# Measures and Methods for the Evaluation of ATO Algorithms
## 3 Approach for ATO Testing
### Layer Model  
The identified key principle _Structured Scenario Definition_ will be implemented in this approach by transferring the _6-layer model_ (6 LM) by [PERSON] et al. from the automotive domain to the railway sector. To find comprehensive documentation of the original 6 LM, the transferred model is based on, the reader is referred to [32]. A visualization of the proposed layer model for the railway sector in the context of the evaluation of ATO algorithms is presented in Figure 2.  
All layers do contain entities, which are furthermore characterized by their properties. One entity can have a variety of properties. Apart from that, entities could include a definition of relationships to another or multiple entities as defined in the 6 LM ([32]). To improve readability, the following more detailed description refers to the layers of the 6 LM using numerical phrases (one, two, etc.) and layers of the transferred model are addressed using c \begin{table}
\begin{tabular}{c c c} \hline \hline
**Jerk** & **Acceleration** & **Comfort Level** \\ \hline \(|\Delta a|\leq 1.5\) m/s\({}^{3}\) & \(|a|\leq 0.7\) m/s\({}^{2}\) & Very comfortable \\ \(1.5\) m/s\({}^{3}<|\Delta a|\leq 3\) m/s\({}^{3}\) & \(0.7\) m/s\({}^{2}<|a|\leq 1.5\) m/s\({}^{2}\) & General comfortable \\ \(3\) m/s\({}^{3}<|\Delta a|\) & \(1.5\) m/s\({}^{2}<|a|\) & Uncomfortable \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comfort levels for absolute jerk and acceleration values based on the reviewed literature. Layers one, two and three in the 6 LM are describing the static elements of a test case, thereby including spatial information of all important structures and elements which describe the static scenario components. Analogous to these layers, layers 1 and 2 of the transferred model were defined, whereby track elements, signs and signals (without the information, if it is not static) are subject to layer 1 and trackside structures like platforms, tunnels, bridges, PSD and balises are elements of layer 2. Layer three in the 6 LM describes temporal changes of layers one and two if they are consistently existing during the whole scenario. This is reasonable for road traffic because changes to the road marking, lane guidance and connected traffic rule changes (e.g., signs and traffic lights) can occur frequently. However, changes to the track position of rail lines during construction are very rare and, if present, are known in advance. The installation of fences and warning lights can serve as an example of temporal modifications on layer 2. Such changes will be subject to layer 2 for simplicity reasons, due to their limited occurrences and often long-term installation. From layer three upwards dynamic elements of a scenario are implemented which do or can contain temporal information. Their state does not necessarily need to change during the scenario but changes can occur, e.g., the sun is shining from the beginning of a scenario till the end, or clouds are slowly covering the sun and it starts to rain. Automatic train protection (ATP) is a vital function in train operation because it influences all operational phases. Layer 3, which was originally containing temporal changes to layers one and two in the 6 LM, is now reserved for the ATP system, e.g., ETCS, its components and possible interactions. When testing ATO functionalities, influences by the ATP need to be evaluated. These influences can range from providing new movement authorities (MA) to intervening when the actual speed is exceeding the ETCS emergency brake indication speed curve or maximum track speed. As a result, the train might have to brake to a full stop before continuing its drive. Layer 4 is similar to layer four in the 6 LM. [PERSON] et al. are referring to it as the \"traffic layer\" because it includes \"movable objects whose movement could evolve over time\".