## 4 Simulation Environment and Scenario Setup
### Driving Scenario Setup  
Table 3 outlines six representative driving scenarios designed to rigorously examine the robustness and adaptability of the proposed controller. These scenarios span a spectrum of real-world conditions, including regulatory cycles, urban congestion, and critical emergency responses, each varying in urgency and dynamic complexity.  
To comprehensively evaluate control performance across diverse traffic contexts, six representative driving scenarios are designed. The WLTC cycle represents standardized regulatory driving conditions involving frequent acceleration and deceleration and is used to assess overall tracking accuracy and energy efficiency across different dynamic phases. The stop-and-go scenario emulates congested urban traffic, testing the controller's ability to maintain safety and comfort under frequent low-speed oscillations. The cut-in scenario introduces a sudden intrusion from a neighboring vehicle, examining the system's emergency responsiveness and stability during abrupt spacing disruptions.  
The lead vehicle departing test evaluates how promptly and smoothly the controller transitions from car-following to free-driving mode when the preceding vehicle accelerates away. The steady cruise following case assesses control precision and energy usage under relatively calm, steady-state conditions. Finally, the emergency braking scenario imposes a safety-critical deceleration event to test the controller's capability to mitigate collision risk while ensuring comfort and compliance with physical constraints.  
\begin{table}
\begin{tabular}{l c} \hline
**Parameter** & **Value** \\ \hline Vehicle mass \(m\) (kg) & 1650 \\ Gravitational acceleration \(g\) (m/s\({}^{2}\)) & 9.81 \\ Tire rolling radius \(r\) (m) & 0.353 \\ Rolling resistance coefficient \(f\) & 0.009 \\ Frontal area \(A_{f}\) (m\({}^{2}\)) & 2.2 \\ Air drag coefficient \(C_{d}\) & 0.35 \\ Air density \(\rho\) (kg/m\({}^{3}\)) & 1.206 \\ Road grade \(\theta\) (rad) & 0 \\ Final drive ratio \(i_{0}\) & 8.47 \\ Motor inertia \(J_{m}\) (kg\(\cdot\)m\({}^{2}\)) & 0.08 \\ Final drive inertia \(J_{fd}\) (kg\(\cdot\)m\({}^{2}\)) & 0.001 \\ Single wheel inertia \(J_{w}\) (kg\(\cdot\)m\({}^{2}\)) & 1.4 \\ Equivalent body rotational inertia \(J_{eq}\) (kg\(\cdot\)m\({}^{2}\)) & 2.7 \\ Initial battery SOC & 0.8 \\ Battery capacity (Ah) & 60 \\ Battery voltage (V) & 380 \\ Rated motor power (kW) & 150 \\ Maximum motor torque (N\(\cdot\)m) & 500 \\ \hline \end{tabular}
\end{table}
Table 2: Main vehicle parameters used in the simulation environment.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Scenario** & **Duration (s)** & **Initial Speed (km/h)** & **Initial Distance (m)** \\ \hline WLTC Standard Cycle & 500 & 0 & 5 \\ Stop-and-Go & 100 & 50 & 20 \\ Lead Vehicle Departing & 100 & 80 & 30 \\ Steady Cruise Following & 100 & 40 & 50 \\ Cut-in Scenario & 100 & 60 & 50 \\ Emergency Braking & 50 & 100 & 50 \\ \hline \end{tabular}
\end{table}
Table 3: Test scenarios for ACC performance evaluation.  
This comprehensive test set enables a balanced evaluation of the controller's generalization ability, safety response, and energy-efficient performance across diverse longitudinal driving tasks.