scholarly journals An Improved Macro Model of Traffic Flow with the Consideration of Ramps and Numerical Tests

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhongke Shi ◽  
Wenhuan Ai ◽  
Dawei Liu
Keyword(s):  
Traffic Flow ◽  
Phase Plane ◽  
Macro Model ◽  
Traffic Jams ◽  
Numerical Tests ◽  
Stop And Go ◽  
Point Equation ◽  
Improved Model ◽  
The Relationship ◽  
Real Traffic

We present an improved macro model for traffic flow based on the existing models. The equilibrium point equation of the model is obtained. The stop-and-go traffic phenomenon is described in phase plane and the relationship between traffic jams and system instability is clearly shown in the phase plane diagrams. Using the improved model, some traffic phenomena on a highway with ramps are found in this paper. The numerical simulation is carried out to investigate various nonlinear traffic phenomena with a single ramp generated by different initial densities and vehicle generation rates. According to the actual road sections of Xi’an-Baoji highways, the situations of morning peak with several ramps are also analyzed. All these results are consistent with real traffic, which shows that the improved model is reasonable.

scholarly journals Phase Plane Analysis Method of Nonlinear Traffic Phenomena

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Wenhuan Ai ◽  
Zhongke Shi ◽  
Dawei Liu
Keyword(s):  
Traffic Flow ◽  
Phase Plane ◽  
System Stability ◽  
Phase Plane Analysis ◽  
Analysis Method ◽  
Rarefaction Waves ◽  
New Model ◽  
Plane Analysis ◽  
Stop And Go ◽  
The Relationship

A new phase plane analysis method for analyzing the complex nonlinear traffic phenomena is presented in this paper. This method makes use of variable substitution to transform a traditional traffic flow model into a new model which is suitable for the analysis in phase plane. According to the new model, various traffic phenomena, such as the well-known shock waves, rarefaction waves, and stop-and-go waves, are analyzed in the phase plane. From the phase plane diagrams, we can see the relationship between traffic jams and system instability. So the problem of traffic flow could be converted into that of system stability. The results show that the traffic phenomena described by the new method is consistent with that described by traditional methods. Moreover, the phase plane analysis highlights the unstable traffic phenomena we are chiefly concerned about and describes the variation of density or velocity with time or sections more clearly.

scholarly journals A New Macro Model Considering the Average Speed of Preceding Vehicles Group in CPS Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Yi-rong Kang ◽  
Di-hua Sun ◽  
Shu-hong Yang
Keyword(s):  
Traffic Flow ◽  
Linear Stability ◽  
Linear Stability Theory ◽  
Average Speed ◽  
Car Following ◽  
Macro Model ◽  
Car Following Model ◽  
Macro Variables ◽  
The Relationship ◽  
Real Traffic

A new car following model considering the effect of average speed information of preceding vehicles group in real traffic is presented. Based on the new car following model, a new macro model for traffic flow is proposed employing the relationship between the micro and macro variables. The linear stability condition of the macro model is obtained by using the linear stability theory. The numerical tests show that the new model can not only simulate the dynamic process of shock, rarefaction wave, and small perturbation, but also can further stabilize the traffic flow.

Macroscopic modeling for traffic flow on three-lane highways

2015 ◽  
Vol 26 (11) ◽  
pp. 1550127 ◽  
Author(s):  
Jianzhong Chen ◽  
Yuan Fang
Keyword(s):  
Traffic Flow ◽  
Present Model ◽  
Rarefaction Waves ◽  
Lane Changing ◽  
Change Rate ◽  
Macroscopic Modeling ◽  
Continuity Equations ◽  
Stop And Go ◽  
Real Traffic ◽  
Inversion Phenomenon

In this paper, a macroscopic traffic flow model for three-lane highways is proposed. The model is an extension of the speed gradient model by taking into account the lane changing. The new source and sink terms of lane change rate are added into the continuity equations and the speed dynamic equations to describe the lane-changing behavior. The result of the steady state analysis shows that our model can describe the lane usage inversion phenomenon. The numerical results demonstrate that the present model effectively reproduces several traffic phenomena observed in real traffic such as shock and rarefaction waves, stop-and-go waves and local clusters.

STABILITY ANALYSIS FOR TRAFFIC FLOW WITH PERTURBATIONS

2008 ◽  
Vol 19 (09) ◽  
pp. 1367-1375 ◽  
Author(s):  
TIE-QIAO TANG ◽  
HAI-JUN HUANG ◽  
YING ZHANG ◽  
XIANG-YANG XU
Keyword(s):  
Traffic Flow ◽  
Initial Density ◽  
Local Cluster ◽  
Small Perturbations ◽  
Gradient Model ◽  
Stop And Go ◽  
The Stability ◽  
Very High ◽  
Real Traffic ◽  
Speed Gradient

In this paper, we use the speed-gradient model proposed by Jiang et al. [Transp. Res. B36, 405 (2002)] to study the effects that various perturbations have on the stability of traffic flow. Our numerical tests show that the effects of perturbations on the stability of traffic flow are related to the initial density, i.e., when the initial density is very low (ρ0 ≤ 0.02) or very high (ρ0 > 0.08), any perturbation has little effect on the stability of traffic flow; when the initial density is relatively low (0.02 < ρ0 ≤ 0.04), small perturbations have little effect on the stability of traffic flow and large perturbations will have effect on it and produce local cluster; when the initial density is relatively high (0.04 < ρ0 ≤ 0.08), any perturbation will have great effect on the stability of traffic flow and produce stop-and-go traffic. These results are completely accordant with the real traffic, which just shows that the speed-gradient model can be used to perfectly explore the consequences caused by various perturbations.

A New Macro Model for Traffic Flow on a Highway with Ramps and Numerical Tests

2009 ◽  
Vol 51 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Tang Tie-Qiao ◽  
Huang Hai-Jun ◽  
S.C Wong ◽  
Gao Zi-You ◽  
Zhang Ying
Keyword(s):  
Traffic Flow ◽  
Macro Model ◽  
Numerical Tests

THE EFFECTS OF BUS STOP ON TRAFFIC FLOW

2009 ◽  
Vol 20 (06) ◽  
pp. 941-952 ◽  
Author(s):  
TIE-QIAO TANG ◽  
YAN LI ◽  
HAI-JUN HUANG
Keyword(s):  
Traffic Flow ◽  
Flow Model ◽  
Initial Density ◽  
Numerical Results ◽  
Traffic Flow Model ◽  
The Real ◽  
Bus Stop ◽  
Numerical Tests ◽  
The Stability ◽  
Real Traffic

In this paper, we use the traffic flow model proposed by Tang et al. [Physica A387, 6845 (2008)] to study the effects of bus stop on traffic flow. Our numerical tests show that bus stop will have great effects on the stability of traffic flow and that the effects are related to the initial density and the number of bus stops. The numerical results are accordant with the real traffic, which shows that the model proposed by Tang et al. can describe some complex traffic phenomena resulted by bus stop.

scholarly journals A Cellular Automaton Traffic Flow Model with Advanced Decelerations

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Yingdong Liu
Keyword(s):  
Cellular Automaton ◽  
Traffic Flow ◽  
Flow Model ◽  
Stable State ◽  
Practical Significance ◽  
Fundamental Diagram ◽  
Traffic Flow Model ◽  
Short Time ◽  
Vehicle Deceleration ◽  
Real Traffic

A one-dimensional cellular automaton traffic flow model, which considers the deceleration in advance, is addressed in this paper. The model reflects the situation in the real traffic that drivers usually adjust the current velocity by forecasting its velocities in a short time of future, in order to avoid the sharp deceleration. The fundamental diagram obtained by simulation shows the ability of this model to capture the essential features of traffic flow, for example, synchronized flow, meta-stable state, and phase separation at the high density. Contrasting with the simulation results of the VE model, this model shows a higher maximum flux closer to the measured data, more stability, more efficient dissolving blockage, lower vehicle deceleration, and more reasonable distribution of vehicles. The results indicate that advanced deceleration has an important impact on traffic flow, and this model has some practical significance as the result matching to the actual situation.

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