## 4 Results and Discussions
### Bayesian Logistic Ordinal Regressions
#### 4.2.1 Results and Analysis of Experiment 1
), MCMC standard error (MCSE), posterior median, and 95% credit interval. Among the characteristic variables in this model, except for drivers' eye height, the MCSE values for all others are less than 0.01, indicating low variability across repeated simulations and, thus, reliable results. The close proximity of the posterior means to the medians for all characteristic variables suggests that the posterior distributions are approximately normal. Furthermore, the fact that the 95% credit intervals for all characteristic factors exclude zero demonstrates a statistically significant correlation between each factor and driver cognitive load. In Table 6, \"omitted\" represents the benchmark value for comparison. A negative fixed effect indicates a higher probability of reducing the time buffer, implying an increased cognitive load for drivers, while a positive effect suggests the opposite. The analysis of the results is as follows:  
1. Driver Behavior:  
The driver's eye height exhibits a strong positive correlation with the time buffer (mean = 2.388042 > 0, 95% CI 1.59 to 3.14), suggesting that within a certain range, a higher eye height is associated with a lower cognitive load. This is presumed to stem from a broader field of vision when the line of sight is higher in a range [44]. 2. Traffic Environment:  
On city roads, the probability of increased cognitive load for drivers is higher under identical scenarios (mean = \(-0.203<0\)). City roads are often constrained by multiple physical obstacles such as buildings, street trees, and traffic facilities, leading to a compressed field of vision for drivers. This limitation not only complicates the perception of potential \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Mean** & **Std. Dev.** & **MCSE** & **Median** &
\begin{tabular}{c} **[95\% Cred.** \\ **Interval**] \\ \end{tabular} \\ \hline Eye Height & 2.388 & 0.402 & 0.055 & 2.388 & 1.586 & 3.142 \\ \hline Distance & \(-0.030\) & 0.003 & 0.000 & \(-0.030\) & \(-0.037\) & \(-0.023\) \\ \hline City Roads & \(-0.203\) & 0.051 & 0.004 & \(-0.203\) & \(-0.302\) & \(-0.104\) \\ \hline Left Lane Changes & 0.152 & 0.056 & 0.003 & 0.151 & 0.043 & 0.266 \\ \hline Low Traffic Flow & 0.839 & 0.075 & 0.009 & 0.838 & 0.687 & 0.987 \\ \hline Medium Traffic Flow & 0.419 & 0.054 & 0.006 & 0.420 & 0.302 & 0.520 \\ \hline Vehicle Type 1 & \(-0.409\) & 0.097 & 0.009 & -0.410 & \(-0.602\) & \(-0.221\) \\ \hline Vehicle Type 2 & 0.429 & 0.087 & 0.006 & 0.431 & 0.259 & 0.595 \\ \hline \hline \end{tabular}  
In this table, expressway, right lane changes, high traffic flow and Vehicle Type 3 are omitted.  
\end{table} 
Table 6: BLOC estimation table of Experiment 1.  
hazards but also necessitates more frequent adjustments in gaze and attention to allow drivers to comprehensively assess and respond to dynamic changes in their surroundings. Additionally, the complexity of city road environments, with pedestrians, non-motorized vehicles, various types of motor vehicles, and intricate traffic signals and signs, contributes significantly to the cognitive load of drivers. Left-lane changing reduces the cognitive load of drivers by 15%, compared to right-lane changing scenarios. Given that blind spot information is concentrated in the driver's right field of view, the driver focuses mainly on the forward area of the target lane during left-lane changing. Consequently, blind spot alerts from the right (non-focal side) are more likely to capture the driver's attention. In right-lane-changing scenarios, the spatial overlap of blind spot images and the driving task (observing the right lane conditions) along the line of sight can create a \"redundant information\" effect, potentially leading to an increase in the cognitive load. In addition, since the driver's seat is located on the left, the road information required when changing to the right lane is farther away from the driver, which is also one of the possible factors that can cause a higher cognitive load.