An STPA-Based Analysis of Automated Driving Systems Fleet Maintenance Activities

Automated Driving Systems (ADS) are complex systems composed of several sub-systems whose interaction may lead to emerging properties and unintended behaviors. The expected deployment of vehicles equipped with SAE Level 4 (L4) ADS for Mobility as a Service (MaaS) in the medium future requires a thorough operational safety analysis. The application of risk assessment methods to ADS technologies has been mostly limited to hazards originating from hardware or software malfunctions. Nevertheless, risk analyses of complex systems must also include organizational safety and human-related issues, as they are crucial in ensuring ADS operational safety and gaining the public's trust [1], [2]. In particular, MaaS operations add safety aspects that require appropriate methodologies to be addressed, such as passengers' behavior, fleet operators, and communication between fleet operators, ADS developers, and ADS vehicle manufacturers.