## 1 Introduction
A significant risk was the reduced performance of the STT, which was attributed to faults in both the trucks and their trailers, as highlighted in the 2021 report [7]. This report reveals that 74% of fatal accidents involved STTs, whereas only 27% involved HGVs. The authors of this and later reports [8] suggest that transport companies frequently disregard regulations in an attempt to lower operational costs and maintain delivery schedules. There are four types of accidents recorded in AIL transport, including:  
1. STT rollover. Oversized loads must be properly balanced and secured, as loading them leads to a sudden increase in the weight of the STT and a shift in the center of gravity. This can result in the instability of the STT, increasing the risk of crushing, cracking, or other damage to the transported load due to the tipping or rollover of the STT [9; 10]. 2. Tire blowouts. Loading an STT with a super-heavy load can cause excessive strain, stretching, and blowouts of tires during AIL transport [11]. 3. Failure to break in time. Large trucks require more time to stop. When loaded, the mass of the STT increases further, extending this time even more. When a driver relies solely on their intuition, an STT with an emergency braking system can lead to collisions. 4. Jackknife accidents occur when the trailer moves at a different speed than the tractor. It results in the STT folding in a manner similar to a jackknife, with the trailer skewed at a 90-degree angle to the tractor. This can lead to rollovers or collisions with vehicles moving next to the STT (Figure 1). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Second Harmful Event** & \multicolumn{2}{c}{**2018**} & \multicolumn{2}{c}{**2019**} & \multicolumn{2}{c}{**2020**} \\ \cline{2-6} \multicolumn{1}{c}{/**Vehicle-Related Factors/**} & **Number** & **Percent** & **Number** & **Percent** & **Number** & **Percent** \\ \hline Tire blowouts or damage & 68 & 1.4\% & 60 & 1.2\% & 43 & 0.9\% \\ Brake System & 46 & 0.9\% & 55 & 1.1\% & 37 & 0.8\% \\ Turn indicators as well as marker, parking, and warning lights & 6 & 0.1\% & 4 & 0.1\% & 8 & 0.2\% \\ Power Train & 10 & 0.2\% & 8 & 0.2\% & 4 & 0.1\% \\ Headlights & 5 & 0.1\% & 6 & 0.1\% & 3 & 0.1\% \\ No Details & 3 & 0.1\% & 7 & 0.1\% & 7 & 0.1\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Large trucks in fatal crashes by vehicle age, 2018–2020 [6]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Vehicle** & \multicolumn{2}{c}{**2018**} & \multicolumn{2}{c}{**2019**} & \multicolumn{2}{c}{**2020**} \\ \cline{2-6} \multicolumn{1}{c}{**Configuration**} & **Number** & **Percent** & **Number** & **Percent** & **Number** & **Percent** \\ \hline Single-Unit, 2 Axles & 1.179 & 24.0\% & 1.172 & 23.3\% & 1.219 & 25.2\% \\ Single-Unit, 3+ Axles & 499 & 10.2\% & 517 & 10.3\% & 458 & 9.5\% \\ Truck/Trailer(s) & 237 & 4.8\% & 276 & 5.5\% & 247 & 5.1\% \\ Tractor/Semi-trailer & 2.700 & 55.0\% & 2.767 & 55.0\% & 2.566 & 53.0\% \\ Tractor/Double & 131 & 2.7\% & 124 & 2.5\% & 123 & 2.5\% \\ Tractor/Triple & 7 & 0.1\% & 5 & 0.1\% & 2 & 0.05\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Large trucks in fatal crashes by vehicle configuration, 2018–2020 [6]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**First Harmful Event** & \multicolumn{2}{c}{**2018**} & \multicolumn{2}{c}{**2019**} & \multicolumn{2}{c}{**2020**} \\ \cline{2-6} \multicolumn{1}{c}{/**Vehicle-Related Factors/**} & **Number** & **Percent** & **Number** & **Percent** & **Number** & **Percent** \\ \hline Collision with Vehicle & 3.257 & 73.0\% & 3.290 & 73.1\% & 3.183 & 71.6\% \\ Overturn (Rollover) & 187 & 4.2\% & 165 & 3.7\% & 160 & 3.6\% \\ Jackknife & 9 & 0.2\% & 12 & 0.3\% & 12 & 0.3\% \\ Cargo Equipment Loss or Shift & 2 & 0.03\% & 10 & 0.2\% & 6 & 0.1\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Large trucks in fatal crashes by vehicle-related factors, 2018–2020 [6]. Another cause is the limited space on the route of STTs.