## 4 Results and Discussion
### Traffic Capacity  
Buses are generally seen as slow-moving bottlenecks in traffic flow [21]. For the special traffic scenario under the lane multiplexing strategy, it is difficult to calculate the traffic capacity by theoretical methods because of the dynamic disturbance of the moving buses, whereas it is a better method to use CA simulation to evaluate the traffic capacity of the road section. Figure 9 presents the car traffic flow of the experimental link in each case. The maximum car traffic flow in each case can be regarded as the traffic capacity of the road section under each lane operation strategy. It is obvious that the lane operation strategy in Case C can effectively improve the traffic capacity of the road section compared with the other cases.  
When the input car flow is less than 600 veh/h, the change trend of traffic flow in the three cases is almost the same, and the car traffic flow increases steadily with the increase of the input car flow. When the input car flow reaches 600 veh/h, the traffic flow of the experimental link in Case A and Case B reaches the peak, and as the input car flow continues to increase, it remains at a stable value, which means that the traffic flow of the experimental link in Case A and Case B is saturated at this time. It can be found that the magnitude of the saturated traffic flow in Case A and Case B is almost the same, which can be ascribed to the fact that the traffic capacity of the experimental link in this simulation environment mainly depends on the traffic capacity of the downstream intersection approach. Due to the setting of the conventional intersection approach in Case B, the traffic capacity of the experimental link in Case B is not improved compared with Case A. In contrast, the saturated traffic flow in Case C is significantly increased, which indicates that the setting of IBA can effectively improve the traffic efficiency of the intersection, and then improve the traffic capacity of the road section. Table 4 summarizes the traffic capacity of the experimental link in each case at different bus volume, and it is clear that the traffic capacity of the experimental link in Case C is the highest. In addition,  
Figure 9: Car traffic flow of the experimental link in each case.  
as the bus volume increases, it is found that the traffic capacity of the experimental link in each case shows a decreasing trend, which can be ascribed to the slow-moving bottleneck effect of buses.  
Similarly, as the bus volume increases, it can also be observed that the fluctuation of the car traffic flow in Case C becomes more and more significant in the high-flow traffic environment. This can be ascribed to the frequent opening and closing of dynamic lanes, which will lead to the instability of road traffic flow. It is actually an unsatisfactory traffic state and needs to be avoided, which also confirms that when the bus volume is high, the DBL strategy is a better lane operation scheme.  
In conclusion, there is no doubt that the lane multiplexing strategy can provide bus priority while improving the traffic situation of the experimental link under certain circumstances. However, when the traffic flow of both buses and cars is high, the vehicle delays caused by the conventional intersection approach will lead to the failure of the bus priority strategy. The aforementioned limitation can be effectively compensated by adopting the proposed IBA setting method. It can maintain the continuity of vehicle running between the lane and the intersection approach in the road section, and better exert the overall operational benefits of dynamic bus lanes. Note that our work in the current paper concentrates on studying the lane operation strategies on a two-lane road section. Based on the work by [PERSON] and [PERSON] [43], the effect of a single-lane restriction is less noticeable in wider roadways, so it can be considered that the benefits of the lane multiplexing strategy would be more remarkable when there are three or more lanes in the road section.