# An Analysis of Vulnerable Road Users Overtaking Maneuver along the Urban Road
## 3 Results
### Descriptive Data  
Figure 4 showed profiles of sample means and 95-percent confidence interval (95% CI) of population means of the lateral gap from SV to VRU and ratio of SV speed to initial speed for each type of driver. In increasing order, the 95% CI of lateral passing gap means of type D, type C, type B, type A drivers were [0.921, 1.03] m, [1.08, 1.15] m, [1.37, 1.45] m, [1.92, 2.17] m, respectively. The drivers in type B and type C chose to drive closely to the initial speed. Their 95% CI of the ratio of minimum vehicle speed to initial speed were: [0.752, 0.790] and [0.873, 0.889], respectively. Their 95% CI of the ratio of passing speed to initial speed means were: [0.875, 0.935] and [1.05, 1.11], respectively. On the one hand, drivers in type D preferred speeding from the beginning. 95% CI of their ratio of minimum speed and passing speed to initial speed of road were: [0.984, 0.999] and [1.29, 1.39], respectively. On the other hand, type A drivers always reduced speed. Their 95% CI of the ratio of minimum speed to initial speed was [0.592, 0.652]. They passed the VRU at the ratio of passing speed to initial speed mean of 95% CI [0.702, 0.786]. Table 2 provides descriptive statistics of LPG, RMS that outline the data of each group. Figures 5-8 show the box plots related to LPG and RMS for all types in different conditions of lane width, SV's initial speed, VRU type, and location, respectively. Overall, the mean profiles were different for each group of drivers.  
The LPG indicates the safety gap perception of drivers when they overtaking VRU. The upper panel of Figure 4 shows that the average LPG profiles for all four types of drivers were bigger than the gap at the beginning of manual mode. So, drivers, normally do not ignore the existence of VRU even when they were in the walking/cycling lane. Despite type B's gap profile gradually increased from the beginning, the gap profiles of others started increasing when longitudinal displacement from SV to VRU was about 40 m.  
The lower panel of Figure 4 shows, on average, how the drivers regulate the vehicle speed in comparison to the initial speed. The graphs reveal the speeding tendency of type D drivers. They accelerated from the beginning of the manual mode. The type A drivers were in the opposition, always reduced the speed. While type B and type C drivers maintained their speed. The ratio of SV speed to initial speed indicates overtaking strategy of drivers. From those profiles, only the type A drivers chose the accelerative overtaking strategy.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Metrics** & **Type A** & **Type B** & **Type C** & **Type D** \\ \hline LPG [m] & 2.05 (0.57) & 1.41 (0.38) & 1.12 (0.32) & 0.98 (0.34) \\ \hline RMS & 0.62 (0.13) & 0.77 (0.17) & 0.89 (0.11) & 0.99 (0.04) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Descriptive statistics (mean, standard deviation) for each driver group.  
Figure 4: Profiles of sample means (lines) and 95% confidence interval (95% CI) of population means (shade) of the lateral gap from SV to VRU (**a**) and the ratio of SV velocity to initial speed (**b**) over longitudinal displacement for each group of drivers.  
Figure 5: Box plots of the minimum lateral gap while passing VRU (**a**) and the ratio of SV’s minimum velocity to initial speed while approaching VRU (**b**), grouped by road’s lane width between driver’s groups.  
Figure 6: Box plots of the minimum lateral gap while passing VRU (**a**) and the ratio of SV’s minimum velocity to initial speed while approaching VRU (**b**), grouped by initial speed between driver’s groups.  
Figure 8: Box plots of the minimum lateral gap while passing VRU (**a**) and the ratio of SV’s minimum velocity to initial speed while approaching VRU (**b**), grouped by VRU’s location between driver’s groups.  
Figure 7: Box plot of the minimum lateral gap while passing VRU (**a**) and the ratio of SV’s minimum velocity to initial speed while approaching VRU (**b**), grouped by VRU’s type between driver’s groups.