Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies

Nanjing, China

Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies

Nanjing, China
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Jiang R.,Ningbo University | Zheng P.,Ningbo University | Zheng P.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies
Applied Mathematics and Mechanics (English Edition) | Year: 2017

Flow around an oscillating cylinder in a subcritical region are numerically studied with a lattice Boltzmann method (LBM). The effects of the Reynolds number, oscillation amplitude and frequency on the vortex wake modes and hydrodynamics forces on the cylinder surface are systematically investigated. Special attention is paid to the phenomenon of resonance induced by the cylinder oscillation. The results demonstrate that vortex shedding can be excited extensively under subcritical conditions, and the response region of vibration frequency broadens with increasing Reynolds number and oscillation amplitude. Two distinct types of vortex shedding regimes are observed. The first type of vortex shedding regime (VSR I) is excited at low frequencies close to the intrinsic frequency of flow, and the second type of vortex shedding regime (VSR II) occurs at high frequencies with the Reynolds number close to the critical value. In the VSR I, a pair of alternately rotating vortices are shed in the wake per oscillation cycle, and lock-in/synchronization occurs, while in the VSR II, two alternately rotating vortices are shed for several oscillation cycles, and the vortex shedding frequency is close to that of a stationary cylinder under the critical condition. The excitation mechanisms of the two types of vortex shedding modes are analyzed separately. © 2017 Shanghai University and Springer-Verlag Berlin Heidelberg


Cheng R.,Ningbo University | Cheng R.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Liu F.,Ningbo University | Liu F.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | And 2 more authors.
Nonlinear Dynamics | Year: 2017

In this paper, a new continuum model is developed based on full velocity difference car-following model, which takes the traffic jerk effect into account. The critical condition for traffic flow is derived, and density waves occur in traffic flow because of the small disturbance. Near the neutral stability line, nonlinear analysis is taken to derive the KdV–Burgers equation for describing the density wave, and one of the solutions is given. Numerical simulation is carried out to show the local traffic described by the model. © 2017 Springer Science+Business Media Dordrecht


Cheng R.,Ningbo University | Cheng R.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Ge H.,Ningbo University | Ge H.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Wang J.,Zhejiang University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2017

Considering the driver's timid and aggressive behaviors simultaneously, a new continuum model is put forwarded in this paper. By applying the linear stability theory, we presented the analysis of new model's linear stability. Through nonlinear analysis, the KdV–Burgers equation is derived to describe density wave near the neutral stability line. Numerical results verify that aggressive driving is better than timid act because the aggressive driver will adjust his speed timely according to the leading car's speed. The key improvement of this new model is that the timid driving deteriorates traffic stability while the aggressive driving will enhance traffic stability. The relationship of energy consumption between the aggressive and timid driving is also studied. Numerical results show that aggressive driver behavior can not only suppress the traffic congestion but also reduce the energy consumption. © 2017 Elsevier B.V.


Cheng R.,Ningbo University | Cheng R.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Ge H.,Ningbo University | Ge H.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Wang J.,Zhejiang University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2017

Considering effect of driver's memory during a period of time, an improved continuum model for traffic flow is proposed in this paper. By means of linear stability theory, the improved model's linear stability with driver's memory is obtained, which demonstrates that driver's memory have significant influence stability of traffic flow. The KdV–Burgers equation is deduced to describe the propagating behavior of traffic density wave near the neutral stability line by nonlinear analysis. Numerical results show that driver's memory has negative impact on stability of traffic flow, which will lead to traffic congestion. © 2017 Elsevier B.V.


Lu L.,Ningbo University | Lu L.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Wang J.,Purdue University | Zheng P.,Ningbo University | And 2 more authors.
PLoS ONE | Year: 2017

Among different stochastic user equilibrium (SUE) traffic assignment models, the Logit-based stochastic user equilibrium (SUE) is extensively investigated by researchers. It is constantly formulated as the low-level problem to describe the drivers' route choice behavior in bi-level problems such as network design, toll optimization et al. The Probit-based SUE model receives far less attention compared with Logit-based model albeit the assignment result is more consistent with drivers' behavior. It is well-known that due to the identical and irrelevant alternative (IIA) assumption, the Logit-based SUE model is incapable to deal with route overlapping problem and cannot account for perception variance with respect to trips. This paper aims to explore the network capacity with Probit-based traffic assignment model and investigate the differences of it is with Logit-based SUE traffic assignment models. The network capacity is formulated as a bi-level programming where the up-level program is to maximize the network capacity through optimizing input parameters (O-D multiplies and signal splits) while the low-level program is the Logit-based or Probit-based SUE problem formulated to model the drivers' route choice. A heuristic algorithm based on sensitivity analysis of SUE problem is detailed presented to solve the proposed bi-level program. Three numerical example networks are used to discuss the differences of network capacity between Logit-based SUE constraint and Probit-based SUE constraint. This study finds that while the network capacity show different results between Probit-based SUE and Logit-based SUE constraints, the variation pattern of network capacity with respect to increased level of travelers' information for general network under the two type of SUE problems is the same, and with certain level of travelers' information, both of them can achieve the same maximum network capacity. © 2017 Lu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Cheng R.,Ningbo University | Cheng R.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Ge H.,Ningbo University | Ge H.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Wang J.,Zhejiang University
Physica A: Statistical Mechanics and its Applications | Year: 2017

In this paper, a new continuum model based on full velocity difference car following model is developed with the consideration of driver's anticipation effect. By applying the linear stability theory, the new model's linear stability is obtained. Through nonlinear analysis, the KdV–Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line. Numerical simulation shows that the new model possesses the local cluster, and it is capable of explaining some particular traffic phenomena Numerical results show that when considering the effects of anticipation, the traffic jams can be suppressed efficiently. The key improvement of this new model is that the anticipation effect can improve the stability of traffic flow. © 2017 Elsevier B.V.


Cheng R.,Ningbo University | Cheng R.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Ge H.,Ningbo University | Ge H.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Wang J.,Zhejiang University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2017

Due to the maximum velocity and safe headway distance of the different vehicles are not exactly the same, an extended macro model of traffic flow with the consideration of multiple optimal velocity functions with probabilities is proposed in this paper. By means of linear stability theory, the new model's linear stability condition considering multiple probabilities optimal velocity is obtained. The KdV–Burgers equation is derived to describe the propagating behavior of traffic density wave near the neutral stability line through nonlinear analysis. The numerical simulations of influences of multiple maximum velocities and multiple safety distances on model's stability and traffic capacity are carried out. The cases of two different kinds of maximum speeds with same safe headway distance, two different types of safe headway distances with same maximum speed and two different max velocities and two different time-gaps are all explored by numerical simulations. First cases demonstrate that when the proportion of vehicles with a larger vmax increase, the traffic tends to unstable, which also means that jerk and brakes is not conducive to traffic stability and easier to result in stop and go phenomenon. Second cases show that when the proportion of vehicles with greater safety spacing increases, the traffic tends to be unstable, which also means that too cautious assumptions or weak driving skill is not conducive to traffic stability. Last cases indicate that increase of maximum speed is not conducive to traffic stability, while reduction of the safe headway distance is conducive to traffic stability. Numerical simulation manifests that the mixed driving and traffic diversion does not have effect on the traffic capacity when traffic density is low or heavy. Numerical results also show that mixed driving should be chosen to increase the traffic capacity when the traffic density is lower, while the traffic diversion should be chosen to increase the traffic capacity when the traffic density is heavier. © 2017 Elsevier B.V.


Lu L.,Ningbo University | Lu L.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Ren G.,Nanjing Southeast University | Wang W.,Nanjing Southeast University | And 2 more authors.
Accident Analysis and Prevention | Year: 2016

At unsignalized crosswalks, interactions between pedestrians and vehicles often lead to traffic safety hazards due to absence of traffic control and unclear right-of-ways. To address this safety problem, there is a need to understand the interaction behaviors of pedestrians and vehicles that are complicated by a variety of traffic and roadway attributes. The prime objective of this study is to establish a reliable simulation model to represent the vehicle yielding and pedestrian crossing behaviors at unsignalized crosswalks in a realistic way. The model is calibrated with detailed behavioral data collected and extracted from field observations. The capability of the calibrated model in predicting the pedestrian-interaction events as well as estimating the driver yielding rate and pedestrian delay are also tested and demonstrated. Meanwhile, the traffic dynamics in the vicinity of the crosswalk can be meaningfully represented with simulation results based on the model. Moreover, with the definitions of the vehicle-pedestrian conflicts, the proposed model is capable to evaluate the pedestrian safety. Thereby, the simulation model has the potential to serve as a useful tool for assessing safety performance and traffic operations at existing facilities. Furthermore, the model can enable the evaluation of policy effectiveness and the selection of engineering treatments at unsignalized crosswalks to improve safety and efficiency of pedestrian crossing. © 2016 Elsevier Ltd.


Cui Y.,Ningbo University | Cheng R.-J.,Zhejiang University | Ge H.-X.,Ningbo University | Ge H.-X.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies
Nonlinear Dynamics | Year: 2014

Based on single-lane traffic model, a two-lane traffic model is presented considering the velocity difference control signal. The stability condition of the model is obtained by the control theory. The delayed feedback control signal is added to the two-lane model, and the corresponding stability condition is derived again. The numerical simulations show that as the stability conditions are satisfied, the small disturbance will not amplify with and without control signal. In the meantime, the stability is strengthened as the control signal is considered. So the control signal would suppress the traffic disturbance successfully. © 2014, Springer Science+Business Media Dordrecht.


Ge H.-X.,Ningbo University | Ge H.-X.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | Zheng P.-J.,Ningbo University | Zheng P.-J.,Jiangsu Province Collaborative Innovation Center for Modern Urban Traffic Technologies | And 2 more authors.
Physica A: Statistical Mechanics and its Applications | Year: 2015

Based on optimal velocity car following model, a new model considering traffic jerk is proposed to describe the jamming transition in traffic flow on a highway. Traffic jerk means the sudden braking and acceleration of vehicles, which has a significant impact on traffic movement. The nature of the model is researched by using linear and nonlinear analysis method. A thermodynamic theory is formulated to describe the phase transition and critical phenomenon in traffic flow. The time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived to describe the traffic flow near the critical point and the traffic jam. In addition, the connection between the TDGL and the mKdV equations are also given. © 2015 Published by Elsevier B.V.

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