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2025, Volume 43,  Issue 1

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2025, 43(1): .
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A Review of the Ethical Dilemmas of Driverless Vehicles
LI Haijian, YANG Silu, LI Yuxuan, ZHAO Xiaohua, CHEN Yan
2025, 43(1): 1-14. doi: 10.3963/j.jssn.1674-4861.2025.01.001
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With the rapid advancement of autonomous driving technology, it has demonstrated tremendous potential in enhancing traffic efficiency and safety. However, the ethical issues it raises are becoming increasingly prominent, gradually emerging as a significant constraint to its widespread adoption. This paper aims to explore the core ethical dilemmas in the development of autonomous vehicles from the perspectives of moral philosophy and institutional governance. It focuses on three major areas: algorithmic ethics, social ethics, and legal regulation, covering key topics such as moral decision-making based on utilitarianism and deontology, mechanisms for attributing accident responsibility, and global and domestic legal responses. In terms of algorithmic ethics, utilitarian and deontological approaches, including collision algorithms and moral knobs, offer solutions for ethical conflicts. Regarding responsibility attribution, the traditional human-centered liability model is evolving into a chain-based framework encompassing all stakeholders engaged in designing, producing, and operating autonomous vehicles. As for legal regulation, current legal frameworks suffer from both applicability limitations and regulatory gaps, necessitating the construction of a legal framework that aligns with technological advancements. Future research may further deepen interdisciplinary collaboration and propose more practical solutions in areas such as ethical modeling, responsibility delineation, and institutional design, providing robust ethical support for the safe and sustainable deployment of autonomous vehicles at various levels of automation.
Research Hotspots and Development Trends of Container Multimodal Transport in China
MA Yuhan, YANG Peijie, XUE Jie, ZHENG Yuan, YANG Hao, HU Hao
2025, 43(1): 15-30. doi: 10.3963/j.jssn.1674-4861.2025.01.002
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Amid accelerating globalization of international trade, container multimodal transport has emerged as the dominant mode of international cargo movement. Rising market diversification and technological innovations now drive transformative opportunities for container multimodal transport in China. To systematically summarize existing research, 475 Chinese and English articles (from 1st January 2000 to 10th July 2024) are retrieved from the China National Knowledge Infrastructure (CNKI) core database. Using CiteSpace visualization and literature synthesis, publication patterns, research status, key themes, and development trends are evaluated in China's container multimodal transport research. Key findings reveal four research domains: novel container designs, path optimization algorithms, green logistics systems, and digital platforms development. Critical challenges persist, including fragmented automation coverage, limited smart technology adoption, and inadequate algorithm validation in complex operational scenarios. Additional constraints involve underdeveloped green energy integration, incomplete carbon taxation frameworks, and cybersecurity risks in data-sharing platforms. Emerging trends highlight multidimensional innovation focusing on: AI-driven dynamic response systems for autonomous decision-making, adaptive algorithms for multi-scenario process optimization, blockchain-enabled smart contract solutions, and synergistic green energy-grid integration strategies, etc.
Effect of Driving System's Suspension Structure on Dynamics Performances of Inner Axlebox Bogie
SHE Liyun, WANG Jiaxin, LIU Yuqing, CHEN Zaigang
2025, 43(1): 31-41. doi: 10.3963/j.jssn.1674-4861.2025.01.003
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To optimize driving system's suspension structure of the inner axlebox bogie and improve service safety and reliability of the railway vehicles, a dynamics model of the inner axlebox vehicle considering driving and transmission system was established using the theories of gear dynamics and vehicle system dynamics and the multibody dynamics software SIMPACK. On the basis of the current driving system's suspension form of the bogie, three different suspension structures were proposed in this study. The proportion of traction motor mass allocated to primary unsprung and sprung under different driving system's suspension structures is analyzed. In addition, with the consideration of the internal and external excitation such as gear meshing and track random irregularity, and different driving system's suspension structures, this study investigates the dynamics characteristics such as the vibration responses of key components like traction motor, displacements of the coupling, dynamics forces at suspension points of driving system at different speeds, which revealed the effect of different driving system's suspension structures on dynamics performances of the inner axlebox bogie. The results show that the connecting rubber nodes between the gearbox and motor can limit their relative displacement and effectively protect the coupling. However, it also increases the transmission path of vibration from the wheel-rail surface to frame and driving system, leading to a significant increase in vibration levels of traction motor, frame, and other key components. In addition, reducing the number of rubber nodes between the gearbox and motor can decrease the mass of driving system allocated to the primary unsprung and the gearbox-axle joint vertical force. However, it would increase the vertical force on the motor suspension point and the gearbox rod joint. These results can provide a reference for the design of driving system's suspension structure of the inner axlebox power bogie.
Driving Collision Risk Modeling with Trajectory Prediction of Obstacle Vehicles
YANG Houxin, LU Liping, QIN Heng, YANG Ao, CHU Duanfeng
2025, 43(1): 42-51. doi: 10.3963/j.jssn.1674-4861.2025.01.004
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In order to address critical challenges in intelligent driving systems, including insufficient dynamic interaction modeling, limited accuracy in multimodal trajectory prediction, and over-reliance on single physical metrics for collision risk quantification. A proactive collision risk assessment framework is proposed by integrating probabilistic quantification with multimodal trajectory prediction. For trajectory prediction, a hierarchical graph attention network is developed to capture dynamic environmental features through adaptive fusion of high-definition maps, lane geometries, and vehicle motion history. A sliding window-optimized decoder is introduced within the conventional two-stage prediction architecture to refine trajectory outputs. For risk assessment, a probabilistic collision quantification method is designed to calculate collision likelihood between ego and surrounding vehicles based on predicted trajectories. Results on the Argoverse dataset demonstrate state-of-the-art performance with minimum final displacement error (=0.785), average displacement error (=1.157), and miss rate (=0.126), achieving 1% and 15.1% error reduction in endpoint prediction compared to HiVT and LaneGCN respectively. simulation of urban mobility, SUMO simulations reveal 5% deviation between predicted and actual risks, with risk fluctuation amplitude reduced by 33.3% and 18.75% against time to collision (TTC) and dynamic safety index (DSI) methods. The proposed model shows enhanced stability in continuous driving scenarios (risk fluctuation=0.3) and demonstrates superior accuracy in forecasting potential collision risks through systematic integration of trajectory prediction and probabilistic analysis. These findings validate the framework's effectiveness in proactive safety warning for intelligent vehicles.
SMOTE-LSTM Vehicle Accident Detection Method for Imbalanced Data
WANG Tianshuo, GAO Jingbo, TONG Shengjun, LI Zhenglong, ZHAO Xiaohua
2025, 43(1): 52-60. doi: 10.3963/j.jssn.1674-4861.2025.01.005
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In vehicle accident detection, the imbalance between the small number of accident vehicles and the large number of normal vehicles can lead to difficulties in accurately identifying accident vehicles, increasing the risk of misclassifying them as normal vehicles. Therefore, a vehicle accident detection algorithm based on SMOTE-LSTM is proposed. To address the data imbalance between accident and normal samples, the synthetic minority over-sampling technique (SMOTE) is employed to randomly insert samples between accident data points, increasing their quantity and achieving data balance between the two categories. Furthermore, when oversampling accident data, the optimal number of neighbors is selected by comparing the detection accuracy under different neighbor counts to improve the recognition rate of accident samples while minimizing noise interference. On this basis, long short-term memory (LSTM) networks are employed to accurately capture the temporal features of data when vehicle accidents occur. Additionally, a Dropout layer is introduced to reduce overfitting and enhance the model's generalization ability, ensuring accurate accident detection. To minimize the misclassification of accident vehicles as normal, class weights are incorporated into the loss function, adjusting the weights to make the model more focused on accident sample detection. Finally, six groups of comparative experiments were conducted on a collected vehicle driving state time-series dataset. The first three groups did not use the SMOTE-LSTM-based algorithm, performing vehicle accident detection under balanced, mildly imbalanced, and moderately imbalanced conditions by increasing the number of normal samples. The latter three groups employ the SMOTE-LSTM-based algorithm to address mild, moderate, and severely imbalanced conditions. Experimental results show that, with the proposed method, the values of Precision, Recall, F1-score, G-mean, and AUC are significantly improved. Specifically, under mildly class imbalance, these five evaluation metrics increase by 56.2%, 2.5%, 38.7%, 5.8%, and 5.4%, respectively. Under moderate class imbalance, the improvements are 75%, 14.1%, 59%, 8.2%, and 7.8%. The results demonstrate that the proposed algorithm effectively addresses the class imbalance issue in vehicle accident detection, significantly enhancing all evaluation metrics. Particularly in mildly and moderately imbalanced scenarios, the algorithm effectively enhances the recognition ability of the minority class, exhibiting strong robustness and better classification performance.
Analysis of Influencing Factors for Nighttime Pedestrian-vehicle Crash Injury Severity Considering Temporal Instability
TANG Yujie, JIAO Pengpeng, WANG Jianyu, LI Rujian
2025, 43(1): 61-73. doi: 10.3963/j.jssn.1674-4861.2025.01.006
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Nighttime pedestrian-vehicle crashes exhibit significantly higher injury severity than daytime crashes due to visibility limitations and other factors. To accurately identify influencing factors, this study develops a hybrid model integrating a random parameters Logit model with heterogeneity in means and variances and a random forest (RF) algorithm based on SHapley Additive exPlanation (SHAP), i.e. RF-SHAP, using crash data from 2017 to 2022. The log-likelihood ratio test confirms temporal instability in the dataset, necessitating separate models for 2017—2019, 2020, 2021, and 2022 with calculated average marginal effects for significant variables. Results demonstrate that random effects exist for drinking pedestrians (2017—2019), ambulance required (2020), local street crashes (2021), and 48—56 km/h speed limits (2022), with their mean/variance influenced by traffic control and road classification. Drinking pedestrians, pedestrians aged over 45 to 60 years, driver injuries, vehicle types (pickup trucks and trucks), divided roadways, speed limits (32—40, 48—56, 64—72 km/h), weekends, and winter conditions have begun to exhibit statistically significant effects on nighttime pedestrian-vehicle crashes in recent years. In addition, the RF-SHAP algorithm quantifies heterogeneous contributions of all sub-variables within four random parameters to crash severity. Policy implications highlight three priorities: addressing pedestrian drinking behavior, enhancing nighttime crash prevention on expressways and arterial routes, and establishing appropriate speed limits while avoiding excessively high or low values.
Multi-objective Route Optimization of Wind-assisted Ships Considering Sail Angle-of-attach Control
ZHANG Jinfeng, QIAO Fuqi, MA Weihao, ZHANG Yueqi, XIONG Maolin, WANG Yuchuan
2025, 43(1): 74-84. doi: 10.3963/j.jssn.1674-4861.2025.01.007
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To address the challenges in the route optimization of wind-assisted ships, namely insufficient quantification of wind energy utilization efficiency, limited accuracy in fuel consumption prediction, and lack of multi-objective coordinated optimization mechanism, this study proposes a multi-objective route optimization method integrating dynamic sail control with hybrid propulsion prediction. A dynamic sail control strategy model based on aerodynamic characteristics is developed to achieve spatial vector analysis of auxiliary thrust from sails. This model overcomes the limitations of conventional static angle-of-attack configurations by enabling real-time dynamic adjustment of sail parameters, thereby maintaining a high level of wind energy conversion efficiency. To resolve the dual constraints of poor environmental adaptability in traditional physical models and weak physical interpretability in data-driven approaches, a physics-constrained hierarchical artificial neural network architecture is constructed. This architecture establishes feature space bases using ship kinematic equations and employs attention-guided neural networks for residual learning. The proposed method preserves the underlying physical principles of energy consumption while enabling bidirectional coupling between data features and fluid dynamics equations. Validation on North Atlantic routes demonstrates that the proposed method reduces the mean absolute percentage error (MAPE) of fuel consumption prediction by 21.9% compared to purely physical models, while offering significantly enhanced inter-pretability over purely data-driven methods. Furthermore, a multi-objective optimization model incorporating both time costs and fuel consumption is established. A coordinated optimization algorithm combining non-dominated sorting genetic algorithm (NSGA-Ⅱ) and technique for order preference by similarity to ideal solution (TOPSIS) is developed, which improves the convergence rates of the non-dominated solution sets compared to standard algorithms. An empirical study conducted on the wind-assisted vessel"NEW ADEN"demonstrates that, during typical voyages in the North Atlantic, the effective operational efficiency of the sail is improved. Compared with the traditional recommended routes, the optimized route reduces voyage time by approximately 5%, fuel consumption costs and fixed costs by 9.1% and 4.95%, respectively, and total operational costs by over 7.2%. This optimization improves the economic benefits of wind-assisted ships while effectively reducing environmental pollution.
EEMD-PE-LSTM Based Traffic State Prediction Method for Freeway Section
ZHANG Kairui, LU You, LYU Nengchao
2025, 43(1): 85-96. doi: 10.3963/j.jssn.1674-4861.2025.01.008
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The rapid development of the highway network and the diversification of traffic demand have made traffic congestion, road carrying capacity bottlenecks, road design optimization and other issues more and more prominent. This seriously restricts the travelling experience of travelers and the service effectiveness of traffic management departments. To accurately quantify the gain of traffic conditions and weather conditions on the prediction performance of traffic flow parameters, we a combined prediction model of traffic flow parameters of highway sections construct based on the ensemble empirical modal decomposition (EEMD), permutation entropy (PE) and long short-term memory (LSTM). The study applies the EEMD algorithm to decompose the average travelling speed sequence, screens and integrates the decomposed components through the PE algorithm and proposes to perform spatio-temporal matching and feature grouping of the traffic and weather data to identify the most influential factors and their interaction modes; combined with the sliding time window strategy, the input configurations are dynamically adjusted. With the LSTM network as the core, the optimal history sequence length and feature combination are determined by iterative optimizations, and then the optimal value of the average driving speed of the target road section is obtained. At the same time, the regional characteristic-oriented traffic state determination mechanism is proposed, i.e., the 85% quartile of the average driving speed of the road section is adopted as the normal speed benchmark. Taking a highway in Hubei Province as a case study, the empirical results show that: in terms of prediction accuracy, compared with a single LSTM model, the average absolute error of the combined prediction model is significantly reduced by 73.4%; in terms of computational efficiency, it is improved by 67% compared with the EEMD-LSTM model. Especially when the length of the sliding time window is 40 min, the combined model maintains the lowest prediction error under various types of travelling scenarios and diversified feature inputs, showing good stability and robustness. In addition, the model incorporating traffic conditions reduces the prediction error range by about 60% compared to the model relying only on historical speed sequences, highlighting the key role of traffic factors in speed prediction. This study can provide scientific management decision support for traffic management departments during peak traffic periods, special events, and traffic accident emergencies.
Intelligent Segmentation Method of Inland Waterway for Energy Efficiency Optimization
ZHANG Hanyu, YIN Qinzhi, JIN Liangzhen, QIAN Weiwen, ZHANG Wenqiang, QIN Letian
2025, 43(1): 97-106. doi: 10.3963/j.jssn.1674-4861.2025.01.009
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The automatic scientific segmentation of inland waterways is significant to enhancing the accuracy of ship energy efficiency models. To address the problem of low accuracy in fuel consumption and speed prediction models built based on conventional waterway segmentation for energy efficiency optimization, an intelligent segmentation method of inland waterways aimed at optimizing energy efficiency is studied. The method incorporates the influence of navigational environmental parameters on ship energy performance into the clustering process by normalizing the data and calculating correlation coefficients between environmental parameters and energy efficiency indicators. The K-means clustering algorithm is employed to segment the entire route into multiple sections. For each segment, Random Forest algorithm is used to establish models for fuel consumption and ship speed prediction. The optimal number of clusters is determined by minimizing the overall mean absolute percentage error (MAPE) of the energy efficiency models. A case study involving an inland bulk carrier is conducted to demonstrate the application and validate the effectiveness of the proposed method, along with an analysis of the influence of data volume on the model accuracy. The results show that optimizing the number of clusters significantly improves model accuracy: in the firstly voyage, the comprehensive MAPE of the energy efficiency model is reduced from 3.53% to 3.32%. Increasing the volume of energy-related data used in model construction further enhances the performance: when the dataset expanded from one voyage to five, the comprehensive MAPE decreased from 3.32% to 1.65%. The optimal number of clusters varies with different datasets, and selecting an optimal number of clusters based on multi-voyage data leads to the optimal waterway segmentation. Compared to the conventional segmentation method, the proposed approach reduced the comprehensive MAPE of energy efficiency model by 0.54%, validating the effectiveness of the method in improving the prediction accuracy of ship energy efficiency model.
A Human Machine Function Allocation Model Based on Queue Scheduling Algorithm in the Cockpit of a Civil Aircraf
REN Boxi, SUN Youchao, LIU Weicheng, ZENG Zhe, ZENG Yining
2025, 43(1): 107-119. doi: 10.3963/j.jssn.1674-4861.2025.01.010
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The high complexity of the aircraft cockpit human-machine system (ACHMS) has resulted in increasingly heavy information flow loads for pilots. To address this challenge, a human-machine function allocation model is proposed based on queue scheduling algorithms. The operational complexity of flight procedures and pilot resource requirements during human-machine interactions are quantitatively evaluated using entropy analysis. A spatiotemporal dynamic factor-integrated metric is proposed to measure pilot information flow load intensity, serving dual purposes as directed edge weights in information interaction networks and scheduling criteria. These networks are subsequently constructed to visually represent information transmission processes and coupling relationships between pilots and cockpit interfaces. Building on the mapping relationship between ACHMS and computer operating systems, the serial scheduling mechanism of the weighted round robin (WRR) algorithm is extended. A queue-weight-based cognitive resource differential allocation and information flow queuing scheduling mechanism is established, while a human-machine function allocation strategy for cockpits is proposed based on the improved WRR algorithm. The Boeing 737 takeoff procedure serves as a validation case, with information flows systematically extracted throughout operational phases. A human-machine coupled information interaction network is constructed for takeoff procedures, with the enhanced WRR algorithm deployed for dynamic scheduling and function allocation triggering. Post-allocation analysis reveals significant improvements: pilot node closeness centrality improves by 4.82 times, betweenness centrality rises by 0.47%, and network robustness enhances 4.24 times. Maximum reductions of 86.8% in pilot load intensity and 93.5% in information coupling degree are achieved. The case verified the effectiveness of the proposed human-machine function allocation model in reducing the pilot information flow load at critical moments, thereby improve flight safety.
A Novel Ship Driver Behavior Recognition Approach Based on Improved TSM
CHEN Chen, WEI Yuenan, MA Feng, HU Songtao, WANG Tengfei
2025, 43(1): 120-129. doi: 10.3963/j.jssn.1674-4861.2025.01.011
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In maritime transportation, irregular operations by crew onboard represent a significant factor causing maritime accidents. The design of a real-time detection method for monitoring ship driver behavior holds substantial importance. Compared to automobilism driving and security surveillance, the ship's bridge environment is more complex, posing challenges such as the inability to simultaneously monitor multiple crew members, inefficiency and lower accuracy rates. To solve this problem, a two-step multi-person behavior recognition approach combining multi-target tracking and behavior recognition is proposed. Firstly, a multi-target tracker uses the YoloV7 and ByteTracker to generate continuous feature maps of crew. Based on the temporal shift module (TSM) algorithm for single-target behavior recognition, this approach utilizes techniques such as oversampling and cross-frame stitching to process continuous feature maps. Meanwhile, it leverages EfficientNet-B3 alongside the co-ordinate attention (CA) module to produce highly accurate recognition outcomes. The research establishes a ship's bridge behavior dataset "SC-Action", with data from different ship's bridge surveillance videos, including 2,000 behavior samples of both regular and irregular behaviors. Transfer learning and ablation experiments conducted on this dataset demonstrate that the proposed method achieves real-time behavior recognition of three crew at 24 frames per second, with both recognition speed and accuracy superior to mainstream algorithms. In tests targeting single-person behavior recognition, the method's accuracy improved by 1.3% compared to the baseline TSM model after applying the image enhancement module. Incorporating attention mechanism, the accuracy further increased by 1.78%, reaching 82.1%, with only a 0.1% increase in computational load. During multi-target testing, the method also surpasses leading approaches such as SlowFast in practical inference speed and performance, affirming its efficacy.
A Study on Underground Garage Traffic Simulation and Optimization of Flow Lines
HUANG Hanfeng, WANG Ning, XIE Zhengqing, WANG Ziyu, GUO Yuanwei, ZHENG Liang
2025, 43(1): 130-140. doi: 10.3963/j.jssn.1674-4861.2025.01.012
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Large-scale multi-level underground garages often experience high traffic volumes and complex traffic patterns. imposing high demands on the design and optimization of internal flowlines. To improve vehicle circulation efficiency and reduce exit delays, we propose a flowline optimization method based on traffic simulation. The road network of the garage is abstracted into an origin-destination (OD) model, with parking spaces and exits designated as origins and destinations, respectively. Time-dependent OD demand matrices are constructed and implemented within a dynamic system optimal (DSO) traffic assignment framework to simulate vehicle flow under different flowline configurations. Flowline design is evaluated based on dynamic traffic loading. Priority is given to organizing inter-level connections, particularly the directional use of ramps. Traffic conflict points near exits are reduced following the principle of minimizing interference. Road segments meeting criteria for two-way traffic are reconfigured to support bidirectional flow, enhancing overall network capacity. A case study was conducted on a two-level underground garage in a Beijing residential complex. A microscopic traffic simulation platform is developed using Simulation of Urban Mobility (SUMO), incorporating time-varying stochastic origin-destination demands generated from empirical data. Simulation results show that the proposed method significantly reduces total travel time, exit queue lengths, and congestion in critical sections. The robustness of the optimized flowline scheme is also validated under emergency conditions, including sudden changes in exit availability and unexpected increases in outbound demand. The results confirm that the proposed approach improves traffic efficiency and system resilience within underground garages.
A Free Lane-changing Decision Model Considering the Driving Style and the Interaction with Peripheral Vehicles
LONG Xueqin, MAO Jianxu, ZHAI Manrong, WANG Yuanze
2025, 43(1): 141-151. doi: 10.3963/j.jssn.1674-4861.2025.01.013
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The interactions between lane-changing vehicle and peripheral vehicles will influence the lane-changing decision behavior. In response to this, a lane-changing decision model that integrates driving styles and interactions is developed based on the lane-changing utility. Utilizing the extreme gradient boosting (XGBoost) algorithm and the density-based spatial clustering of applications with noise (DBSCAN) clustering method, drivers' short-term driving styles are categorized into conservative, typical, and aggressive types. Based on traffic conflicts of trajectories, the spatiotemporal overlap points between vehicles are determined to classify interactions. A utility quantification model is constructed across three dimensions: speed enhancement, spatial safety, and temporal safety. The weights of three sub-utilities are calculated based on MIC, then a total utility model for lane-changing decision is established. Using historical data, the total utilities of lane-changing drivers are computed in comparison to that of lane-keeping drivers, resulting in the identification of lane-changing utility thresholds. Thereby rules for lane-changing decision are formulated. The result of model's accuracy indicates that the model considering interactions significantly outperforms the model that does not, underscoring the importance of interactions in lane-changing decision. Predictions of lane-changing behavior are conducted using the radial basis function (RBF) model and XGBoost model. For conservative, typical, and aggressive drivers, accuracies of the RBF method are 0.885, 0.820, and 0.813, while the XGBoost method achieves accuracies of 0.954, 0.902, and 0.900. AI models demonstrate high predictive accuracies for lane-changing decision across all driver types. However, the predictive accuracies for the typical and aggressive drivers are lower than that of the decision model proposed in this paper (0.921 and 0.923, respectively). Additionally, non-parametric statistical tests of lane-changing utilities further validate the rationality of the model.
Analysis of the Autonomous Truck Platoon's Fuel Consumption Considering Morphological Parameters
ZHANG Xi, SONG Mingtao, HUANG Yanni, CHEN Feng
2025, 43(1): 152-160. doi: 10.3963/j.jssn.1674-4861.2025.01.014
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Air drag and fuel consumption of an autonomous truck platoon are critically influenced by its morphological parameters: longitudinal interval, lateral offset, lateral distribution mode, and number of vehicles. A comprehensive analysis of morphological parameters' impact on truck platoon fuel consumption can facilitate the rational formulation of truck platoon, optimize fuel-saving rates, and provide data for further evaluation of economic benefits. Based on the driving data, 343 two-truck platoons and 2 401 three-truck platoons with different morphological parameters are proposed. Using a three-dimensional unstructured grid modeling method, models of all these truck platoons have been developed. Air drag coefficients of all platoons are calculated by computational fluid dynamics simulations. With these air drag coefficients and a method for calculating fuel consumption, fuel consumption estimation of all platoons has been analyzed using Monte Carlo simulation. The results show that smaller longitudinal intervals and lateral offsets are more conducive to reducing the fuel consumption of a platoon, and a three-truck platoon exhibit superior fuel-saving performance compared to a two-truck platoon. For a two-truck platoon, air drag coefficients of its leader truck and its tail truck are 87.43%~100.6% and 58.0%~76.30% of that of a single truck respectively. For a three-truck platoon, the air drag coefficients of the leader truck, the middle truck and the tail truck are 84.19%~100.9%, 45.65%~81.19% and 45.24%~77.20% of that of a single truck respectively. For a dynamic truck platoon, adverse effect caused by lateral offset has been eliminated by the proposed lateral distribution mode. While the longitudinal interval equals six meters and lateral offset distributes within 90 cm with a normal distribution, average fuel saving rates of a two-truck platoon and a three-truck platoon are 10.71% and 15.65%, respectively.
Transfer Penalty Measurement of Intercity Rail Transit Hub Based on Nest Logit model
JIANG Yao, ZHAO Shengchuan, WANG Xinyue, XIA Guozhi, PAN Xiaofeng, ZHANG Hongyun
2025, 43(1): 161-168. doi: 10.3963/j.jssn.1674-4861.2025.01.015
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In the context of transit-oriented development (TOD), assessing the transfer convenience of travelers at rail transit hubs serves as a fundamental basis for optimizing transfer organization and design. However, existing domestic research lacks quantitative evaluations of intercity transfer penalty and empirical studies on the differences in transfer penalty among different traveler groups. To address this gap, this study constructs a nested Logit (NL) model with a two-tier structure (feeder travel and trunk-line travel) to characterize travelers' intercity travel mode choices. The trunk-line travel modes considered include private cars, high-speed rail, and long-distance buses, while the feeder travel modes encompass walking/bicycling, private cars/taxis/ride-hailing services, and public buses/urban rail transit. To calibrate the model parameters, revealed preference and stated preference surveys were conducted to collect intercity travel mode choice data from residents. Based on the model results, key factors influencing travel mode selection were identified, a quantitative measurement method for transfer penalty was developed, and differences in transfer impedance across different demographic groups were analyzed. The main findings of this study are as follows: ①Intercity travel mode choices are significantly influenced by socioeconomic attributes and travel mode characteristics. Among the socioeconomic attributes, the most significant factors include education level (t= 3.492), occupation (t=3.422), and private car ownership (t=-5.722). Regarding travel characteristics, the most influential factors include travel time (t=-4.745) and travel cost (t=-5.935). ②The estimated value of time for different travel stages is as follows: out-of-vehicle time 56.6 CNY/h, in-vehicle time 55.0 CNY/h, and delay time 58.0 CNY/h. The transfer penalty values, based on equivalent cost, equivalent in-vehicle time, and equivalent out-of-vehicle time, are 25.4 CNY per transfer, 26.9 minutes per transfer, and 27.6 minutes per transfer, respectively. ③There is significant heterogeneity in transfer penalty among different education, occupation, and income groups. Specifically, the transfer penalty for the postgraduate group is approximately 1.3 times that of the undergraduate group; the public sector employees exhibit transfer penalty approximately three times higher than that of students; and the high-income group (>10 000 CNY/month) has a transfer penalty 3.7 times higher than the low-income group (2 000—5 000 CNY/month). These findings provide theoretical insights and practical guidance for evaluating transfer efficiency at intercity rail transit hubs and optimizing transfer organization and planning.
Traffic Oscillation Absorption Strategy of Urban Expressway Based on WT-WOA
ZHAO Hongliang, ZHANG Zhaolei, YI Kefu, WU Wei, GUO Jing
2025, 43(1): 169-180. doi: 10.3963/j.jssn.1674-4861.2025.01.016
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Traffic oscillations are primary causes of traffic accidents, delays, and increased energy consumption at bottlenecks of urban road networks. Mitigating oscillations can significantly improve traffic efficiency and safety. A wavelet transform-based time-frequency analysis method is used to accurately capture the cycle of traffic oscillations. Additionally, an adaptive wavelet parameter calibration method is developed based on the whale optimization algorithm (WOA). A fitness function is set up based on the absolute error in identifying the start and end times of traffic shockwaves. In further, a global search mechanism is introduced to overcome the issue of local optima, dynamically optimizing the scale and translation coefficients of the wavelet transform. This approach addresses the common problem of wavelet transforms getting trapped in local optima, and the inaccuracies or misjudgments caused by fluctuations in the discriminative parameters around threshold values in traditional traffic oscillations identification methods. Based on this, a multi-objective collaborative traffic wave absorption control framework integrating energy consumption and driving safety is proposed. A multi-objective optimization function is then investigated incorporating fuel consumption rate and traffic safety indicators. A speed-guided vehicle access control mechanism is designed with dynamic speed regulation implemented upstream of the bottleneck area. By optimizing the speed of specific vehicles, the number of vehicles entering the bottleneck is reduced, accelerating the dissipation of traffic oscillations and suppressing energy loss and safety risks caused by frequent acceleration and deceleration. The results indicate that collision duration and overall collision time decreased by 73.86% and 61.07% respectively, while fuel consumption was reduced by 16.15%, after implementing the traffic wave absorption method in the bottleneck area. The energy consumption and safety risks decrease as the penetration rate increases by analysis of the impact of changes in the penetration rate of connected and autonomous vehicles on the control method. When the penetration rate reaches 0.3 or higher, the control method becomes significantly more effective, with notable reductions in both energy consumption and safety risks.