## 4 Results and Discussion
### Clustering Results Analysis
#### 4.3.1 Comparative Analysis of Intercity Trip Chains from a Temporal Perspective
Figure 3: (**a**) Silhouette coefficient of intercity trip chain from Beijing to Tianjin (May 2019); (**b**) Silhouette coefficient of intercity trip chain from Tianjin to Beijing (May 2019); (**c**) Silhouette coefficient of intercity trip chain from Beijing to Shijiazhuang (May 2019); (**d**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Beijing (May 2019); (**e**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2019); (**f**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Tianjin (May 2019); (**g**) Silhouette coefficient of intercity trip chain from Beijing to Tianjin (May 2021); (**h**) Silhouette coefficient of intercity trip chain from Tianjin to Beijing (May 2021); (**i**) Silhouette coefficient of intercity trip chain from Beijing to Shijiazhuang (May 2021); (**j**) Silhouette coefficient of intercity trip chain from Beijing to Shijiazhuang (May 2021); (**k**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Beijing (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Tianjin (May 2021); (**g**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Beijing (May 2021); (**k**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Beijing (May 2021); (**k**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Tianjin (May 2021); (**k**) Silhouette coefficient of intercity trip chain from Tianjin to Shijiazhuang (May 2021); (**l**) Silhouette coefficient of intercity trip chain from Shijiazhuang to Beijing (May 2021); (**k**) Silhouette coefficient of intercity trip chain from  
Table 6 outlines the characteristics of the predominant trip chains from Beijing to Shijiazhuang in 2019 and 2021. For the Beijing to Shijiazhuang direction, compared to 2019, the type of arrival location shifted from visiting to residential in 2021. Under the impact of the epidemic, the demand for tourism travel had decreased, while the demand for stability in cross city living had increased. The age distribution of travelers changed from 30-34 years to 19-24 years, same with the direction from Shijiazhuang to Beijing. The trend of younger population mobility between Beijing and Shijiazhuang may have been related to the sharing of university resources and the employment market. In 2019, the group aged 30 to 35 may have mainly focused on tourism and business travel, and in 2021, the proportion of the younger residential group increased. The departure time shifted from 1 PM-2 PM to 8 AM-9 AM. Young people had the tendency to depart earlier, which is consistent with the Beijing-Tianjin direction. The waiting times at both the departure and arrival hubs decreased. This was because the transportation systems in Beijing and Shijiazhuang had become more efficient and convenient. Table 7 delineates the key attributes of the primary trip chain patterns observed between Tianjin and Shijiazhuang during the years 2019 and 2021. In the Tianjin to Shijiazhuang direction, the gender distribution of travelers changed from female to male in