ISO 26262

ISO 26262 is a functional safety standard for automotive systems and a derivative of the generic IEC 61508 standard for electrical / electronic / programmable electronic ("E/E/PE") systems. It defines an automotive safety lifecycle's phases and their associated activities and uses a risk-based approach to determine Automotive Safety Integrity Levels (ASILs) and the relevant requirements. An analysis of the system's functions focuses on the potential hazards in the event of a failure, and the consequences to life and property. The computed ASIL ranges from A (least critical) to D (most critical) and takes into account the estimated probability of the failure being exposed, whether the driver can ameliorate the hazard in response, and the severity of the hazard's occurrence.

ISO 26262 specifies requirements for tool qualification, recognizing the benefits from automation in terms of both productivity and accuracy, and defines four tool qualification methods:

  • Increased confidence from use,
  • Evaluation of the tool development process,
  • Validation of the software tool, and
  • Development in accordance with a safety standard.

Qualification is based on the calculated Tool Confidence Level (TCL), ranging from 1 (lowest) to 3 (highest). A tool’s TCL is in turn determined by whether / how an error in the tool or its output can lead to a safety hazard (the “Tool Impact”), and the probability of preventing/detecting such errors (“Tool Error Detection”). A tool at TCL1 does not need qualification. TCL2 and TCL3 tools require qualification, with the system’s ASIL determining which qualification methods are most recommended. Tool qualification artifacts include a Software Tool Qualification Plan, Software Tool Documentation, a Software Tool Classification Analysis (which establishes the relevant TCL), and a Software Tool Qualification Report.

AdaCore's GNAT Pro compiler, CCG, and SPARK Pro verification tool received TCL3 qualification under ISO 26262. All three products have been certified by TÜV SÜD, an independent, globally recognized organization which confirms that products meet national and international standards. The TÜV SÜD certification mark is widely acknowledged and respected as a trusted symbol of quality, safety, and sustainability.