Enhanced validity and reliability of spatial decision support systems (SDSS) for sustainable transportation decision-making

• The reliability and validity of spatial decision support systems (SDSS) are enhanced.
• Variable grouping and weighting process is conducted using confirmatory factor analysis to provide a robust factor structure.
• Route alternatives are examined with both the grand total suitability scores and the detailed value estimation for each factor.

The use of spatial decision support system (SDSS) is widely defined by various scholars and research projects. One good example would be in the area of transportation planning. With the recent emphasis on the relationship between transportation and environmental impact, adoptable nature of geographic information systems (GIS) with its spatial data management received particular attention. This perspective especially serves the area of the preliminary plan for a new transportation corridor as the utilization of GIS enables researchers to pinpoint the changes in natural landscape as well as physical environment. There are, however, constraints in the coordinated use of SDSS and transportation planning. Especially, the validity and reliability side of SDSS have been constantly challenged by many scholars. Although SDSS provides an advantage to create multiple alternatives, its subjective weighting process sometimes questions effectiveness of the final outcome. Therefore, this study aims to relieve the two limitations by incorporating confirmatory factor analysis and raster-based suitability matrix under the domain of transportation planning. As a result, the following research questions were answered: 1) Using confirmatory factor analysis, do input variables group based on their underlying implications?; and 2) Does the suitability matrix reflects each route's suitability score based on its emphasis? The modeling process adequately meets the need for logical weighting and systematic grouping process, and the final outcome is also examined by a suitability matrix clearly indicating that the proposed SDSS supports for more evidence-based planning practice.