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To promote the application of automated vehicles in large airports, in this study, we present an integrated optimization method for scheduling Unmanned follow-me cars. The scheduling process is divided into three phases: Dispatch, Guidance, and Recycle. For the Dispatch phase, we establish a vehicle assignment model, to allocate the vehicle resource equitably. For the Guidance phase, we offer an quantitative way, to measure the spacing between Unmanned follow-me car and aircraft. To optimize the efficiency of airport operation in the three phases and ensure safety, the collaborative planning model, and the conflict prediction model are established. An improved grey wolf optimization algorithm is adopted to enhance the convergence speed and generalization performance. A case study at Ezhou Huahu Airport in China demonstrates the effectiveness of the methods. The results show that the model of collaborative planning can make the balance of path selection, Unmanned follow-me car's working time, and departure sequence. The convergence speed of the improved algorithm has been increased by 18.75%. The inequity index of vehicle assignment is only 0.015731, and the spatiotemporal distribution of conflicts is influenced by the airport's surface layout. [ABSTRACT FROM AUTHOR]

Microscopic traffic flow models enable predictions of traffic operations, which allows traffic engineers to assess the efficiency and safety effects of roadway designs. Modeling vehicle trajectories inside intersections is challenging because there is an infinite number of possible paths in a two-dimensional space, and drivers can simultaneously adapt their speeds as well. To date, human driver models for simultaneous longitudinal and lateral vehicle control based on the infrastructure characteristics and interactions with other drivers inside an intersection are still lacking. The contribution of this paper is threefold. First, it proposes an integrated microscopic traffic flow model to describe human-driven vehicle maneuvers under interactions. Drivers plan their heading and acceleration in the predicted future to minimize costs representing undesirable situations. The model works with a joint optimization for an interaction cost term. The weights associated with the interaction cost reflect how selfish or altruistic drivers are. Second, the proposed model endogenously gives the order of vehicles in case of crossing paths. Third, the paper develops a clustered validation method for microscopic traffic flow models with interacting vehicles, which account for interdriver variations. Results show that the model can accurately describe vehicle passing orders of interacting maneuvers, paths, and speeds against empirical data. The model can be applied to assess various intersection designs. Funding: This work was supported by the National Natural Science Foundation of China [Grants 71971140 and 52122215] and the Natural Science Foundation of Shanghai [Grant 20ZR1439300]. [ABSTRACT FROM AUTHOR]

With the rapid development of railways in China, effective coordination of the operation of high-speed trains on existing tracks can bring significant economic benefits to railway transportation. However, high-speed trains running on existing tracks will have to cope with larger track irregularities and navigate smaller curve radii, potentially increasing their vibrations. In order to improve the quality of operation of high-speed trains on existing railways, a self-adjusting hybrid damping control (SAHDC) strategy utilizing a fuzzy controller is adopted in this study. A secondary lateral magnetorheological damper (MRD) is controlled to balance the vibration between the car body, bogie, and wheelset. The MRD behavior is described using a viscoelastic-plastic (VEP) model and nonlinear autoregressive exogenous (NARX) inverse model. A dynamical vehicle model with 50 DOFs is constructed and simulated under different existing track conditions. The results show that the SAHDC can guarantee the required ride quality of the car body, while reducing the vibration of the bogie frame and wheelsets as much as possible during travel on straight and curved tracks and suppressing derailment on turnouts. [ABSTRACT FROM AUTHOR]

Government policies that contain incentives have promoted the development of China's electric vehicle (EV) market from its inception. However, following the dramatic evolution of the EV market, the incentives impose a considerable burden on the State. It is time to consider abolishing various policy incentives. This paper uses the discrete choice experiment (DCE) model to study how consumer behaviours are influenced by the different policies. A system dynamics simulation model is constructed to simulate long-term EV development trends while considering the impacts of these policies. The simulations use the results from the DCE model to measure the sensitivity to policy changes of consumer purchase intentions (measured by consumers' willingness to purchase EVs). Finally, in relation to likely future policy trends, this study designs policy portfolio scenarios that are a strong mix, mid-mix, weak mix, or fully market-oriented with varied timing for policy implementation, and that are likely to affect the growth of China's EV market. The results of the simulation indicate that the optimal policies: (1) continue to increase government expenditure and support for the construction of charging facilities; (2) make charging more accessible and convenient; and (3) implement bans on the sale of fossil-fuelled cars. The results also show that the ideal timing for banning the sale of fossil-fuelled cars and, in parallel, cancelling current incentive policies (e.g. consumer purchase subsidies) is around 2025. These changes could reduce government expenditure and thus confer substantial financial savings, and they would effectively promote a significant increase in EV sales. Key policy insights Increasing support for the construction of charging facilities, improving the access and convenience of charging, and implementing bans on the sale of fossil-fuelled cars could increase consumer willingness to purchase EVs in China. Support for the construction of basic charging facilities should continue to increase and accelerate leading up to 2025; this would promote a significant increase in EV sales. To send clear near-term signals to the EV market – both consumers and producers, the Chinese government could usefully implement a ban on the sale of fossil-fuelled cars by around 2025 and in parallel abolish the current incentives policy for EVs. Abolishing current policy incentives (e.g. subsidies and VAT tax exemption) in the same time frame as other policies (e.g. support for charging infrastructure and a ban on fossil-fuelled cars), could lead to substantial financial savings to the government and a rapid scaling in the market for EVs. Lessons learned from China's potentially large and rapidly growing EV market will have implications for other countries in Asia and beyond. [ABSTRACT FROM AUTHOR]

The United States’ Inflation Reduction Act (IRA) introduces new eligibility requirements for existing USD 7,500 tax-credit provided to electric vehicles. The new requirements condition the credit upon North American final assembly and North American-sourced materials and components. As tensions flare between the US and China, these new local content requirements reflect the US’s effort to establish a supply chain for electric vehicles that circumvents China. The blow, however, is felt elsewhere, namely by South Korean auto makers whose electric vehicle models are no longer eligible for the significant tax-credit necessary to compete in the American market. As South Korea considers submitting a complaint to relevant international bodies, this paper dissects the IRA’s relevant provisions and analyzes the applicability of international trade law rules of the WTO and the Korea-US Free Trade Agreement to the new local content requirements of the IRA. [ABSTRACT FROM AUTHOR]

Based on the demand of vehicle emission research and control, this paper presents the development of a portable vehicle measurement system (PEMS) based on SEMTECH-DS and ELPI+, the vehicle emission tests carried out on actual roads, and the data obtained for the establishment and validation of a vehicle emission model. Based on the results of the vehicle emission test, it was found that vehicle driving conditions (speed, acceleration, vehicle specific power (VSP), etc.) had a significant impact on the pollutant emission rate. In addition, local driving cycles were generated and the frequency distribution of VSP-bin under different cycles was analyzed. Then, through the establishment of an emission rate database, calculation of emission factors and validation of the emission model, a vehicle emission model based on actual road driving conditions was developed by taking VSP as the "surrogate variables". It showed that the emission factor model established in this study could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. Through this study, it could be found that due to the great differences in traffic development modes and vehicle driving conditions in different cities in China, the emission model based on driving conditions was a better choice to carry out the research on vehicle emission in Chinese cities. Compared with directly applying international models or quoting the recommended values of relevant macroscopic guidelines, the emission factor model established in this study, using actual driving conditions, could better reflect the vehicle transient emissions on the actual road with high accuracy and local adaptability. In addition, due to the rapid development of China's urban traffic and the rapid change of driving conditions, it was of great significance to regularly update China's urban conditions to improve the accuracy of the model, no matter which model was chosen. [ABSTRACT FROM AUTHOR]

This paper introduces a new type of suspended monorail developed in China with the advantages of both German and Japanese monorails. The FE (finite element) model of the bridge is built in Ansys and coupled with the multibody dynamic model of the vehicle in the UM (Universal Machine). software. FIALA formula is used to construct the tire model. Then, the vehicle-bridge coupling system of the new type suspended monorail is set up and simulated with Park method. The result of the modal analysis and vehicle-bridge coupling simulation draw the same conclusion that the span of the stiffeners could result in the resonance of the vehicle system, which is due to the coupling of the frequencies of the natural modes of the car body and bogie with that for vehicle passing through stiffeners. Through the multibody dynamic simulation of the vehicle-bridge coupling system, the modes of the bridge at the frequencies of 5–10, 15–25 and 30–40 Hz are easily excited when the vehicle passes through the bridge. The three constraint modes and free modes of the bridge are similar in these frequency ranges. [ABSTRACT FROM AUTHOR]

China has become the global largest electric vehicle (EV) market, making the energy and climate issues of EV industry in terms of life cycle attract widespread attention. Based on the self-designed life-cycle analysis tool and up-to-date database, this study analyzes energy consumption and greenhouse gas (GHG) emissions of a typical passenger internal combustion engine vehicle (ICEV), and battery EV (BEV) and plug-in hybrid EV (PHEV) installed with different lithium-ion battery types, covering both fuel cycle and vehicle cycle. Owing to the battery installation, which shares nearly 30% of the GHG emissions in EV's vehicle cycle, the BEV and PHEV emit 13533–15445 kgCO 2 ,eq/vehicle and 11572–12186 kgCO 2 ,eq/vehicle, 65.6%–89.0% and 41.6%–49.1% higher than that of the ICEV, respectively. EV's fuel-cycle low emissions offset its surplus emissions in vehicle cycle. The EV generates 219.8–230.9 gCO 2 ,eq/km in life cycle, achieving 18.3%–22.6% of reduction compared to the ICEV. Development of non-fossil power will highlight the advantages of EVs in energy conservation and GHG emission reduction, e.g. if the proportion of coal power decreased to 10%, BEV's life-cycle GHG emissions will reduce about 70% than current level. Policies should focus on both EVs development acceleration and the low-carbon automotive and battery industry creation. • A life-cycle carbon footprint analysis model for passenger vehicles is built. • The database reflects up-to-date energy efficiency of China's automobile industry. • The vehicle-cycle GHG emissions of an EV are higher than a comparative ICEV. • The traction battery shares nearly half of a BEV's vehicle-cycle GHG emissions. • EVs' lower emissions in the fuel cycle offset their vehicle-cycle higher emissions. [ABSTRACT FROM AUTHOR]

The contact band on the wheel and rail is an intuitive representation of the wheel–rail contact relationship that affects the dynamic performance of rail vehicles. In this paper, a vehicle dynamics model and the Archard wear model are established in an integrated way using the actual parameters of a metro train. The mechanism of formation of double contact bands on the wheel and rail in a metro line in China is studied by analysing the geometric combination based on the measured data. The influence of double contact bands on the dynamic performance of the metro vehicle is investigated. To suppress the formation of double contact bands, an optimisation method for asymmetric rail profiles in small radius curves is proposed based on the Kriging Surrogate Model (KSM) and the Particle Swarm Optimisation (PSO) algorithm. Through numerical simulations, it is proved that the optimised rail profiles can improve the curving performance and effectively reduce wheel wear. The methodology proposed in this paper can provide useful information on the mitigation of severe double contact bands on wheel and rail. • Double contact bands were found on wheel and rail profiles in a metro line. • Formation mechanism is explained by geometric contact analysis and wear simulation. • Two-point contact on sharp curves induces double contact bands. • Asymmetric rail profiles optimisation is proposed to mitigate double contact bands. • Optimisation uses Kriging surrogate model and particle swarm algorithm. [ABSTRACT FROM AUTHOR]

Vehicle survival rate models have been extensively built in developed countries and China in view of the availability of vehicle scrappage data, but many developing countries do not have those data. This paper intends to develop Weibull distribution-based models of vehicle survivorship for Metro Manila, Philippines, without using the vehicle scrappage data. The proposed computation procedure can capture the dynamics of average vehicle lifespan. Light-duty passenger vehicles are classified into two main categories: car (sedan, hatchback) and utility vehicle (SUV, van, minivan, pickup, wagon, Jeepney). The results highlighted that the average lifespan of the car decreased from 23.23 years in 2007 to 15.22 years in 2016, whereas the average lifespan of the UV was constant and equal to 14.18 years. Also, the developed models were applied to project the vehicle stocks, scrapped vehicles, and vehicle sales based on two designed scenarios: historical trend and limitation of the vehicle stocks. [ABSTRACT FROM AUTHOR]

The validity of performance evaluation is determined by, and therefore greatly influenced by, the accuracy of data set. To address such imprecise and negative data problems widely spread in the real world, this paper proposes a second-order cone based robust data envelopment analysis (SOCPR-DEA) model, which is more robust to data variety. Further, this new computational tractable model is applied to analyze 13 new-energy vehicle (NEV) manufacturers from China. The findings support that the SOCPR-DEA model could well mitigate the deficiency caused by data variety, and the evidence from Chinese NEV industry shows that a focus strategy is more likely to enhance a firm's efficiency especially at its emerging stage, and the efficiency is more sensitive with production cost than other factors such as research and development, sales income, earnings per share, and predicted income. In addition, this paper also gives some industrial implications and policy suggestions based on these interesting findings. [ABSTRACT FROM AUTHOR]

The rapid development of sensing, computing, and wireless communication techniques has given rise to an increasing number and increasing availability of high-resolution data that record real-time traffic information. In this study, radio frequency identification (RFID) data collected in Nanjing (a major city in southern China) were used to estimate dynamic travel demands and develop an RFID data-based vehicle routing model that simultaneously considers individual benefits and social good. The proposed vehicle routing model also used information regarding driver origins that contribute to major congestion; therefore, the routing model can be applied to a group of targeted vehicles only, providing more adaptive, efficient, and feasible routing strategies to mitigate traffic congestion. [ABSTRACT FROM AUTHOR]

• Right-turning vehicle-pedestrian conflict assessment at intersection crosswalks. • Various behavior models are integrated to a simulation platform. • The frequency and severity of conflict can be represented by SSMs. • Large dimensions and turning angles result in undesirable safety performance. Frequent vehicle-pedestrian conflicts deserve special attention for safety assessment at intersections. This study helps verify how the simulation as an innovative approach can be utilized for right-turning vehicle-pedestrian conflict assessment at intersection crosswalks prior to implementation. Various behavior models such as vehicle turning path, turning speed, gap acceptance model and pedestrian behavior model, have been established. Through integrating the calibrated models into one simulation platform, the stochastic behavior of vehicles and pedestrians under different geometric layouts and operational conditions can be reproduced. Based on the field data collected by an unmanned aerial vehicle (UAV) at two urban intersections in Beijing, China, it was demonstrated through validation of surrogate safety measures (SSMs), i.e., Post Encroachment Time (PET) and vehicle passing speed at conflict points, that the simulation model can reasonably represent the frequency and severity of conflict occurrence at signalized crosswalks. The sensitivity analysis results indicated that large dimensions and turning angles of intersections tend to result in undesirable safety performance. [ABSTRACT FROM AUTHOR]

Highlights • To characterize vehicle emissions in a mountainous terrain in China using PEMS. • To examine the gaseous emissions of LDGVs of different Chinese emission standards. • To investigate the effects of mountainous terrain on VSP and emissions. • Current emission standards on unburned hydrocarbons are stagnant in China. • Current operating mode classification in MOVES is not adequate for mountainous roads. Abstract Light-duty gasoline vehicles (LDGVs) account for the largest portion of all in-use vehicles and a substantial amount of emissions in China. Among many contributing factors, the joint effect of driving conditions and road grade in a mountainous terrain on vehicle emissions is much less studied than on a level terrain, especially in China. This study presents a real-world investigation of gaseous pollutants (CO, NOx, and HC) and greenhouse gas (CO 2) emissions from LDGVs of different Chinese emission standards ranging from China 3 to China 5. Two driving routes representative of the characteristics of a mountainous and a level road respectively were selected, and instantaneous emissions and other relevant data were collected with the Portable Emission Measurement Systems (PEMS). The results demonstrate the statistically significant impact of road grade on the vehicle specific power (VSP) and emissions even after controlling for speed and acceleration (drive schedule) and emission control standards. An analysis of variance (ANOVA) reveals that, within each of the MOVES-defined operating modes, statistically different emissions are observed across different road grade levels. In other words, the current MOVES-defined operating modes may be inadequate for binning and modeling vehicle emissions of a mountainous terrain. When establishing an emission model for China, more careful classification of operating modes is needed by road grade and terrain type. The study also reveals the lack of improvement in the real-world HC emission control as a result of the stagnant HC emission standards particularly between China 4 and China 5. [ABSTRACT FROM AUTHOR]

Rapid motorization has made vehicles become one of the major sources of air pollution and poses substantial risk to human health. Accurate estimation of spatiotemporal variation and driving factors of vehicle emissions will be valuable for pollution control and public health protection. Here, taking polycyclic aromatic hydrocarbons (PAHs) as an example, a dynamic vehicle emission model (DVEM) was developed to assess vehicle emissions. The inventories of vehicle emissions from 2002 to 2017 were estimated under different emission standards and vehicle kilometers traveled for all types of vehicles in China. Vehicle PAHs emissions peaked 1586.85 tonne (t) in 2012 and declined by 36% in the follow-up five years because the vehicle growth has been offset by the upgraded emissions standards. There were remarkable variations among different provinces in China. The vehicle emissions are higher in eastern coastal provinces like Guangdong, Shandong, Jiangsu, and Zhejiang, while lower in the western provinces except Xinjiang. Motorcycles (44.1%) and light duty vehicles (17.8%) were the main contributors to PAHs emissions. The higher urbanization within a region, the larger its vehicle emission density. Urban road density may be linked with the number of on-road vehicles, which is the real driving factor of emissions. Therefore, integrated management should be taken by government to reduce the impacts of vehicle PAHs emissions. [Display omitted] • Major PAHs emissions were from LDV and Motorcycles. • Vehicle PAHs emission peaked in 2012 and declined in the follow-up five years. • Vehicle PAHs emissions in eastern China are significantly higher than the west. • Urban road density is the most important driving factor for vehicle emissions. • Integrated management should be strengthened to reduce vehicle PAHs emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Machine learning is used to build vehicle CO 2 and NO X transient models. • The models are trained on multiple vehicles and verified by a separate vehicle. • The input features of the models are more comprehensive than MOVES. • For CO 2 and NO X , how different model inputs affect the model results is analyzed. • Different models are constructed according to different pollutants. The transient simulation of CO 2 and NO X from motor vehicles has essential applications in evaluating vehicular greenhouse gas emissions and pollutant emissions. However, accurately estimating vehicular transient emissions is challenging due to the heterogeneity between different vehicles and the continuous upgrading of vehicle exhaust purification technology. To accurately characterize the transient emissions of motor vehicles, a Super-learner model is used to build CO 2 and NOx transient emission models. The actual onboard test data of 9 China VI N 2 vehicles were used to train the model, and the test data of another China VI N 2 vehicle were selected for further robustness verification. There were significant differences in the emissions between the vehicles, but the constructed transient model could capture the common law of transient emissions from China VI N 2 vehicles. The R2 values of CO 2 and NOx emission in the test data of the validation vehicle were 0.71 and 0.82, respectively. In addition, to further prove the model's robustness, the training data were synchronously modelled based on the Moves-method. The Super-learner model has a smaller RMSE on the validation set than the model based on the Moves-method, indicating that the Super-learner model has more transient simulation advantages. The marginal contributions of the model characteristics to the model results were analysed by SHapley Additive exPlanation (SHAP) value interpretation, and the marginal contributions of different pollutant characteristic parameters varied. Therefore, when establishing transient models of different pollutants, the selection of the model parameters demands considering the generation and purification process of different pollutants. The present work provides novel insights into the parameter selection, construction, and interpretation of the transient vehicle emission model. [ABSTRACT FROM AUTHOR]

In the high-speed railway industry, the pantograph-catenary system is responsible to provide continuous electric energy for the high-speed train. The pantograph-catenary system suffers multiple impacts from the complex work environment. The vehicle-track excitation is one of the normal disturbances to the pantograph-catenary interaction. Previous studies only consider the vertical effect of the vehicle-track vibration on the pantograph-catenary interaction. To address this deficiency, both of the pantograph-catenary and vehicle-track models are constructed in this paper. The validations of both models are verified by the experimental test and the world benchmark, respectively. The pantograph base follows the translations and rotations of the car-body caused by random rail irregularities. In combination with a spatial contact model between the contact wire and the pantograph strip, the spatial vibration of the carbody can be fully considered in the pantograph-catenary interaction. The statistical analysis, stochastic analysis and frequency analysis are performed to make sense of the effect of the random track irregularities on the pantograph-catenary interaction. The deviation of the contact point away from the strip centre caused by the carbody vibration is also analysed. The results show that the reliability of the pantograph-catenary system shows a continuous decrease in the degradation of rail quality. The carbody vibration may cause the de-wirement of the pantograph in extreme conditions. Finally, an application example is given to evaluate the dynamic performance of the pantograph-catenary system running on the China high-speed network with realistic rail irregularities. [ABSTRACT FROM AUTHOR]

To study the impact of the promotion of electric vehicles on carbon emissions in China, the full life carbon emissions of electric vehicles are studied on the basis of considering such factors as vehicle weight and grid mix composition, and fuel vehicles are added for comparison. In this paper, we collect data for 34 domestic electric vehicles, and linear regression analysis is used to model the relationship between vehicle weight and energy consumption. Then, a Hybrid Life Cycle Assessment method is used to establish the life cycle carbon emission calculation model for electric vehicles and fuel vehicles. Finally, the life cycle carbon emissions of electric vehicles and fuel vehicles under different electrical energy structures are discussed using scenario analysis. The results show that under the current grid mix composition in China, the carbon emissions of electric vehicles of the same vehicle weight class are 24% to 31% higher than that of fuel vehicles. As the proportion of clean energy in the grid mix composition increases, the advantages of electric vehicles to reduce carbon emissions will gradually emerge. [ABSTRACT FROM AUTHOR]