## 3 Results
### Subjective Evaluation  
In order to explore the impact of driving style, driver distraction state and warning timing on the utility of LDW systems comprehensively, the driver's subjective evaluation was analyzed for the LDW system, and the technology acceptance model was constructed [35; 36]. The five-level Likert scale was used as the questionnaire to investigate the acceptance of the LDW system for different styles of drivers after the simulation driving tests. The statistics of responses from the scales are shown in Figure 8 (1 = not at all, 2 = slightly, 3 = somewhat, 4 = moderately, 5 = a lot) [34]. The mean score (MS) represents \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Driving Style** & **Influence Factor** & \(\beta\) & **Exp(\(\beta\))** & **SE** & \(p\) \\ \hline \multirow{4}{*}{Cautious} & \multirow{2}{*}{No ST} & early/no warning & 0.089 & 1.156 & 0.402 & 0.501 \\  & & late/no warning & 0.432 & 1.846 & 0.355 & \textless{}0.001 \\  & & early/no warning & 0.016 & 1.082 & 0.472 & 0.832 \\  & & late/no warning & 0.721 & 2.438 & 0.549 & \textless{}0.001 \\  & & early/no warning & 0.162 & 1.498 & 0.432 & 0.243 \\  & & late/no warning & 1.878 & 5.353 & 0.407 & \textless{}0.001 \\  & & early/no warning & 1.010 & 3.926 & 0.601 & \textless{}0.001 \\  & & late/no warning & 0.683 & 2.294 & 0.496 & \textless{}0.01 \\ \hline \multirow{4}{*}{Moderate} & \multirow{2}{*}{No ST} & early/no warning & 0.046 & 1.123 & 0.370 & 0.516 \\  & & late/no warning & 0.320 & 1.726 & 0.356 & 0.012 \\  & & early/no warning & 0.031 & 1.108 & 0.351 & 0.525 \\  & & late/no warning & 0.534 & 2.039 & 0.344 & \textless{}0.001 \\  & & early/no warning & 0.675 & 2.251 & 0.400 & \textless{}0.001 \\  & & late/no warning & 0.542 & 2.091 & 0.352 & \textless{}0.001 \\  & & early/no warning & 1.652 & 5.021 & 0.550 & \textless{}0.001 \\  & & late/no warning & 0.362 & 1.792 & 0.447 & 0.007 \\ \hline \multirow{4}{*}{Aggressive} & \multirow{2}{*}{No ST} & early/no warning & \(-0.910\) & 0.834 & 0.409 & 0.037 \\  & & late/no warning & 0.341 & 1.742 & 0.044 & 0.016 \\  & & early/no warning & 0.015 & 1.068 & 0.484 & 0.534 \\  & & late/no warning & 0.615 & 2.193 & 0.433 & \textless{}0.001 \\  & & early/no warning & 0.132 & 1.350 & 0.396 & 0.318 \\  & & late/no warning & 1.573 & 3.861 & 0.547 & \textless{}0.001 \\ \cline{2-6}  & & early/no warning & 0.844 & 2.619 & 0.557 & \textless{}0.001 \\ \cline{2-6}  & & late/no warning & \(-0.332\) & 0.317 & 0.532 & 0.049 \\ \hline \hline \end{tabular} Note: The no warning is the dummy variable, e.g., “early/no warning” represents early warning timing compared to the no warning condition.  
\end{table} 
Table 4: Parameter of COX model. the overall rating and was used to quantify the overall acceptance of drivers for the LDW system. MS\({}_{e}\) and MS\({}_{l}\) represent the mean score under early and late warning, respectively. Under the no ST condition, it can be seen that the acceptance of early or late warning was lower than 3 points (out of 5 points), while the acceptance was significantly higher under the ST condition, with a MS higher than 3 points accounting for 72.2%. This implies that drivers will maintain a higher level of alertness under the no-distraction condition, and the warning was prone to cause resentment and reduce the driving comfort. Under the low-level ST condition, the overall rating of the early warning was higher for cautious drivers, suggesting that cautious drivers had a higher acceptance of early warning (MS\({}_{e}\) = 3.86, MS\({}_{l}\) = 3.08). As for the moderate and aggressive drivers, the overall rating of late warning was higher, suggesting that the majority of these drivers were more receptive to late warnings (MS\({}_{e}\) = 3.16, MS\({}_{l}\) = 3.73 for moderate drivers; MS\({}_{e}\) = 2.90, MS\({}_{l}\) = 3.61 for aggressive drivers). It can be inferred that when the driving loads were lower, these two types of drivers could devote more attention to perceiving lane departure risk, leading to higher acceptance of late warnings.