# Faudistic Platooning: Subdivide Platoons, Unite Networks, and Conquer Efficiency and Reliability
## 5 Results
### Simulation Scenario  
Vehicles travel on a motorway supported by one single cell of a cellular network. All vehicles continuously transmit CAMs. Table 1 summarizes chosen the simulation parameters: a vehicle drives with a _constant speed_ of 30 m s\({}^{-1}\) and no situations worthy of announcement occur. Hence, no DENMs are transmitted. The platoon is formed decentralized according to [20]. Once platooned, vehicles perform _Feudalistic Platooning_. To do so, the twelve vehicles group into four equally sized vassalages, each consisting of one lord, one knight, and one merchant. During the simulation, the vassalage size is not adjusted. As _merchant interval_, we select 1 s, i.e., the greatest possible interval in which a vehicle is transmitting CAMs, with the effect that vehicle state data from the preceding vassalage could be considered for vehicle control if necessary. Data from vassalages further upstream are less critical in terms of time: on the one hand, data may not be relevant for the selected control policy. On the other hand, the spatial distance is increased as at least one vassalage is in between. Thus, the _shipping interval_ and _ordering interval_ should be selected according to control needs and may be dynamically and individually adapted based on proximity to the relevant vehicle, e.g., the leading vehicle. In this scenario, a static interval of 2 s is used for both shipping and ordering. _Intra-Vassalage Vehicle Distance_ is small enough that a vassalage cannot be divisible by the surrounding traffic: [PERSON] et al. [40] showed that for a successful lane change on a freeway, the lead and lag gap combined need to be at least 0.27 s. Furthermore, the length of the cutting vehicle has to be added. Neglecting the latter and at our speed, this would result in a minimum gap of 8.1 m. The distance between two vehicles of different vassalages (_inter-vassalage vehicle distance_) must be kept sufficiently large to allow surrounding traffic to use the gap when necessary, e.g., to reach the breakdown lane. The median for accepted gap lengths is 2.26 s [40], corresponding to 67.8 m. Thus, we select 70 m as the gap between two vassalages.  
Although in the presented simulation scenario, the _intra_- and _inter-vassalage vehicle distance_ are statically selected, distance between vehicles may be dynamically adapted: dynamic platooning within and between vassalages accounts for environmental changes [20] and may increase or decrease the gap once needed or possible.  
Figure 7 shows the platoon after a successful synchronization process: the vehicle colors indicate their roles. The depicted scenario shows inter-vehicle distance adaptations  
\begin{table}
\begin{tabular}{l r r} \hline \hline
**Parameter** & **Value** & **Unit** \\ \hline Simulation Time & 300 & s \\ Merchant Interval & 1 & s \\ Ordering Interval & 2 & s \\ Shipping Interval & 2 & s \\ Constant Speed & 30 & m s\({}^{-1}\) \\ Platoon Length & 12 & number of vehicles \\ Vassalage Size & 3 & number of vehicles \\ Packet Reception Rate & 100 & \% \\ Intra-Vassalage Vehicle Distance & 8 & m \\ Inter-Vassalage Vehicle Distance & 70 & m \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameters used for the presented results.  
caused by _Fendalistic Platooning_: while gaps between vassalages start to increase, gaps between vehicles of the same vassalage start to decrease.