# Optimization of Cellular Automata Model for Moving Bottlenecks in Urban Roads
## 4 Conclusions  
This paper presents a two-lane cellular automaton model suitable for simulating urban road traffic that includes intersections, based on the NaSch model. The model comprehensively considers multiple key factors, such as the vehicle safety distance, speed differences between adjacent vehicles, acceleration and deceleration performance of different vehicle types, and driver reaction time, enabling it to more realistically reproduce the complex characteristics of mixed traffic flow on urban roads. Currently, research in this field is relatively scarce both domestically and internationally, and the proposal of this model makes a certain contribution to the field. Furthermore, subsequent research can be further expanded on this basis, applying the model to more complex road scenarios, such as three-lane and four-lane roads. At the same time, the vehicle update rules at intersections can also be flexibly extended based on this model, making it adaptable to the actual road  
Figure 9: Traffic flow lane-changing rate—density diagram.  
traffic conditions of different countries and cities, demonstrating strong applicability and scalability. This paper focuses on studying and analyzing the impact of the traffic flow density and the proportion of heavy-duty vehicles on the moving bottleneck effect in urban roads, from the aspects of spatial-temporal evolution diagrams, the traffic flow volume, average speeds, and lane-changing rates. The results indicate the following: (1) in the traffic flow state where heavy and small vehicles are mixed, the lane-changing behavior of vehicles is particularly evident in the spatial-temporal diagrams, and the formation process of moving bottlenecks is clearly demonstrated. The model established in this paper successfully simulates the characteristics of urban road mixed traffic flow. The simulation results are highly consistent with actual traffic conditions, achieving the expected simulation effects and possessing practical application value. (2) The higher the proportion of heavy-duty vehicles on urban roads, the stronger the moving bottleneck effect. This confirms the necessity of conducting research on the phenomena of moving bottlenecks and the traffic impact mechanisms on urban roads. (3) Based on the research in this paper, further in-depth studies will be conducted in two areas: firstly, studying the traffic flow characteristics of mixed traffic with multiple vehicle types moving at different speeds on urban roads, especially in special scenarios, such as the coexistence of autonomous and human-driven vehicles; secondly, exploring the use of platoon control methods to mitigate the moving bottleneck phenomenon on urban roads.  
Conceptualization, W.X. and L.W.; Methodology, W.X.; software, S.L. and K.L.; Validation, W.X. and Q.Z.; Formal analysis, W.X. and K.L.; Data curation, S.L. and K.L.; Writing-original draft preparation, W.X. and K.L.; Writing-review and editing, Q.Z.; Visualization, S.L.; supervision, L.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Yuxiu Innovation Project of NCUT (Project Nos. 2024 NCU-TYXXC108, 2024 NCUTYXXC218, and 2024 NCUTYXCX303).  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.  
The authors declare no conflicts of interest.