## 5 Results and Discussion
### Comparison of Integrated Controller Actions  
To better compare the differences in strategy selection between the FM-ITC and FM-ITC-Darea algorithm frameworks, the changes in speed limit values, lane-changing coefficients, and control region lengths under two strategies are, respectively, shown in Figure 12. It can be observed that both control strategies tend to impose lower speed limits on the outer lane (Lane 1) to reduce the bottleneck caused by merging. These speed limits are often set at the minimum speed limit, indicating that under higher traffic demand conditions, the FM-ITC with a fixed control region may not be able to achieve the most effective control (i.e., the traffic speed within the speed limit area can even be lower than the speed limit value). In response to different traffic scenarios, the FM-ITC-Darea can avoid this issue by dynamically adjusting the length of the control region. It is evident that an integrated control system using a dynamic control region can adopt more lenient speed limits, thereby reducing the interference of speed limits on overall traffic. Figure 13 shows the lane transfer coefficients of the cells before the two on-ramps under the FM-ITC and FM-ITC-Darea strategies. It can be observed that before Ramp 1, both strategies tend to close the possibility of flow from the inner lanes to the outer lanes. By adjusting the flow from the outer lanes to the inner lanes, they alleviate the traffic conflicts between the outer lanes and the on-ramps. Before Ramp 2, the LCC agent in the FM-ITC-Darea strategy allows some flow from Lane 3 to Lane 2. This is because the LCC \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Control Strategy**} & \multicolumn{2}{c}{**Simulation Results**} & \multicolumn{2}{c}{**Improvement**} \\ \cline{2-5}  & **TTS (s)** & **TVT (veh)** & **TTS (\%)** & **TVT (\%)** \\ \hline No control & 1070 & 70,862 & - & - \\ SPSC-LCC & 1098 & 71,768 & \(-\)2.6 & 1.3 \\ FM-ITC & 990 & 72,493 & 7.5 & 2.3 \\ FM-ITC-Darea & 960 & 72,759 & 10.3 & 2.7 \\ \hline \end{tabular}
\end{table} 
Table 2: Comparison of traffic performance indicators for different control strategies. Figure 12: Variation of speed limit values for different integrated control strategies, where (**a**) and (**b**) correspond to FM-ITC speed limit changes at entrance ramps 1 and 2, respectively, and (**c**) and (**d**) correspond to FM-ITC-Darea speed limit changes at entrance ramps 1 and 2, respectively. agent's control range expands under dynamic control areas (see Figure 14b), preventing more severe bottlenecks in Lane 3. By observing the changes in the dynamic control range actions of the VSL (a) and LCC (b) agents in Figure 14, it can be seen that under the current demand level, the integrated control strategy often prioritizes the adjustment of vehicle transfers and control  
Figure 14: Variation of dynamic control area length for different integrated control strategies. where, (**a**) represents the variation in the control length of VSL agents at different bottlenecks, and (**b**) represents the variation in the control length of LCC agents at different bottlenecks. Figure 13: Variation of lane transfer factor for different integrated control strategies, where (**a**–**d**) denote the lane transfer coefficients of the two entrance ramp merge pre-cells under the FM-ITC strategy, and (**e**,**f**) denote the lane transfer coefficients of the two entrance ramp merge pre-cells under the FM-ITC-Darea strategy. ranges of the outer lanes. This not only alleviates the formation of traffic bottlenecks in the outer lanes but also, to some extent, avoids the VSL speed limits from affecting the overall traffic efficiency. In our experiments, both the VSL agent and the LCC agent in the integrated control strategy framework have the ability to dynamically adjust their control ranges. For the VSL agent, this ability helps avoid the failure of speed limits due to excessive congestion within a limited control range.