# Data-Driven Test Scenario Generation for Cooperative Maneuver Planning on Highways
## 2 Materials and Methods
### Concept  
The goal in creating the scenario dataset is to provide the possibility of testing different maneuver planners against each other. In terms of methodology, it is therefore advisable to base the scenario generation on the quality criteria of test theory. These comprise objectivity, reliability and validity as main criteria ([15], S. 179) and standardization, economy, and practicability as subsidiary criteria ([16], p. 485 f.). The following section explains how these quality criteria are considered in the concept of test scenario generation. Objectivity: If a test achieves the same results regardless of the person performing it, the test is objective. Since the test in our case represents the execution of a simulation, it is objective if the conditions of the simulation are clearly defined. Therefore, the description of the roadway characteristic, starting position (longitudinal and lane) and initial speed, as well as the duration of the simulation, are determined for each scenario. Reliability: A test that produces the same results in repeated measures is reliable. Since a simulation doesn't underly external influences, as e.g., field tests do, the simulative test of a single scenario is inherently reliable. Because different maneuver planners are better at different scenarios, a reliable comparison must include a large number of diverse situations and varying roadway characteristics, such as differing lane numbers and acceleration lanes. This was taken into account by using a large traffic dataset that was recorded in several locations for the scenario extraction. Validity: In contrast to the model validation domain, where validity refers to the consistency between model and reality, validity in terms of test theory means that a test measures exactly what it is supposed to measure. In the case of cooperative behavior planning, this comprises the metrics used to measure cooperation, the test mode in which the maneuver planners are tested as well as the selection of test scenarios. The applied metrics are the result of a previous work [17] and are presented briefly in Section 2.3. The test mode must ensure that the tested maneuver planners not only behave intelligently in situations where they need the cooperation of other vehicles but also when they are in the position to support others. Therefore, the test mode intends that the maneuver planner being tested is applied to all vehicles of a scenario within the same simulation. For this reason, no trajectory is specified for any of the vehicles, but rather the starting situation. From this starting situation, the maneuver planners are applied until the determined duration of the scenario is reached. In order to be valid for testing cooperative behavior, the test scenarios must benefit from cooperation. In the context of cooperative driving, [PERSON] and [PERSON] [18] state that cooperative behavior affects the utility of the cooperatively acting agent and the utility of at least one other agent in a way that the total utility increases with respect to a reference utility. Furthermore, the cooperative action must be performed intentionally. This concept implies that every scenario needs to be simulated twice, by a reference driver model and by a completely cooperative driver model. We then regard a scenario as valid if at least one vehicle accepts a lower individual utility to increase the total utility in the cooperative solution compared to the solution of the reference model. The individual drawback of at least one vehicle is not a requirement according to the definition of [PERSON] and [PERSON] [18], but in order to imply the intention to increase the other's utility and not only the ego utility, this is a necessary assumption. In the sense of [PERSON] and [PERSON] [18], cooperative actions with an individual drawback of the acting agent are referred to as altruistic-cooperative. Standardization: A standardized test delivers a reference for its test results.