# Machine-Learning-Based Rollover Risk Prediction for Autonomous Trucks: A Dynamic Stability Analysis
## 3 Results
### Dynamic Stability Test Results for Heavy Trucks  
Figure 7 presents six driving test scenarios simulated using _TruckSim_. The simulations were conducted on five truck models, each tested at five different SSF values, and the presence or absence of an electronic stability control (ESC) system was also considered.  
Figure 8 shows the relationship between the maximum safe tilt angle and the peak LTR of Equation (4) for each truck model.  
* Circle test: In the circle test, all vehicles except for the ESC-disabled Arocs successfully maintained stability without rolling over, although some models came close to rolling but recovered their posture. The effect of ESC installation was observed in the maximum LTR difference, ranging from 0.06 to 0.35.
* DLC (double lane change) test: In the DLC test, all ESC-disabled vehicles exceeded a maximum safe tilt angle of 30-33\({}^{\circ}\), leading to rollovers in all cases. However, with ESC enabled, no vehicles rolled over. The ESC system reduced the peak LTR from Equation (4) by 0.32-0.52. Compared to the circle test, even vehicles with high stability exhibited more significant differences depending on the presence of ESC, while vehicles with lower stability showed even greater improvements with ESC activation.
* SIS (slowly increasing steer) test: Similar to the previous tests, the SIS test showed that higher maximum safe tilt angles corresponded to lower peak LTR values. Like the DLC test, ESC-disabled models with lower maximum safe tilt angles either rolled over or experienced significant wheel lift, even if a full rollover did not occur. However, fewer vehicles rolled over in the SIS test compared to the DLC test, and the average LTR values were generally lower. The ESC system reduced the maximum LTR by 0.11-0.52.
* J-turn test: In the J-turn test, most ESC-disabled models rolled over, with only a few high-tilt-angle models maintaining stability. Even among ESC-enabled models, some lower-stability vehicles still experienced rollovers. Additionally, certain high-SSF models exhibited higher maximum LTR values due to differences in ESC activation timing based on vehicle stability characteristics.
* SWD (sine with dwell) test: In the SWD test, most ESC-disabled models rolled over. Among the five models that did not roll over, some exhibited wheel lift in certain tests, and three models recorded LTR values above 0.87. In contrast, all ESC-enabled models successfully avoided rollovers, and vehicles with higher maximum safe tilt angles exhibited increased stability.
* Fishhook test: The fishhook test results were similar to the SWD test, where most ESC-disabled models experienced rollovers. Among the five models that did not roll  
Figure 7: Comparative analysis of six dynamic stability cases for heavy trucks.  
over, some experienced wheel lift, and two models recorded LTR values above 0.88. In ESC-enabled models, vehicles with a maximum safe tilt angle exceeding 30\({}^{\circ}\) generally did not roll over. However, their peak LTR values were mostly above 0.6, indicating lower stability compared to other test scenarios.