## 3 Results  
### Characterization Results  
Characterization refers to an indicator's ability to adequately describe or reflect the essential attributes and states of an object. It illustrates the correlation and significance of an indicator in describing, assessing, or predicting something. The significant results of the characterization analysis of the EEG indicator are shown in Table 2. Under manual driving, multiple channels demonstrated statistical significance (\(p<0.05\)) in the Theta band and Theta/Alpha ratio. This result suggests an increased cognitive load and information processing activity in the brain during driving tasks that require high levels of vigilance. Under automated driving, except for the P3 and P7 channels of the Alpha band, which demonstrated significance, all other frequency bands and channels were not significant (\(p>0.05\)). This indicates that in the high vigilance state, the activity in brain regions typically associated with relaxation and attention dissociation is reduced. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Channel**} & \multicolumn{2}{c}{**Theta**} & \multicolumn{2}{c}{**Alpha**} & \multicolumn{2}{c}{**Low Beta**} & \multicolumn{2}{c}{**Theta**} \\ \cline{2-9}  & **Manual** & **Auto** & **Manual** & **Auto** & **Manual** & **Auto** & **Manual** & **Auto** \\ \hline P2 & 0.036 \({}^{*}\)\(\uparrow\) & 0.337 & 0.804 & 0.092 & 0.452 & 0.433 & 0.017 \({}^{*}\)\(\uparrow\) &  
The significant results of the characterization analysis of the eye movement indicator are shown in Table 3. Under manual driving, the head heading deviated significantly to the left in the high-vigilance state compared to the low-vigilance state. Specifically, the median head heading was close to 0 degrees (looking straight ahead) in the low-vigilance state, while it showed a slight leftward deviation in the high-vigilance state. Under automated driving, the pupil diameter was significantly increased in the high-vigilance state compared to the low-vigilance state, indicating a higher cognitive load during high vigilance. The significant results of the characterization analysis of the ECG indicators are shown in Table 4. The results indicate that SDNN, RMSSD, and N50 significantly decrease with increasing driver's vigilance in both manual and automated driving. This decrease usually reflects reduced parasympathetic activity or increased sympathetic activity, implying that the driver's heart is more directly responsive to external stimuli. Based on the comprehensive analysis of the results, In the manual driving mode, EEG indicators related to driver vigilance were primarily concentrated in the parietal and occipital regions. As driver vigilance increased, significant activation was observed in brain regions associated with spatial perception, motor coordination, and visual information processing. In contrast, during automated driving mode, vigilance-related EEG indicators were concentrated in the Alpha band power in the parietal region. Increased driver vigilance in this mode was reflected by significant activation in regions associated with spatial perception. A comparison of EEG signal characteristics between the two driving modes reveals that brain regions related to spatial perception exhibit significant representation of driver vigilance across both modes. However, brain regions associated with motor coordination and visual information processing did not show significant representation of driver vigilance in the automated driving mode. Analysis of eye movement indicators showed that in manual driving, driver vigilance was more strongly related to head movement indicators, while in automated driving, changes in pupil diameter were more closely related to vigilance. The analysis of ECG indicators revealed that parasympathetic nervous system activity decreased as driver vigilance increased in both driving modes.