construction costs by avoiding unstable areas and optimizing excavation requirements. The study identified 14 design factors, as presented in Table 1, impacting road safety through an FTA approach, with risk intensity values determined from previous literature and guidelines. The study incorporated horizontal curve length, deflection angle, vertical curve length, and longitudinal grades. Having these factors within appropriate ranges, as explained, will provide improved stability for the vehicle. The DEMATEL method was then used to weigh design factors. Results of the process showed that the design factor with the highest importance is the curve radius (\(q_{i}=2\)), followed by horizontal alignment change (angle of deflection) and vertical alignment change (\(q_{i}=1.83\)), horizontal curve length (\(q_{i}=1.33\)), and longitudinal grades (\(q_{i}=1.167\)). The four hydrological and geological factors (\(H\), \(I\), \(Li\)t, and \(LiD\)) were of equal and moderate importance (\(q_{i}=0.66\)). The practical application of this methodology to Quesir Road in the Golden Triangle Region demonstrated its effectiveness and relevance in a real-world scenario. Multiple alignment alternatives were generated based on geometric, hydrological, and geological considerations.