# Congestion Evaluation of Pedestrians in Metro Stations Based on Normal-Cloud Theory
## 4 Methodology
### Model Results and Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Facility** & **Index** & **LOS** & **GPC** \\ \hline \multirow{4}{*}{Channel} & \multirow{2}{*}{L1–L2} & \(P_{1}\) & B & \\  & & \(P_{2}\) & E & II \\  & & \(P_{3}\) & B & \\ \cline{2-4}  & & \(P_{1}\) & A & \\  & & \(P_{2}\) & A & I \\  & & \(P_{3}\) & A & \\ \hline \multirow{4}{*}{Stairway} & \multirow{2}{*}{Upward} & \(P_{1}\) & E & III \\  & & \(P_{3}\) & E & \\ \cline{2-4}  & & Downward & \(P_{1}\) & A & I \\ \cline{2-4}  & & \(P_{3}\) & A & \\ \hline \multirow{4}{*}{Platform} & \(P_{1}\) & D & \\  & & \(P_{4}\) & E & IV \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Assessment result between level of service (LOS) and GPC. Figure 8: Comparison of the candidate cloud with the template cloud for each facility. (**A1**) The template cloud (channel). (**B1**) The template cloud (stairway). (**C1**) The template cloud (platform). (**A2**) the candidate cloud (channel (L1-L2)). (**B2**) the candidate cloud (stairway (upward)). (**C2**) the candidate cloud (platform). (**A3**) the candidate cloud (channel (L2-L1)). (**B3**) the candidate cloud (stairway (downward)). As a result, the GPC in channel L1-L2 was grade II in the GPC assessment process, while the passenger crowd degree was in levels B, E, and B by the corresponding P1, P2, and P3 in the LOS assessment. The GPC in the platform was grade IV using the GPC assessment process, while the passenger crowd degree was in levels D and E in the LOS assessment. Therefore, GPC was better and more realistic in illustrating the grade of crowd in metro stations. For the channel facility in the L1-L2 direction, the GPC reached grade II in 13 time periods and remained in grade I in the rest of the time periods. For the channel facility in the L2-L1 direction, the GPC reached grade II in eight time periods. Besides that, the GPC reached grade III in four time periods, although the time length for each period was less than 30 s. The reason for the inconsistent crowding status in the two directions was that the time difference of the two directions in Line 1 caused staggered arrival of the passengers (i.e., passenger flow was not concentrated), while the arrival time of the two directions in Line 2 was much more consistent, which made the passenger flow concentrated and intense. Although the passenger flow intensity during the study time was not very high, the passenger flow growth followed an irreversible trend with the continuous construction of the Ningbo rail transit network. Given the continuous increase in the passenger flow, the GPC might reach grade IV. In that situation, the passenger flow intensity in the L2-L1 direction of the channel facility could be reduced by adjusting the arrival time of Line 2 in both directions, thereby reducing potential security risks. Overall, the current GPC for the facilities in the Gulou station was still considerable during the evening peak. Although the stairway facility did not show security risks due to no greater passenger flow in the study time, the safety hazards in the platform area were prominent and the safety hazards in the channel were more prominent as the passenger flow increased. Hence, some crowd safety management measures must be planned for accordingly beforehand.