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Two-vehicle cooperative lane change strategy for intelligent and connected buses in the mandatory lane change process of entry and exit
Journal of Tsinghua University (Science and Technology) 2024, 64(8): 1456-1468
Published: 15 August 2024
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Objective

The process of buses entering and exiting a station often accompanies mandatory lane change, which can significantly impact traffic safety and efficiency. However, current research on lane change strategies for intelligent and connected buses relies on single-vehicle algorithms, lacking consideration for surrounding vehicles and facing challenges in handling inter-vehicle conflicts. These approaches also struggle to ensure the safety and success rate of mandatory lane change during entry and exit, and easily impact the traffic flow. To improve the performance of mandatory lane change for intelligent and connected buses during the entry and exit processes, a two-vehicle cooperative lane change strategy based on the cloud control system (CCS) is proposed, which can schedule buses and cooperating vehicles simultaneously.

Methods

This study designed a set of cooperative lane change strategies for the entry and exit processes. For the entry process, the road segment leading to the bus station was divided according to the distance to the station, and a decision-making model based on the lane change benefit criterion was established. A two-stage trajectory planning method was developed for lane change trajectories, incorporating the longitudinal adjustment and cooperative lane change stages. Optimization problems were formulated and solved in a receding horizon to obtain the optimal trajectories. A layered quadratic programming method was also employed to improve the real-time performance of the algorithm. For the exit process, to adapt to the characteristics of the exiting motion of buses, a rule-based decision-making method and pre-deceleration rule were designed. Lane change trajectories were optimized considering the characteristics of bay-style bus stations to meet the station shape and bus mobility requirements. Finally, the NGSIM dataset was used to design typical scenarios for simulation and hardware-in-the-loop experiments. The effectiveness of the proposed strategy was tested. The proposed strategy was also compared with baseline methods, i.e., the minimizing overall braking induced by lane change (MOBIL) decision model along with the fifth-order polynomial single-vehicle planning method, and the rule-based decision model along with the fifth-order polynomial single-vehicle planning method for the entry and exit processes, respectively.

Results

The simulation and hardware-in-the-loop experiments under typical scenarios demonstrate that the proposed strategy can effectively adapt to realistic vehicle speed changes, assisting buses in completing lane changes during station entry and exit. Moreover, when faced with the actual computing and communication environment of the cloud platform, the proposed strategy meets the requirements for real-time and effective calculations. The comparison with the baseline method shows that, in batch tests for station entry and exit, the lane change success rates of the proposed strategy were 87.4% and 82.4%, respectively, both higher than the baseline method's 51.9% and 20.4%, respectively. Evaluation metrics based on the following vehicle's speed, acceleration, and time to collision (TTC) also indicate that, compared with the baseline method, the proposed strategy can reduce the impact of mandatory lane change on traffic efficiency while maintaining better safety standards.

Conclusions

Using the CCS to achieve centralized decision-making and trajectory planning for scheduling buses and cooperating vehicles simultaneously, the proposed strategy can effectively handle mandatory lane change under high traffic density conditions. The proposed strategy not only improves the success rate of mandatory lane changes for buses entering and exiting stations, but also ensures lane change safety and reduces the impact on upstream traffic. The proposed strategy is also applicable in cloud platforms under realistic computing and communication environments.

Open Access Research Article Issue
Collaborative multi-lane on-ramp merging strategy for connected and automated vehicles using dynamic conflict graph
Journal of Intelligent and Connected Vehicles 2024, 7(1): 38-51
Published: 31 March 2024
Abstract PDF (2.9 MB) Collect
Downloads:99

The on-ramp merging in multi-lane highway scenarios presents challenges due to the complexity of coordinating vehicles’ merging and lane-changing behaviors, while ensuring safety and optimizing traffic flow. However, there are few studies that have addressed the merging problem of ramp vehicles and the cooperative lane-change problem of mainline vehicles within a unified framework and proposed corresponding optimization strategies. To tackle this issue, this study adopts a cyber-physical integration perspective and proposes a graph-based solution approach. First, the information of vehicle groups in the physical plane is mapped to the cyber plane, and a dynamic conflict graph is introduced in the cyber space to describe the conflict relationships among vehicle groups. Subsequently, graph decomposition and search strategies are employed to obtain the optimal solution, including the set of mainline vehicles changing lanes, passing sequences for each route, and corresponding trajectories. Finally, the proposed dynamic conflict graph-based algorithm is validated through simulations in continuous traffic with various densities, and its performance is compared with the default algorithm in SUMO. The results demonstrate the effectiveness of the proposed approach in improving vehicle safety and traffic efficiency, particularly in high traffic density scenarios, providing valuable insights for future research in multi-lane merging strategies.

Open Access Viewpoint Issue
The status, challenges, and trends: an interpretation of technology roadmap of intelligent and connected vehicles in China (2020)
Journal of Intelligent and Connected Vehicles 2022, 5(1): 1-7
Published: 07 January 2022
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Downloads:117
Purpose

The rapid development of Intelligent and Connected Vehicles (ICVs) has boomed a new round of global technological and industrial revolution in recent decades. The Technology Roadmap of Intelligent and Connected Vehicles (2020) comprehensively analyzes the technical architecture, research status and future trends of ICVs. The methodology that supports the roadmap should get studied.

Design/methodology/approach

This paper interprets the roadmap from the aspects of strategic significance, technical content and characteristics of the roadmap, and evaluates the impact of the roadmap on researchers, industries and international strategies.

Findings

The technical architecture of ICVs as the “three rows and two columns” structure is studied, the methodology that supported the roadmap is explained with a case study and the influence of key technologies with proposed development routes is analyzed.

Originality/value

This paper could help researchers understand both thoughts and methodologies behind the technology roadmap of ICVs.

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