## 5 Discussion  
In this study, statistical differences in driving behavior were investigated using scenarios using log data such as speed and LPM extracted from a VR driving experiment. As a result, it was found that if the acceleration lane is extended at intervals of 20 m from the standard acceleration lane length, the \(S_{difference}\), \(a_{miltc}\), and \(a_{mincit}\) of the ramp vehicle tend to become smaller. Although the driving behavior was not significantly changed in RS scenarios, which are relatively familiar road environments for many drivers, changes in LS scenarios were noticeable. Thus, in the case of the merging section on the left-side on-ramp, there is a need for a larger extra distance than the minimum acceleration lane length for the driver to recognize the traffic environment, change lanes, and enter the main line. The phenomenon of reduced speed at the merging sections we discussed earlier is associated with the driving behavior of checking visually for vehicles driving on the main line. This can also be explained by the gaze ratio based on visual fixation counts obtained from a pair of Tobii Pro Glasses 3 [30], which are a device capable of extracting data on visual behavior worn by the participants in the VR driving experiment. As lane changes are required on the road, all gaze zones visible to the driver's eyes were divided into areas of interest, such as the front window, side mirrors, and inside of the vehicle [31]. A short merging section was divided into approximately 20 m intervals. The change in gaze ratio in the side mirror by direction was analyzed for each section in more detail. Figure 7 shows the average gaze ratio of the right- and left-side mirrors among the visual fixation count data in all front areas. The visual fixation ratio for the right-side mirror in the C and D sections of the acceleration lane was approximately 25% to 40% for LS scenarios. This was relatively higher than the visual fixation ratio for the left-side mirror. In this regard, it is believed that the phenomenon of more decrease in speed in LS scenarios is due to drivers having to turn their heads more to look at the right-side mirror to recognize vehicles driving on the main line. During this short process, the driver naturally slows down while looking longer into the right-side mirror. To compare the acceleration behavior of RS and LS scenarios, we analyzed the two average acceleration rates as analytical indicators. Figure 8 shows the scatter plot of the three analytical indicators, \(S_{difference}\) and \(a_{mintlc}\), or \(S_{difference}\) and \(a_{mincit}\). In the RS scenarios, in contrast to the LS scenarios, there was a relatively larger number of subjects with an \(S_{difference}\) of 0, that is, subjects accelerating without decreasing their speed while entering the acceleration lane. The LS scenarios, such as LS100 and LS120, were found to have a relatively high \(S_{difference}\) and high average acceleration rates. The scatter plot appears long and slanted to the upper right. According to the simple linear regression model for \(S_{difference}\) and \(a_{mincit}\) of LS scenarios, the values of R2 were 0.7988 for LS100 and 0.8598 for LS120, which were relatively high compared to RS scenarios. There was, however, a less consistent tendency in the value of \(a_{minitlc}\) than in the value of \(a_{mincit}\). This indicates  
Figure 7: Average gaze ratio of left- and right-side mirrors. that driver acceleration behavior when changing lanes varies. LS140 is comparable to RS scenarios in terms of \(S_{difference}\) and shows relatively stable trends and values of less than 1.0 m/s\({}^{2}\) in terms of average acceleration. Based on the results of the previous analysis, there was a difference in driving behavior in the merging sections depending on the direction of the ramp. In addition, there was more stability in driving behavior depending on the acceleration lane length.