Jin-Seok Hahn

Heterogeneous preferences of green vehicles by vehicle size: Analysis of Seoul case

ABSTRACT Although there are several policies for promoting green vehicles, green vehicles have yet to penetrate the market to the extent desired. To attain the goal, a complete understanding of consumers’ preferences of green vehicles is essential. This paper proposes and specifies the fuel-type choice models among conventional gasoline vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and electric vehicles by vehicle size using the stated preferences data collected in Seoul, Korea. The results highlight the need to accommodate the correlation between similar alternatives and the unobserved heterogeneity within the context of choosing a green vehicle. The choice probabilities of green vehicles are affected by the relative impacts of the vehicles’ attributes and socio-demographic variables, and both of these variables are affected by the sizes of the vehicles. For compact size and mid-size vehicles, the effects of operating costs were less than those of purchase prices; however, for the subcompact vehicles, the effects of operating cost were greater than those of purchase price. The parameter of operating costs was not statistically significant in the full-size model. With respect to electric vehicles, the availability of fuel stations would be more important in Seoul than in the U.S. These results can also be useful for policy makers in that they provide information about the impact of green vehicles’ attributes on the choice probabilities of green vehicles.

Sustainability evaluation of rapid routes for buses with a network DEA model

ABSTRACT This study establishes a network data envelopment analysis (DEA) model to evaluate the sustainability of public transportation services targeting rapid routes for buses in the Seoul metropolitan area. A network DEA-based optimization model is formulated to evaluate the sustainability of the public transportation service. By considering public transportation services from both the operators’ and users’ perspectives, this model produces results that reflect the interaction of three sustainable transport service properties, i.e., efficiency, equity, and environmental impacts. It is identified that the expansion of median bus lanes and the conversion of conventional buses into compressed natural gas vehicles could improve the sustainability of the public transportation services in the Seoul metropolitan area. Some limitations and future research agenda also are presented.