## 3 Simulation Modeling  
Under the scenarios of Chinese expressways and secondary motorways and based on the traffic simulation software VISSIM, the research on the impact of SLADS on traffic efficiency and CO\({}_{2}\) emissions was carried out. The basic road sections of expressways and secondary motorways, which are both 1 km in length, were chosen to be the specific scenes. Ramps, intersections and signals were not included. There were 3 and 1 lanes in one direction on the road sections of the two types of roads separately and the width of the lanes was all set to 3.75 m. Three types of traffic conditions were set initially, which  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Acceleration Working Condition** & \multicolumn{3}{c}{**Deceleration Working Condition**} \\ \hline
**Correlation Coefficient** & **Value** & **Correlation Coefficient** & **Value** \\ \hline L0,0 & \(-\)0.67 & M0,0 & \(-\)0.67 \\ L0,1 & 0.2974 & M0,1 & 0.0166 \\ L0,2 & \(-\)0.017 & M0,2 & \(-\)0.0086 \\ L0,3 & \(-\)0.0019 & M0,3 & \(-\)0.0007 \\ L1,0 & 0.0121 & M1,0 & 0.0258 \\ L2,0 & 0.0004 & M2,0 & \(-\)0.0002 \\ L3,0 & \(-\)0.0000376 & M3,0 & \(-\)0.00000227 \\ L1,1 & 0.0283 & M1,1 & 0.0043 \\ L2,1 & \(-\)0.0009 & M2,1 & 0.00043 \\ L3,1 & 0.00000944 & M3,1 & \(-\)0.00000462 \\ L1,2 & \(-\)0.0077 & M1,2 & 0.0007 \\ L2,2 & 0.0003 & M2,2 & \(-\)0.0000561 \\ L3,2 & \(-\)0.00000373 & M3,2 & \(-\)0.00000511 \\ L1,3 & 0.0007 & M1,3 & \(-\)0.0000339 \\ L2,3 & \(-\)0.0000265 & M2,3 & \(-\)0.00000128 \\ L3,3 & \(-\)0.000000338 & M3,3 & \(-\)0.000000000761 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Parameter values of the VT-Micro model.  
were free, congested and forced condition. The traffic volume input of each condition is shown in Table 5. The lane reduction coefficients of the expressway, which was used to depict the volume distribution on different lanes, were set to 1, 0.89 and 0.78 for the first, second and third lanes [35]. Except for them, the values of road structure parameters and traffic volume above were all set according to China's 'Expressway Engineering Technical Standards' [36].  
The service level was mainly used to characterize traffic input. Within the designed service level, i.e., the designed traffic input of a road, the service level was divided into five degrees. The higher the level was, the greater the traffic input was. At each service level of the two kinds of motorways listed in Table 5, the penetration rate of ICVs with SLADS was set to 20%, 40%, 60%, 80%, and 100% respectively. In terms of driving styles, it was assumed that the proportion of the aggressive style of HVs is equal to that of Chinese aggressive styles, which is 25.9%, while the proportion of the aggressive style of ICVs with SLADS was set to 0, 20%, 40%, 60%, 80%, and 100% separately considering that the functional parameters of the SLADS can be adjusted. The changes in traffic efficiency and CO\({}_{2}\) emissions were specifically studied when HVs were gradually transitioning to ICVs with SLADS under the actual driving style ratios in China. In summary, 36 groups of simulation experiments were set for each type of road, which means that there were 72 groups of simulation experiments in total. Each group of experiments was repeated 5 times and each time was 600 s. The simulation step was set to 0.1 s.