Beyond-Design-Basis Evaluation of Advanced Driver Assistance Systems

Simulation studies are nowadays an invaluable tool for the design, as well as for the safety evaluation and verification of Advanced Driver Assistance Systems (ADAS) or Automated Driving Functions (ADF). In case ADAS/ADF are developed using simulation studies, they are (usually) designed to avoid accidents by means of suitable control actuations. However, the safety of those ADAS/ADF depends on the explicit and implicit assumptions made during the design process. If well designed, those assumptions will cover the vast majority of cases that might occur during real world driving. It is hardly possible though to account for all types of thinkable scenarios and accounting for highly improbable cases already during the design process might lead to tremendous additional costs in terms of performance. It is therefore proposed here to use a three layer safety philosophy for ADAS/ADF: The functionalities are designed based on realistic assumptions regarding traffic situations and scenarios. Subsequently, based on a catalog of test scenarios the crash boundary for the newly developed functionality will be identified, i.e. the test case parametrization will be searched for in which it is still possible to avoid a crash. In a last step, those cases for which a crash cannot be avoided will be analyzed with respect to the expected consequences for the people involved. This third step will be referred to as “beyond-design-basis safety assessment” (BDBSA) throughout this paper. A new, easy to apply methodology is proposed here for evaluating the consequences of such unavoidable crash scenarios in BDBSA.