## 3 Crash Prediction Testing Methodology
### Hazard Analysis and Risk Assessment  
Hazard analysis and risk assessment is performed based on ISO 26262 and ISO/PAS 21448 guidance. The development is carried out according to ISO 26262-6, whereby the classification of the ASIL level can only take place in the context of the targeted Pre-Crash systems. Here, a distinction is made between QM and ASIL A+ classified target systems. Systems such as predictive eCall or reversible belt pre-pretensioner with a low force level can be classified as QM Pre-Crash systems. However, reversible seat belt with a high force level, which replaces the conventional pyrotechnic seat belt, is classified as ASIL B [22].  
Thus, it is not sufficient to consider only whether the Pre-Crash system is reversible or irreversible; the relevant question is if there is a risk of harm for all traffic participants and what risk factors of the systems can lead to it. The target Pre-Crash system hazard and risk should be assessed according to the five proposed risk characteristics:  
* Reversibility
* Distraction
* Fallback level
* Risk of injury by the PCS for host vehicle occupants
* Risk of injury by the PCS for opponents  
Depending on the ASIL classification of the targeted Pre-Crash system, different requirements arise for the accepted probability of system failure and thus the robustness and accuracy of the crash severity prediction function. Examples of addressed PCS and a classification of risk characteristics are shown in Table 1.  
While predictive eCall function is classified as QM, the Pre-Crash airbag activation receives ASIL D classification. Fallback level defines a secondary system, which is engaged when the primary system fails. In the case of Pre-Crash airbag activation there is no fallback level if the system is activated as a result of false positive prediction, since the airbag is already deployed. In addition, false positive Pre-Crash activation of airbag can lead to a provoked collision, which leads to injury risk not only for host, but also other traffic participants. For false negative activation, thus no Pre-Crash airbag activation, the conventional In-Crash activation of airbag as a fallback level is still possible.  
Thus, a crash prediction function developed and validated according to ASIL B meets the safety requirements for the reversible seat belt deployment with a high force level, but not for the Pre-Crash activation of the airbags or collision constellation optimization. Based on the HARA results, a functional modification of the system can be made before further development and validation steps are performed.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**PCS** & **Irreversible** & **Distracting** & \begin{tabular}{c} **Fallback** \\ **Level** \\ \end{tabular} & \begin{tabular}{c} **Risk of** \\ **Injury Host** \\ \end{tabular} & \
\begin{tabular}{c} **Risk of** \\ **Injury Oponent** \\ \end{tabular} &
\begin{tabular}{c} **ASIL** \\ **Class** \\ \end{tabular} \\ \hline Predictive & No & May & Yes & No & No & QM \\ eCall & & & & & & \\ e seat belt & No & May & Yes & No & No & QM \\ eNewsible & & & & & & \\ eseat belt & No & Yes & May & Yes & May & ASIL B \\ (high-force) & & & & & & \\ Pre-Crash & & & & & & \\ airbag & Yes & Yes & No (for FP) & Yes & May & ASIL D \\ activation & & & & & & \\ Collision & & & & & & \\ constellation optimization & Yes & Yes & No & Yes & Yes & ASIL D \\ \hline \hline \end{tabular}
\end{table}
Table 1: Examples of Pre-Crash systems and assignment of the risk characteristics.