## 5 Conclusions  
With the fast development of the economy, many metropolitans have been built and connections between cities have become increasingly close in China. In response to this  
Figure 13: Travel destinations of different stay-time groups on weekdays. issue, many cities have extended their URT systems, which were initially built to serve passengers in urban areas only, to adjacent cities to meet the huge intercity travel demands in the past decade. Using the Xihuan Line of the Changsha metro, which connects Changsha and Xiangtan, as an example, this paper is designed to explore the travel patterns of intercity passengers by analyzing the real metro smart card data on typical weekdays and weekends. The main findings are shown as follows:  
1. The intercity ridership shows clear commuting patterns with AM and PM peaks on weekdays for both directions. However, on weekends, the ridership from Xiangtan to Changsha peaks at 9 AM to 11 AM, whereas the ridership from Changsha to Xiangtan peaks at 5 PM to 9 PM, which shows a clear tourism pattern. That is, many passengers living in Xiangtan went to Changsha for sightseeing, shopping, etc., as Changsha is one of hottest tourist destinations in China. In addition, the intercity ridership on weekends is much higher than that on weekdays. 2. The travel time shows no significant differences by direction or day of the week. Based on travel time, the GMM classified intercity ridership into two groups, i.e., the short-travel-time group with the average travel time being 32.9 min, and the long-travel-time group with the average travel time being 68.93 min, with the latter being the majority. For ridership from Xiangtan to Changsha, the short-travel-time group mainly alights around the Yanghu area, which is the closest well-developed community in Changsha to Xiangtan, whereas the long-travel-time group mainly alights around the city center of Changsha. 3. The stay time shows significant differences between weekends and weekdays. Based on stay time in Changsha, the GMM divided intercity ridership into two categories as well. Most passengers stay around 4.3 h, whereas the rest stay around 23.47 h. On weekends, the intercity passengers for tourism have different stay modes, but their destinations are similar. On weekdays, there are large differences in travel destinations between the short-stay-time group and the long-stay-time group, and their travel purposes are more diverse, including commuting (work, school, etc. ), leisure, and services (medical, etc.). Based on the findings, some measures might be taken to further promote the integrated development of the metropolitan area. Firstly, according to the characteristics of intercity ridership in the Changsha-Zhuzhou-Xiangtan metropolitan area, its methods and conclusions can provide reference for other urban agglomerations with the intercity metro. Secondly, considering the spatial distribution of the primary destinations for different travel-time groups, it is recommended to optimize urban transportation connectivity and enhance the integration efficiency between rail transit and other transport modes. For metro operations, measures such as shortening train intervals during off-peak hours in core areas (e.g., Wuyi Square and Furong Square) and installing additional wayfinding facilities at transfer hubs should be prioritized. Finally, considering the differentiated stay patterns of intercity ridership, it is suggested that relevant departments launch joint promotional packages linking scenic spots and hotels to extend intercity passengers' stay times and enhance urban attractiveness. These measures will further advance the integrated development of the Changsha-Zhuzhou-Xiangtan metropolitan area. In addition, at the theoretical level, our research comprehensively considers travel patterns from two dimensions of stay time and travel time and confirms that intercity passengers meet the Gaussian distribution, which can provide reference for related research.