Defining the SOC for an AS requires a judgement of what is considered “sufficiently safe” operation. This is a complex judgement that will require consideration of legal and ethical factors ,  as well as the risk tolerance of the identified stakeholders for the AS operation. Determining and justifying the judgement of sufficiently safe is therefore a very broad issue that is outside of the scope of this document, detailed guidance on this will be provided in a separate document.
As an example of the challenges of providing a definition of sufficiently safe for an AS we can consider autonomous cars, where there has been much debate and disagreement on the best approach. One approach is to judge sufficiency in comparison to a human driver. A report from the UK Law Commission  sought the views of the general public on what an acceptable comparison may be. The following three options were provided:
The results of this consultation were inconclusive, with none of these options receiving a majority response. An additional complication with all of these options is the huge range of driving capabilities that exist in human drivers which can vary enormously based on factors such as age, health, experience, level of distractions etc.
An alternative approach that has been proposed for judging what is sufficiently safe for an autonomous car is to judge the performance of the vehicle in specific scenarios, rather than assessing overall average performance. The attraction of this approach is that it should help to ensure that the risk exposure of humans to the operation of the autonomous car is fairly distributed.