## 3 Methodology
### Data Analysis  
It is desirable to conduct a comparative evaluation rather than giving absolute meaning to the experimental results because the driving simulation does not perfectly reflect reality. For this purpose, this study defined a flat tangent road section without horizontal and vertical curves as the baseline condition to be compared. The rate of change of the safety indicator found from the target analysis road section compared to the baseline, which is shown as Equation (1), is used as the evaluation index. It is then determined that the driving safety of mixed car-following pairs with a large change rate of the evaluation index would be reduced. Selected safety indicators include the acceleration noise, the standard deviation of lane positions (Std.LP), and the average headway to evaluate the longitudinal driving safety, lateral driving safety, and inter-vehicle safety, respectively. \[\Delta x=\frac{|x_{baseline}-x_{s}|}{x_{baseline}}\times 100\% \tag{1}\]  
where \(\Delta x\) is defined as the rate of the safety indicator compared to the baseline, \(x_{baseline}\) is the evaluation index of the baseline, \(x_{s}\) is the safety indicator found from section \(s\), and \(s\) is the number of sections (1, 2, \(\cdots\), \(S\)). Acceleration noise has been effectively used to evaluate the longitudinal driving safety of vehicles. The standard deviation of acceleration refers to the degree of variance of speed change [29]. A higher acceleration noise value negatively affects traffic safety. Increased  
Figure 7: Conceptual illustration of MADS experiments. acceleration noise indicates that there is decreased driving safety. The acceleration noise can be found using Equation (2). \[AN^{i}(s) =\sqrt{\frac{\sum_{p=1}^{P}\left(\frac{a_{p}^{i}(S)-\overline{a^{i}(s)} }{P}\right)^{2}}{\overline{AN}(s)=\frac{\sum_{i=1}^{P}AN^{i}(s)}{I}}} \tag{2}\]  
where \(AN^{i}(s)\) is defined as the acceleration noise at section \(s\) for driver \(i\), \(\overline{AN(s)}\) represents the average acceleration noise at section \(s\), \(a_{p}^{i}\) represents acceleration at position \(p\) for driver \(i\), \(\overline{a}\) represents the average acceleration noise, and \(i\) represents driver ID (1, 2,..., _I_). Lateral driving safety represents the safety of the vehicle in a direction perpendicular to the driving direction. Lateral driving safety can be evaluated by identifying whether the vehicle travels well along the centerline of the lane when driving in a curved road section. The lane position is defined as the distance from the center of the lane to the center of the vehicle in this study. The value of the lane position is 0 when the center of the lane coincides with the center of the vehicle. The lane position is collected as a (\(-\)) value when the vehicle is driving on the left side of the lane center. The lane position is collected as a (\(+\)) value when the vehicle is driving on the right side of the lane center. The absolute value of the lane position is used for the driving safety evaluation. The Std.LP is the deviation of the lane position from the center of the lane. The higher the Std.LP, the higher the variance of the vehicle position. This indicator has been widely used for lateral safety evaluation [30; 31]. The Std.LP can be found using Equation (3). When the rate of change of the Std.LP in the analysis section compared to the baseline is positive, it means that the driving safety deteriorates compared to the baseline. \[Std.LP^{i}(s)=\sqrt{\frac{\sum_{p=1}^{P}\left(LP_{p}^{i}(s)-\overline{LP^{i}(s )}\right)^{2}}{P}} \tag{3}\]  
where \(Std.LP^{i}(s)\) is defined as the standard deviation of the lane position at section \(s\) for driver \(i\), \(LP_{p}^{i}\) represents the lane position at position \(p\) for driver \(i\), and \(\overline{LP}\) represents the average lane position. Headway represents the time from the point where the front bumper of the preceding vehicles has passed to the vehicle head of the subject vehicle in the car-following situation.