## 2 Literature Review  
The impact HSRs have had have been studied from different perspectives worldwide. Because of the different environment in terms of connectivity, technology, and socioeconomic status, it is difficult to compare each case study and to draw a systematic and homogeneous conclusion [5]. Most studies on the impact of the HSR have focused on the regional economy and transport accessibility of the cities along the HSR line. [PERSON] et al. [7] reviewed the current situation and future challenges of the HSR in Europe in terms of inter-city relationships, wider spatial implications, and the role of HSR stations. [PERSON] et al. [8] developed a multilevel analysis (national, regional, and local levels) focusing on big intermediate cities along HSR lines: Cordoba and Zaragoza in Spain and Lille in France. [PERSON] et al. [9] developed a spatial computable general equilibrium model to evaluate the spatial distribution of user benefits. They applied the model to 22 infrastructure projects of the TEN-T priority list and found that 12 projects have a yearly rate of return of above 5% for the EU, while the remaining projects may be unprofitable. [PERSON] and [PERSON] [10] used panel survey data in China to investigate the direct and spillover impact on urban and rural regions. [PERSON] [11] studied the impact of HSR investment with respect to the economy and environment in China and found that the HSR stimulated the regional economy, and HSRs have had a significant positive impact on CO\({}_{2}\) emissions. [PERSON] and [PERSON] [12] studied the impact of the Shinkansen network extension on tourism development using survey data on tourism demand and tourist behavior. [PERSON] et al. [13] analyzed the different territorial performances of a national highway and an HSR line. They conducted a mobility survey and compared the modal split, travel frequencies, and travel purposes to understand long-distance mobility patterns. Although most previous studies found that the HSR had a positive effect on the regional economic growth, some researchers argued that there is a differential impact on the local economy, a negative effect on the local economic growth, and/or a mixed result [14; 15]. For example, [PERSON] et al. [14] estimated the future impact of the proposed European high-speed train network using the spatial distribution of the accessibility indicator based on a weighted average of the travel times, taking the gross domestic product (GDP) of the centers as the weights. They found that the proposed high-speed train network could increase the imbalances between the main cities and the nearby regions. [PERSON] et al. [15] analyzed the negative impact of the Gyeongbu KTX on regional economies, termed the \"straw effect.\" Straw effect refers to a negative economic impact, wherein local human resources and material goods are concentrated near metropolitan areas, whereas infrastructure construction negatively affects the local economy. They compared the impact of the KTX in 16 cities and argued that the introduction of the KTX negatively affected the regional economic growth. However, there is still no consensus regarding the existence of straw effects. For example, [PERSON] [16] investigated whether the KTX contributes to increasing population concentration in the Seoul metropolitan area, or whether the KTX leads to a depression in the market area in non-metropolitan areas. However, no concrete evidence was found regarding the straw effects of the introduction of the KTX. [PERSON] and [PERSON] [17] empirically analyzed the effect of the KTX on the regional economy and investigated the existence of straw effects. They found mixed results; an unbalanced regional economic growth was observed in terms of the gross regional domestic product (GRDP) and population distribution, such as the straw effect of the KTX, whereas balanced regional economic effects were observed in terms of employment. [PERSON] et al.