With the sustained and rapid development of China’s national economy, the number of motor vehicles owned by families in cities is rapidly growing. Consequently, problems of traffic congestion and air pollution have also appeared in these cities. Roadside parking traffic has also become an important part of the transportation system in cities. However, there is no specific measurement model for carbon emissions caused by roadside parking in the proposed traffic carbon emission model. Therefore, we aim to establish a carbon emission measurement model for roadside parking. In this paper, we first study the characteristics of the deceleration and maneuvering of parking vehicles and the blocking impact on running vehicles in a typical roadside parking scenario. We then establish and fit models of the direct and indirect carbon emissions during roadside parking. Based on the carbon emission model, we propose a calculation method for roadside parking carbon emissions, including accounting and estimation methods. These models can be used to calculate the carbon emissions from roadside parking in a traffic carbon emissions system. We also hope that these models will help future research on the optimization of roadside parking facilities for energy saving and emission reduction.

For the cooperative adaptive cruise control (CACC) vehicular platoon, apart from decentralized controllers, the dynamics of a platoon can be affected substantially by the information flow among connected and automated vehicles (CAVs). Existing research studies mainly focus on the stability analysis of platoons where CAVs only adopt the predecessor-following (PF) communication scheme; however, when CAVs “look” further ahead or behind than one vehicle, the stability of platoons might change. To this end, this study seeks to explore the stability and investigate the rear-end collision risk of CACC vehicular platoon under diverse information flow topologies. The research first comprehensively reviews typical information flow topologies for CAV platoons and platoon stability criteria for analyzing local and string stability of platoons. Moreover, the CACC longitudinal dynamic model is derived using the exact feedback linearization technique, which accommodates the inertial delay of powertrain dynamics. Accordingly, sufficient conditions of stability are mathematically derived to guarantee distributed frequency-domain-based control parameters. Simulation experiments are conducted to verify the correctness of derived sufficient stability conditions. The results show that platoons could better maintain stability with more vehicle information taken into consideration. However, when assessing the safety, it is found that the bidirectional type information flow topology would increase rear-end collision risk for CAV platoon. Further, the information flow topology of two-predecessor-leader following is the most recommended to enhance fully CAV platoon stability.

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This paper aims to improve transfer utility between bike-sharing and subway. For this paper, the transfer costs of three combined travel modes were analyzed, including “Bike-sharing + Subway”, “Walking + Subway” and “Bus + Subway”, and a transfer cost function, including time cost and expense cost, was constructed. Cluster analysis was carried out on the origin and destination of bike-sharing in the transfer-influenced area. The sum of squares of errors and the service radius were used to verify the clustering results. Then the number of alternative facilities, the location of alternative facilities and the initial number of shared bikes were preliminarily predicted. Based on the initial scheme, a bi-level programming model of facility layout and configuration in bike-sharing was established, with the goal of improving ride volume and reducing the transfer cost and facility-operation costs to optimize the initial facility-allocation scheme. Then a heuristic algorithm was used to solve the model. Finally, a typical subway station was selected as a case, and the configuration process for facilities in bike-sharing is discussed in detail in the paper. The research results of this paper may provide reference for the planning and optimization adjustments of facilities for bike-sharing.

The advent of vehicle-to-everything (V2X) communication technology, as well as driving automation that is happening at a rapid pace, enables the potential for transforming the transportation system. The near future will, therefore, bring the coexistence of human-driven vehicles (HVs), connected vehicles (CVs), and connected and automated vehicles (CAVs). Correspondingly, platoon management based on V2X communication is expected to improve traffic capacity and fuel efficiency. However, there is a lack of analysis of the impact of platoon management on heterogeneous traffic combined with CVs. Moreover, V2X communication limitation is usually dismissed in existing studies. To address these limitations, this paper explores the impact of platoon management on the capacity of heterogeneous-traffic environments under different CV and CAV market penetration rates (MPRs) with the fundamental diagram considering V2X communication limitations, and further studies the changes in capacity and fuel efficiency of traffic combined with different platoon sizes. Firstly, in light of platoon management, we propose the heterogeneous traffic configurations through distribution characteristics of nine types with simulated models. Secondly, the fundamental diagram considering platoon management with V2X communication limitation is proposed under different CV and CAV MPRs. Thirdly, numerical simulations are conducted to demonstrate the impact of platoon size on the changes in capacity and fuel efficiency of traffic. Conclusions are drawn from the results of the simulations: with the cooperation of CVs and CAVs, the traffic capacity and the fuel efficiency will be promoted, particularly under high CV MPR or high CAV MPR environments.