## 4 Results
### Terrain Spatial Perception  
In order to ensure the effectiveness of the subsequent modeling research, IBM SPSS 26 software should be used to test the scale data in the questionnaire. As shown in Table 3, the questionnaire data successfully passed the Cronbach and Kaiser-Meyer-Olkin (KMO) tests [45], indicating that the data met the requirements of multivariate normality and sampling adequacy, thus ensuring reliable data quality [40]. In addition, the cumulative variance explanation rate is greater than 40% [45]. As shown in Table 4, composite reliability (CR) and average variance extracted (AVE) were used to assess the reliability and validity. The CR and AVE values for all dimensions are above 0.7 and 0.4, respectively. This suggests that the measurement indicators of latent variables presented in Table 1 exhibit strong reliability and validity [46]. The result of the two-order confirmatory factor analysis is shown in Figure 4. AMOS 28.0 was used to estimate the parameters of SEM. Chi-square degrees of freedom (CMIN/DF), approximate root mean square error (RMSEA), root mean square residual (RMR), goodness \begin{table}
\begin{tabular}{l l c c c} \hline \hline
**Latent Variable** & \multicolumn{2}{c}{**Factor Load Coefficient**} & **AVE** & **CR** \\ \hline \multirow{3}{*}{Security perception} & SEC1 & 0.804 & \multirow{3}{*}{0.627} & \multirow{3}{*}{0.834} \\  & SEC2 & 0.821 & & \\  & SEC3 & 0.749 & & \\ \hline \multirow{3}{*}{Convenience perception} & CON1 & 0.823 & \multirow{3}{*}{0.620} & \multirow{3}{*}{0.867} \\  & CON2 & 0.803 & & \\ \cline{1-1}  & CON3 & 0.752 & & \\ \cline{1-1}  & CON4 & 0.769 & & \\ \hline \multirow{3}{*}{Comfort perception} & COM1 & 0.679 & \multirow{3}{*}{0.617} & \multirow{3}{*}{0.826} \\  & COM2 & 0.924 & & \\ \cline{1-1}  & COM3 & 0.732 & & \\ \hline \multirow{3}{*}{Accessibility perception} & ACC1 & 0.762 & \multirow{3}{*}{0.608} & \multirow{3}{*}{0.861} \\ \cline{1-1}  & ACC2 & 0.877 & & \\ \cline{1-1}  & ACC3 & 0.751 & & \\ \cline{1-1}  & ACC4 & 0.720 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Reliability and validity tests. Figure 3: Descriptive statistical characteristics of respondents. of fit index (GFI), comparative fit index (CFI), normalized fit index (NFI), Tucker-Lewis index (TLI), incremental fit index (IFI), and standardized root mean square residual (SRMR) were used to assess the fitness of model. The model has a high degree of fitness and meets the standard requirements [40], as depicted in Table 5.  
According to Table 5, the four-part perception outlined in this paper--security perception, convenience perception, comfort perception, and accessibility perception--can effectively elucidate travelers' terrain spatial perception. Furthermore, we can draw an interesting conclusion from Table 6 that the significance of accessibility, convenience, security, and comfort in P&R travel diminishes successively in travelers' perception of terrain space in river-valley-type cities. This conclusion points to the priority of the river-valley-type cities' traffic management departments when optimizing P&R. ### Terrain Spatial Perception  
To verify the necessity of considering the built environment and the moderating effects of the built environment when analyzing motorists' P&R behavior in river-valley-type cities, we constructed three models in Table 7. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Model Path** & **Std Estimate** & **Adapt Estimate** & \(\mathbf{p}\) \\ \hline Terrain spatial perception \(\rightarrow\) Security perception & 0.862 & 0.253 & \textless{}0.001 \\ Terrain spatial perception \(\rightarrow\) Convenience perception & 0.868 & 0.254 & \textless{}0.001 \\ Terrain spatial perception \(\rightarrow\) Comfort perception & 0.731 & 0.214 & \textless{}0.001 \\ Terrain spatial perception \(\rightarrow\) Accessibility perception & 0.950 & 0.279 & \textless{}0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Coefficient of second-order confirmatory factor analysis.