South Korea has experienced rapid economic development since the 1960s. However, pronounced regional disparities have concurrently emerged. Amid the escalating regional inequalities and persistent demographic challenges characterized by low fertility rates, regional decline has become a pressing issue. Therefore, the feasibility of expanding transportation networks as a countermeasure to regional decline has been proposed. This study utilizes the synthetic control method and spatial difference-in-differences methodologies to assess the impact of the 2017 opening of Seoul–Yangyang Expressway on economic development and population inflow within Hongcheon-gun, Inje-gun, and Yangyang-gun. The purpose of this study is to evaluate the effectiveness of highway development as a policy instrument to mitigate regional decline. Findings from the synthetic control method analysis suggest a positive impact of the opening of the expressway on Hongcheon-gun’s Gross Regional Domestic Product (GRDP) in 2018, as well as Yangyang-gun’s net migration rates from 2017 to 2019. Conversely, the spatial difference-in-differences analysis, designed to identify spillover effects, reveals negative impacts of the highway on the GRDP and net migration rates of adjacent regions. Consequently, although targeted transportation infrastructure development in key non Seoul Metropolitan cities may contribute to ameliorating regional imbalances, results indicate that such measures alone are unlikely to suffice in attracting population to small- and medium-sized cities outside the Seoul Metropolitan Area.

The objectives of the study are to assess the impact of green human resources management (GHRM) policies and knowledge on the environmental performance of a public transportation company employees. Data from 1130 respondents were analyzed using SmartPLS modeling. The findings that GRHM affected employees of a public transportation company mediated by roles of green human resources management policies and knowledge. GRHM affected public transportation employees’ environmental performance significantly. Employees in the public transportation industry can use the study’s results to their advantage by developing plans to increase their sense of belonging to the company and their impact on the environment. Therefore, many companies understand the value of public transportation employees as the forefront ‘agent of change’ towards a significant positive environmental change in the community.