## 4 Numerical Simulations
### Experiments Design and Parameter Settings
on the current motion state of all related vehicles, while CACC_Sine is an independent control structure and is non-optimal for the following vehicle's control quantity, which only relies on its preceding vehicle. Figure 8 shows the actual and expected longitudinal distances between vehicles M and A and their preceding vehicles of two control strategies in scenario 1. In the LC-O stage, it is evident that the CACC_Sine control strategy has a better tracking control effect as compared to the proposed CLC control strategy, because it considers that the tracking-preceding vehicles of controlled vehicles doesn't change in this stage. However, for vehicle A, it is unable to provide a sufficient gap for vehicle M to cut into the lane when its preceding vehicle suddenly switches to vehicle M. Due to the consideration of preceding vehicle switching in the proposed CLC control strategy, vehicle A is far away from its expected distance in the late period of the LC-O stage to make preparation for vehicle M's merging. In the LC-T stage, as compared with the CACC_Sine control strategy, the proposed CLC control strategy has a better tracking control effect for vehicle A, while having a relatively larger tracking control error in the early LC-T stage, i.e., from 3 s to 10 s. However, it can reach the expected tracking state at about 20 s which is the same as CACC_Sine control strategy. Figures 9 and 10 show the comparison between the longitudinal accelerations and jerks for the proposed CLC control strategy and the comparative CACC_Sine control strategy. The acceleration and jerk of the proposed CLC control strategy are more continuous. However, the CACC_Sine control strategy shows sharp variations with extreme fluctuations. According to Figure 10, it is easy to observe that the longitudinal jerk of the proposed CLC control strategy fluctuates within a low range, i.e., from \(-0.8\) m/s\({}^{3}\) to \(0.4\) m/s\({}^{3}\). However, the longitudinal jerk of the CACC_Sine control strategy fluctuates more frequently and with greater amplitude, i.e., greater than \(4\) m/s\({}^{3}\), which causes a significant driving discomfort. As a result, the proposed CLC control strategy has smoother acceleration and less fluctuating jerk compared to the comparative CACC_Sine control strategy, thus ensuring driving comfort and leading to a better driving experience. Figure 8: The actual and expected longitudinal distances between vehicles M, A and their preceding vehicles in two stages of the two control strategies in scenario 1. (**a**) The proposed CLC control strategy, (**b**) CACC_Sine control strategy. Figure 9: The longitudinal accelerations of vehicles M and A of the two control strategies in scenario 1. (**a**) The proposed CLC control strategy, (**b**) CACC_Sine control strategy. Similarly, Figures 11-15 show the longitudinal positions and speeds of vehicles M, A, and B, and the longitudinal distances between vehicles M, A, and their preceding vehicles and longitudinal accelerations and jerks of vehicles M and A of two control strategies with the change of time for another typical lane change scenario. As compared with scenario 1, in scenario 2, the vehicles M and A in scenario 2 are closer longitudinally and the speed differences between vehicle M and vehicles B and A are smaller. Figures 11-13 show that when the longitudinal distance between vehicles on the target lane is unable to meet the safe lane-changing gap, the proposed CLC control strategy smoothly completes the preceding vehicle switching and actively changes the speed of vehicle A in the LC-O stage to ensure the safety of vehicle M when entering the target lane in the LC-T stage. Based on this smooth switching method, a more continuous speed profile can be obtained, which can produce a leading effect on the upstream traffic flow.