In recent years, trials of autonomous shuttle vehicles have been conducted worldwide. Currently, there exists no generalized process model for deployment and continuous operation of shuttles. Shuttle suppliers use their own developed procedures, making it difficult for the relevant stakeholders (e.g., public authorities) to assess the risk of potential shuttle deployment. The Digibus® Austria flagship project, among other goals, develops an approach for the virtual risk assessment of identified critical spots along proposed shuttle paths. Embedded into the deployment process, this serves as a significant body of evidence for safety assurance in shuttle deployment. Conducted simulation studies optimizing the shuttle’s trajectory for concrete maneuvers, along with derived requirements for the associated virtual environment, are part of the first noteworthy outcomes. Concretely, the developed virtual environment is integrated in the framework used for virtual validation. The framework is then used for a detailed evaluation of a right-turn maneuver, analyzing possible shuttle trajectories. Considerable differences in sensor coverage at the shuttle’s stopping point can be shown. Conclusively, by utilizing the shuttle’s restricted operational domain, the proposed virtual risk assessment is considered the first step toward a general procedure for the safety assurance of automated vehicles.

Automated Vehicles aim to increase road safety as automated driving systems (ADS) take over the human driving task in the operational design domain (ODD), introducing severe challenges for safety validation. Pure driving over many kilometers to gather enough evidence for a safety argument is not feasible. Scenario-based testing is an approach to overcome this, but challenges like parameter discretization still prevail, hindering safety assurance. This work proposes contributions towards a traceable and efficient safety argumentation for ADS built upon ODD coverage. First, ODD coverage is thoroughly quantified across all scenario levels, assuming distribution functions' availability for the scenario parameters. Secondly, a sampling method for n-dimensional scenario parameter distributions is proposed. The provided algorithms adapt an initial k-means clustering using pre-defined boundary conditions requiring significantly fewer scenarios. Furthermore, a risk metric for urban intersections is presented for scenario evaluation. The risk metric consists of two parts, scene prediction of traffic participants (TPs) and risk assessment. The scene prediction uses a manoeuvre-based motion model with a data-driven approach towards trajectory prediction, increasing the validity. For the risk assessment, a probabilistic risk prediction for the TPs is performed for each scenario scene. The risk metric shows a reasonable tradeoff between sensitivity and specificity, outperforming time-to-collision. These contributions are exemplarily applied at an intersection using a simplified setup for generating TPs and ego vehicle trajectories. The results indicate that an increased safety argumentation is enabled using the proposed methods alongside a coverage process, facilitating further research.

Virtual testing using simulation will play a significant role in future safety validation procedures for automated driving systems, as it provides the needed scalability for executing a scenario-based assessment approach. This article combines multiple essential aspects that are necessary for the virtual validation of such systems. First, a general framework that contains the vital subsystems needed for virtual validation is introduced. Secondly, the interfaces between the subsystems are explored. Additionally, the concept of model fidelities is presented and extended towards all relevant subsystems. For an automated lane-keeping system with two different definitions of an operational design domain, all relevant subsystems are defined and integrated into an overall simulation framework. The resulting difference between both operational design domains is the occurrence of lateral manoeuvres, leading to greater demands of the fidelity of the vehicle dynamics model. The simulation results support the initial assumption that by extending the operation domain, the requirements for all subsystems are subject to adaption. As an essential aspect of harmonising virtual validation frameworks, the article identifies four separate layers and their corresponding parameters. In particular, the tool-specific co-simulation capability layer is critical, as it enables model exchange through consistently defined interfaces and reduces the integration effort. The introduction of this layered architecture for virtual validation frameworks enables further cross-domain collaboration.

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