A Method of Weighting the Indexes of Greening Level for Infrastructures of Road Transportation

Since Chinese government proposes the strategies of peak carbon emissions and carbon neutral, the greening level of transportation system gets huge attentions. As a part of the road transportation system, the studies about greening level for infrastructures of road transportation is rare. To this end, this paper proposes a hybrid method of factor analysis and best-worst scaling to identify and weight the corresponding evaluation indexes. This method considers the correlation between evaluation indexes and evaluation object to avoid the subjective bias caused in the index selection. Specifically, 11 evaluation indexes are selected from the literature. A survey is conducted to collect opinions of experts that from industry, academic community and government toward these indexes. Next, factor analysis technique is adopted to explore the relationship between these indexes and green level of road transportation infrastructures based on the experts' rating information, which finds that the indexes of reliability and importance are less relevant, and other indexes can be constructed into a single factor called Index Relevance. Further, an improved best-worst scaling method is proposed combing the factor analysis technique to calculate index weights. The validity of the proposed method is verified by comparing to the traditional best-worst scaling method. Next, the improved method is adopted to calculate the weights of these evaluation indexes based on the factor Index Relevance and best-worst choice data. The evaluation indexes in top 3/4 of weights in sequence are (based on the results of 95% quantile of factor score): energy self-consistency (1.000), clean energy (0.702), refuse disposal (0.651), air pollution (0.589), intelligence (0.332), material use (0.324), virescence (0.303), and land use (0.277). The proposed method can contribute to the selection and weight calculation of greening-level indexes for infrastructures of road transportation and also contribute to the development of corresponding evaluation system.