# Coordinated Control Method of Bus Signal Priority and Speed Adjustment Based on Stop-Skipping
## 5 Case Analysis
### Analysis of Results
#### 5.2.3 Stage 3--Collaborative Control Scheme  
The result of the signal-priority decision in Section 5.2.2 was combined with speed adjustment to carry out cooperative control and quantitative analysis. (1) Signal-priority scheme (section i, iii):  
When the vehicle arrived at the intersection and the time is in the red-light state (Sections i, iii), the bus phase was activated in advance by compressing the non-transit phase to achieve the purpose of bus priority. At this time, the program fed back the passable state of the vehicle at the station before the intersection, and fed it back to the signal device: the green light was extended (GE) when the vehicle arrived at the Section i; the red light was used to truncate (RT) early when the vehicle arrived at Section iii. According to Equation (23), the vehicles V\({}_{3}\) and V\({}_{6}\) arrive at the intersections O\({}_{2}\) and O\({}_{1}\), respectively, and are located in the Section i. According to Equation (27), it is determined that the extended green-light times of vehicles V\({}_{3}\) and V\({}_{6}\) at intersections O\({}_{2}\) and O\({}_{1}\) are 5.46 s and 4.5 s, respectively, as shown in Figure 9a. According to Equation (25), the vehicles V\({}_{2}\) and V\({}_{6}\) arrive at the intersections O\({}_{1}\) and O\({}_{3}\), respectively, and are located in Section iii. According to Equation (29), it is determined \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Vehicles** & **Intersections** & **O\({}_{1}\)** & **O\({}_{2}\)** & **O\({}_{3}\)** \\ \hline V\({}_{1}\) & iv & iv & ii \\ V\({}_{2}\) & iii & iv & iv \\ V\({}_{3}\) & ii & i & iv \\ V\({}_{4}\) & iv & ii & ii \\ V\({}_{5}\) & ii & ii & iv \\ V\({}_{6}\) & i & iv & iii \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Time period of vehicles arriving at each intersection before optimization. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Vehicles** & **Intersections** & **O\({}_{1}\)** & **O\({}_{2}\)** & **O\({}_{3}\)** \\ \hline V\({}_{1}\) & 0 & 0 & 1 \\ V\({}_{2}\) & 0 & 0 & 0 \\ V\({}_{3}\) & 1 & 0 & 0 \\ V\({}_{4}\) & 0 & 1 & 1 \\ V\({}_{5}\) & 1 & 1 & 0 \\ V\({}_{6}\) & 0 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Signal-priority decision results. Figure 9: Signal-priority method at intersections. (a) Section i; (b) Section iii. that the red-light times of vehicles V\({}_{2}\) and V\({}_{6}\) at the intersections O\({}_{1}\) and O\({}_{3}\) are shortened by 4.5 s and 5.4 s, respectively, as shown in Figure 9b. 2. Speed-adjustment scheme (section ii)  
When the vehicle arrives at the intersection and is in the red-light Section ii, the program feeds back to the vehicle for speed adjustment at the station before the intersection. The vehicle accelerates or decelerates at the station before the intersection by integrating GPS and IMU information [43; 44; 45], so that the vehicle can pass through the intersection without waiting (see Table 8). The vehicle decelerates or accelerates after passing the intersection, so that the time remains unchanged when reaching the next station. According to Equation (30), the vehicle accelerates at the station before the intersection; otherwise, it decelerates. From the parameters in Section 5.1, it can be seen that the vehicle accelerates at the station S\({}_{3}\) before the intersection O\({}_{1}\), decelerates at the station S\({}_{6}\) before the intersection O\({}_{2}\) and accelerates at the station S\({}_{9}\) before the intersection O\({}_{3}\). The schematic diagram of the speed adjustment of vehicles arriving at intersections O\({}_{1}\)-O\({}_{3}\) is shown in Figure 10.  
According to Equations (31) and (32), it is determined that the speed of V\({}_{3}\) is 10.65 m/s after the speed increases at the station S\({}_{3}\), and the decelerati  
Figure 10: Schematic diagram of speed adjustment at intersections. (**a**) Intersection O\({}_{1}\); (**b**) intersection O\({}_{2}\); (c) intersection O\({}_{3}\).