## 5 Results and Discussion  
### Cluster Analysis  
#### 5.1.1 Latent Profile Cluster Identification  
The LPA was performed using the Mplus software (version 7.0). Model fit information was examined to determine the number of clusters, as shown in Table 6. As depicted in Table 6, the results of AIC, BIC, aBIC declined with the increase in the cluster number, while the decreasing trends of the three criteria turned out to be gentle after three clusters. Also, the three clusters' LMR < 0.05 and the entropy approached 1. As indicated by the above result, three was the satisfying cluster number for this study. Hence, the human drivers fell into three clusters for their psychological characteristics when facing CAVs. The scores of the observed variables for the different clusters are graphically presented in Figure 1. Moreover, the mean and variance of the five latent variables (i.e., FA, TR, ATT, RP, and PBC) were investigated in depth based on the analysis of variance (ANOVA) from Table 7. The results further confirmed that significant differences were reported among the three clusters in the latent variables, suggesting reasonable latent profile analysis results. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Scenario** & **Diagram** & **Behavior Choice** \\ \hline \hline \multirow{4}{*}{1.Driving behind a CAV when the front vehicles on the adjacent roads are HDVs.} & \multirow{4}{*}{\begin{tabular}{c} Keep following the CAV. \\ Change lanes when meeting the appropriate lane-changing gap, \\ and drive behind the HDV. \\ Regardless of the type of front vehicle, if the driving demand \\ cannot be met (the speed of the front vehicle is too low, falling \\ below the expected speed, or the distance to the front vehicle does \\ not meet the driver’s desired following distance), the intention of \\ changing lanes will be generated; otherwise, I will continue to drive \\ on the current lane. \\ \hline \multirow{4}{*}{2. Car-following distance when driving behind a CAV than driving behind an HDV.} & \multirow{4}{*}{\begin{tabular}{c} Increase the car-following distance. \\ No difference if the leading vehicle is HDV. \\ Reduce the car-following distance. \\ \end{tabular} } \\  & & \\ \hline \hline \end{tabular} \begin{tabular}{c} 3. The speed of the preceding vehicle is low, and you have generated the intention to \\ changing lanes. At this \\ moment, a platoon of CAVs is \\ driving on the target lane. \\ \hline \multirow{4}{*}{4. Suppose you are driving the white vehicle and have \\ decided to change lanes. \\ When the leading vehicle on \\ the target lane is a CAV, \\ comparing with the HDV, \\ what are your requirements \\ for the vehicle spacing? \\ \hline \multirow{4}{*}{5. Suppose you are driving the white vehicle and have \\ decided to change lanes. \\ When the leading vehicle on \\ the target lane is a CAV, \\ compared with the HDV, \\ are your requirements for the \\ vehicle spacing? \\ \hline \hline \end{tabular} \begin{tabular}{c} 4. Suppose you are driving the \\ white vehicle and have \\ decided to change lanes. \\ When the leading vehicle on \\ the target lane is a CAV, \\ compared with the HDV, \\ are your requirements for the \\ vehicle spacing? \\ \hline \hline \end{tabular} \
\begin{tabular}{c} 5. Suppose you are driving the \\ white vehicle and have \\ decided to change lanes. \\ When the leading vehicle on \\ the target lane is a CAV, \\ compared with the HDV, \\ are your requirements for the \\ vehicle spacing? \\ \hline \hline \end{tabular}
\begin{tabular}{c} 6. Increase the requirements for the vehicle spacing compared with \\ the leading vehicle on the target lane is an HDV. \\ No difference with the leading vehicle on the target lane is an HDV. \\ Reduce the requirements for the \\ leading vehicle on the target lane is an HDV. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The hypothetical scenarios when driving in mixed traffic.