# An Analysis of Vulnerable Road Users Overtaking Maneuver along the Urban Road
## 4 Discussion
### Driver Behavior  
Overall, the average LPG of a major part of drivers (16/18 \(\sim\) 88.9%) in an urban area in the experiment was less than 1.5 m rule for the rural road. So that, safety systems should have a different threshold for overtaking in an urban area. It is worth notice that the accepted LPG of type A was identical and much larger than others. It seemed that they had changed lanes to avoid the potential collision with VRU.  
The results also uncovered that all types of drivers reduced speed when approaching the VRU, except type D. According to strategy definition [2], most drivers (15/18 drivers) chose accelerative overtaking strategy. It is aligned with the finding of [PERSON] et al. [11]. However, the type D drivers' strategy was flying overtaking, and their average speed were always bigger than the initial speed.  
More details, type B and type C drivers, who were considered as competent groups have various differences in driving style. The average accepted LPG of type B was larger than type C's value. Type B's LPG perception was influenced by the interaction between lane width and initial speed, main effects of lane width, VRU location, while type C's LPG was only affected by lane width of the further road. Moreover, drivers in type B slightly decelerated in the approaching phase, but drivers in type C slightly speeded up before making an overtaking decision. However, their tendencies in regulating the speed had been impacted by the same main factors: the lane width and initial speed while VRU characteristics did not have a statistical effect.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Type A** & **Type B** & **Type C** & **Type D** \\ \hline LPG & **\(\  
Furthermore, the driving styles of type A (conservative style) and type D (aggressive style) drivers are worth noticing. On the one hand, type A drivers always slowed down before making a decision which may cause trouble to traffic flow and kept large LPG to VRU. Lateral gap perception of type A drivers was statistically significantly influenced by lane width of the road, VRU location on the shoulder, and the interaction between lane width and initial speed. Although they always decreased speed, various interactions, and main effects of lane width, initial speed, VRU type still have a significant effect on RMS. On the other hand, type D drivers posed a high risk of collision due to their speeding tendency and small LPG to VRU while overtaking. Their RMS was influenced only by the vehicle's initial speed. Their LPG was affected by the road's lane width and VRU location. In line with [15], the difference between types can be seen far from the passing point, but it is best explained when SUV was at the distance from 40 to 20 m to VRU's passing point. The difference of type A and type D in speed can be recognized even at the distance of 60 m before the passing point.  
Due to various driving styles, there is a need for a personalized assisting system that will enhance driver acceptance with the system's warning and/or response. These pieces of information help design safety systems to warn drivers and intervene in VRU avoidance with regards to driving style, road, and VRU characteristics.