# Data-Driven Test Scenario Generation for Cooperative Maneuver Planning on Highways
## 3 Results
### Scenario Clusters  
For a more detailed understanding of the cooperative mechanisms in the dataset, a clustering of the main cooperative actions is performed. The main cooperative action is the action that the cooperating vehicle (determined by the highest drawback) performs in order to reduce overall costs of the scenario. According to the cooperation metric's cost terms, the drawback can be dominated by higher safety, time, energy or lateral costs. Since braking induces lower velocity, which affects the time metric, the energy costs are not considered separately. The safety metric is also irrelevant because the cooperative planner does not produce unsafe solutions, whereby the safety costs cannot be higher than in the reference solution. The remaining terms are the metrics for time efficiency and lateral maneuvers. Within the time metric, increased costs for the cooperative solution can be caused by higher (V+) or lower (V\(-\)) speed compared to the desired velocity. Additional lateral costs can be induced by a lane change to the left (LCL) or to the right (LCR). The analysis of these scenario clusters delivers the following cooperative mechanisms:  
_LCR:_ The cooperating vehicle performs a lane change to the right. According to the passing-on-the-right prohibition, it enables its follower to pass in the cleared lane. _LCL:_ The lane change to the left clears the initial lane of the cooperating vehicle. Because of the passing-on-the-right prohibition, the cleared lane cannot be used to pass the cooperating vehicle. Instead, the cleared lane becomes the target lane of another vehicle's lane change from the right. Reasons for the enabled lane change of the benefiting vehicle are slower lead vehicles or that the lane ends. _V+:_ The scenario group of cooperation through increased velocity is split into two subgroups. The first one, hereinafter referred to as V+, is characterized by the cooperating vehicle staying in its lane. In this group, the acceleration opens a gap behind the vehicle, which allows a faster following vehicle to have more time for a lane change, enabling it to maintain greater speed (see example scenario). In the second sub group (V+ LCR), the acceleration is followed by a lane change to the right. According to the pure LCR scenarios, the goal of the cooperating vehicle's action is to let a faster vehicle pass. Due to a vehicle on the right lane blocking an immediate lane change, the cooperating vehicle accelerates to overtake the blocking vehicle and to clear the lane as fast as possible to prevent its follower from losing speed. The main difference between the V+ LCR and the LCR group lies in the definition of the cooperative action. Since in the LCR group the cooperative behavior planner performs the LCR in contrast to the reference model, the LCR is the main cooperative action. In the V+ LCR group, both behavior models perform the LCR, and the cooperative action lies in the acceleration to clear the lane earlier. The combination of V+ with a LCL is irrelevant in the computed cooperative solutions. _V\(-\)_: The V\(-\) scenarios are also split into two subgroups. Similar to the V+ group, the distinction can be made based on future lane changes of the cooperating vehicle. In the first subgroup (V\(-\)), the cooperating vehicle decelerates without changing lanes afterward. The deceleration opens a gap in \begin{table}
\begin{tabular}{c c c} \hline \hline
**Behavior Model** & **Range of Velocity** & **Range of Acceleration** \\ \hline Reference model & \(0\,\mathrm{m}\,\mathrm{s}^{-1}\) to \(55.9\,\mathrm{m}\,\mathrm{s}^{-1}\) & \(-9\,\mathrm{m}\,\mathrm{s}^{-2}\) to \(1.4\,\mathrm{m}\,\mathrm{s}^{-2}\) \\ Cooperative model & \(12.8\,\mathrm{m}\,\mathrm{s}^{-1}\) to \(58.4\,\mathrm{m}\,\mathrm{s}^{-1}\) & \(-2.6\,\mathrm{m}\,\mathrm{s}^{-2}\) to \(1.4\,\mathrm{m}\,\mathrm{s}^{-2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Range of velocity and acceleration. front of the vehicle that is used by other vehicles to merge in from the left or the right lane.