# Priority of Emergency Vehicle Dynamic Right-Of-Way Control Method in Networked Environment
## 4 Conclusions  
An equal right-of-way does not guarantee the efficiency and safety of EVs and has a large impact on CVs. While priority for the special right-of-way largely improves the efficiency of EV operations, it also greatly increases CV delays and does not guarantee the overall operational efficiency of the roadway. The PDR-EVs method proposed in this paper  
Figure 13: Impacts of CVs and EVs operations on the net income of the system: (**a**) CV flow and (**b**) length between EV buffers. realized the EV's dynamic priority right-of-way in the vehicle infrastructure cooperation environment. Priority was given to EVs by setting two dynamic variable intervals: the non-intrusive interval and the buffer interval. This approach can also reduce delays for CVs to a certain extent. The main conclusions are summarized as follows:  
1. The PDR method could reduce EV delay by more than 70% on average without increasing the CVs' delay (no more than 8%), and its control effect was highly sensitive. The overall EV delay was improved when the CV flow was high, thus revealing that the dynamic right-of-way control method is unsuitable for high saturation (greater than 0.8). In high saturation, the length between the buffers must be reduced to improve the EV's operating efficiency, but the effect is not great. Therefore, it is extremely difficult to evacuate other vehicles on high-saturated road sections to enhance the operating efficiency of the EVs. Cooperation with management and control through other methods, such as upstream-induced diversion, is necessary. 2. In the context of the PDR approach, CVs of the outer lanes frequently change lanes to the inner lanes, which disturbs the stability of the homogeneous traffic flow (both CVs) in the inner lanes. The inappropriate lane-changing behavior directly destroys the original stable vehicle group in the inner lane, thereby resulting in local deceleration of the traffic flow on the road section and reducing the system's operating efficiency. Therefore, implementing the PDR-EVs control method should be combined with adjusting the lane change rate to ensure the operating efficiency of the EVs and, at the same time, to affect the normal operation of CVs as little as possible. 3. EVs can dynamically adjust the length of the non-intrusive zone and the buffer zone in real-time according to the speed of the preceding vehicle and road traffic conditions. When the CV traffic is high, the length of the buffer zone can be reduced. A short buffer zone is suitable for high-traffic conditions, and a long buffer zone is suitable for low-traffic situations. The buffer zone size can be flexibly changed and applied to scenarios with various CV traffic. 4. The PDR method can reduce EV driving resistance and is not limited by the speed of the social vehicle. By employing the PDR method, EV running stability is almost close to the PSR and can run at the desired speed. Compared with the ER method, the PDR method can improve the traffic capacity of the road section. The PDR method is a control method that considers the operating efficiency of EVs and CVs and has the best overall performance. 5. The model does not quantitatively consider the relationship between the vehicle speed and the vehicle-following distance. Therefore, it is necessary to perform quantitative function analysis on the length of the non-intrusive interval, the length of the buffer zone, and the vehicle speed to optimize the car-following behavior to improve the operating efficiency and calibration. The issue of right-of-way priority under high saturation conditions and research on EV marshaling driving should also be considered. In the experimentation, the length of the non-invasive interval of the EV's front end remained unchanged and was not discussed. The main purpose was to simplify the model and the experimental process. Using it as a fixed value for experiments can also relatively objectively reflect EV operating rules in various scenarios without affecting the scientific nature of the conclusions. Conceptualization, Z.K.