## 3 Results
### Critical Test Scenario Selection Example Based on an Existing Vehicle
To further illustrate the filtering process and the rationale behind excluding highly similar test scenarios, a visual comparison of two nearly identical test runs is presented in Figure 4.  
These scenarios differ only slightly in two parameters--VUT speed (100 km/h vs. 90 km/h) and target speed (70 km/h vs. 60 km/h)--while all other values remain identical. During the sorting process, their CS values were 0.832 and 0.829, respectively (rounded to three decimal places), and the ED between them was 0.14. Since this ED value falls below the applied threshold of 1, the test run 'ENCAP-AD-Grading-CCR' was excluded as redundant, while test run 'ENCAP-C2C-CCRm' was retained due to its slightly more critical characteristics. Figure 4: Comparison of two highly similar test scenarios filtered based on ED threshold. Figure 3: Number of filtered test runs using calculation MD and ED. A similar conclusion was reached when analyzing various threshold values. Based on these findings, we believe the developed methodology is well-suited for achieving the stated objectives. To further examine the applicability of the methodology presented above, we conducted evaluations on two additional systems: a purely Level 3 highway diving system and a fully Automated Valet Parking System (AVPS). The results obtained from these evaluations, along with those related to the previously discussed vehicle, are summarized in Table 3 and illustrated in Figure 5. Based on the results, it can be concluded that the proposed method enables the selection of relevant scenarios effectively, while the proportion of irrelevant scenarios remained below 20% even in the worst-case scenario. Proof of Concept: Comparing the Result of the Selection with Existing Vehicle-Specific Test Scenario Catalogues from Previous Projects  
We also utilized our developed method to review previously completed projects of a TIC company to determine which scenarios should have been performed based on the filtering and compare the results with the test cases previously used. For this examination, we selected three past projects: two low-speed autonomous people mover vehicles with different capabilities and one automated highway driver function passenger car. The scenarios used in the projects were mostly modified scenarios, although they often relied on the basic test runs found in the database. Therefore, we first identified which scenarios each one was based on or which test run group they best fit into. As a result, multiple test runs from the database could be assigned to certain previous test cases. This is significant because if we identify previous test plans' individual runs with only one case, it is possible that during filtering, we might exclude the exact run to which the previous  
Figure 5: Number of filtered test runs with irrelevant runs using ED for three different vehicles. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Vehicle**} & \multicolumn{4}{c}{**Number of Test Runs**} \\ \cline{2-5}  & **Initial** & **Selected Based on WCS** & **Filtered Using Euclidean Distance (ED)** & **That Are** \\  & & & **Irrelevant** \\ \hline L3 highway driving function with AVPS & 1052 & 390 & 76 & 13 \\ \hline L3 highway driving function & 1052 & 221 & 38 & 4 \\ \hline AVPS & 1052 & 136 & 56 & 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Number of initial, selected, filtered-out and irrelevant scenarios for three vehicles. test case was assigned, even though this run might differ from its surroundings only in a parameter not relevant from the perspective of the previous test cases. In all three cases, we filtered using the threshold value of 1 described in Section 2.4. Based on this, we obtained the following results introduced in Table 4 supported by the illustration in Figure 6. In all three cases, the filtering allowed for us to identify several test runs that were not previously used but, upon expert review, would be relevant for testing. In all three cases, the number of not entirely relevant cases was not more than 20%.