sufficient reaction time is approxi

sufficient reaction time is approximately 400 m. Thus, a rough estimation indicates that a deployment of technology with a communication range reaching 1000 m could be sufficient.According to Oh et al. [32, threeperformance classes forthe VANET applications can be established. Considering the scale of the reaction time and the required communication range, the PEEV-WS falls under the high frequency and low latency performance class, implying a required message generation frequency of about 1 s.2.2. InteroperabilityInteroperability is achieved when components of the system can communicate properly [33]The choice of the VANET technology, which is supposed to be available in cars, implies that all vehicles should comply with IEEE 802.11p-based physical and medium access communication layers [34] and with Internet Protocol-based network layer. Moreover, vehicles should be capable of fully processing messages generated by the proposed system.2.3. VersatilityThere is a potential to utilize PEEV-WSin an extended context. For example, it could support a communication with traffic lights, or coordination of EVs. To consider this possibility in the simulation model, additional data fields carrying general data and thus left for future use were included in the message format.2.4.Information ReleanceIf the PEEV-WS messages were broadcasted, it would be difficult to judge if the message content, often a request to take an action, is relevant for the message recipient. For example, an EV sends a request to a vehicle that is interfering with an EV's trajectory. If the message is broadcasted, then all the vehicles in the communication range receive the message, so the vehicles need additional information to evaluate if they interfere with the EV's trajectory. Buchenscheit et al. [16]proposed to communicate a segment of the EV's route to other vehicles on the road. This can certainly solve theproblem, but it introduces a risk that this sensitive data could potentially be abused. The solution adopted in this paper is to let an EV to determine who is interfering with its future trajectory and to select the specific and relevant communication targets only. Vehicles equipped with the VANET communication modules are exchanging cooperative awareness messages(CAMs) containing their instantaneous position, speed, heading, acceleration, and other parameters. This information can be used by an EV to identify a prospectively interfering vehicle. A routing protocol can then be used to find a communication route to the relevant vehicle.2.5. SecurityThe PEEV-WS messages have to be secured to avoid the riskof fraudulentuse. Securityof yehicular communication itself is a complex and evolving topic, hence, it is difficult to cover it comprehensively within the scope of this paper. Considering [25], we adjust a communication message length of the proposed system to account for the use of future authentication and integrity check mechanisms. Therefore, the length of the communication message in the simulations was set to 300 B.2.6.PrizacCyThe intended transport route and instantaneous position ofthe EV shouldnot be publicly disclosed. In the proposed approach, a risk of misusing this information is minimized by replacing broadcasting by communicating the potentially sensitive messages to the relevant vehicles only. By design, it is the EV's responsibility to decide for which vehicle the message is relevant and to disseminate the information about the expected time and transport infrastructure to be used (e.g., emergency lane).