An extended FTOPSIS method for freeway route selection in the pre-feasibility study stage

In the pre-feasibility study stage of freeway construction, road engineers attempt to select an optimal scheme with the aim of guiding follow-up design and construction work. This requires the consideration of multiple fuzzy factors which formats a multi-criteria decision-making (MCDM) problem. The aim of this study is to develop a MCDM method reflecting the decision information significantly. Firstly, Fuzzy Technique for Order Preference by Similarity to an Ideal Solution (FTOPSIS) and improved FTOPSIS (I-FTOPSIS) for selecting freeway route scheme were analyzed, and then developed FTOPSIS (D-FTOPSIS) was proposed to better reflect the decision information. Then, the above three methods were adopted to sort route schemes of Lianhua section of Chaohui freeway, respectively. Finally, consistency and distinction of results obtained from the three methods were comparatively discussed. In addition, the significance of D-FTOPSIS method for reflecting decision information was proved through the case analysis. Results indicated that the relative closeness (RC)of each alternative scheme calculated by the three methods is different, but the ranking of alternative schemes are consistent, indicating that the proposed D-FTOPSIS method is reasonable. The more important conclusion is that the D-FTOPSIS method is more sensitive to weights of attributes. In summary, the D-FTOPSIS proposed by this study is effective and can be used for optimizing route scheme, particularly for cases when the decision information of experts need to be reflected as much as possible.