共查询到19条相似文献,搜索用时 125 毫秒
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运用具有内、外环道的平面环形交叉路口元胞自动机模型,利用交通流基本图从瓶颈的角度研究了车道尺度对平面环行交叉路口交通流的影响。计算机模拟结果表明:同步增加内、外环道长度时,内环道流量将会增加;同步增加入、出环车道长度时,内环道流量保持不变。 相似文献
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本文以右转机动车和直行自行车为对象研究交叉口混合交通流特性.基于交叉口机非干扰特性,将机动车元胞模型和自行车元胞模型进行了耦合,建立了考虑自行车穿越机动车延时、机动车穿越自行车间隙和冲突区占据处置等规则的交叉口混合交通流元胞自动机模型(NS-BCA).对右转机动车与直行自行车混合交通流进行了仿真,从流量-车辆到达率关系、交通流相位相变、交通流相位-到达率-混合交通流状态等方面研究了交叉口混合交通流的机非干扰机理. 相似文献
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在NaSh模型的基础上,考虑交通事故和养护路段等意外事件对高速公路交通流的影响,建立了有意外事件影响的在车道管制下的高速公路交通流元胞自动机模型,并进行数值模拟. 研究发现:意外事件对高速公路交通流有明显影响,并且意外事件对交通流的影响在某一密度值范围内尤其明显,且意外事件堵塞点在第一车道比在第二车道对交通流的影响小;同时,在该密度值范围内,意外事件堵塞时间和堵塞路段长度越长,对交通流的影响就越大.
关键词:
元胞自动机
交通流
意外事件 相似文献
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在Nagel-Schreckenberg(NS)模型的基础上,提出一种可应用智能交通系统(ITS)信息的新的交通流元胞自动机模型. 其中考虑了有效间距及刹车灯的作用,并引入了可变安全间距的新概念. 数值模拟表明:对于这种改进的ITS元胞自动机模型,道路交通量有了显著提高,体现了智能交通的优越性——有效地扩大交通流量,减少阻塞生成. 当考虑快车和慢车的混合交通流时,发现即使少量的慢车也会导致交通流量大幅度下降,说明了严格实施快慢道行驶的必要性.
关键词:
交通流
智能交通系统(ITS)
元胞自动机模型
刹车灯
可变安全间距 相似文献
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The effect of stochastic accelerating and delay probability with the velocity and the gap between vehicles on traffic flow 下载免费PDF全文
This paper proposes a new combined cellular automaton (CA) model
considering the driver behavior of stochastic acceleration and delay
with the velocity of the preceding vehicle and the gap between the
successive vehicles based on the WWH model and the noise-first NaSch
model. It introduces the delay probability varying with the gap,
adds the anticipation headway and increases the acceleration with a
certain probability. Through these simulations, not only can the
metastable state and start--stop wave be obtained but also the synchronized flow
which the wide moving jam results in. Moreover, the
effect of stochastic acceleration and delay on traffic flow is
discussed by analyzing the correlation of traffic data. This indicates
that synchronized flow easily emerges in the critical area between
free flow and synchronized flow when acceleration and delay are
synchronized or their probability is close to 0.5. 相似文献
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在经典单路段元胞自动机交通流模型的基础上,将多个路段视为一个道路系统,提出并研究了多路段条件下的交通流问题.针对多路段道路的特点,通过引入车辆流入规则、路口随机慢化规则和路口车辆流入规则,控制车辆从上一路段流入下一路段.首先提出了"汽车池"的概念,来控制每一路口车辆的流入;然后通过路口随机慢化,来模拟路口对交通的影响;最后,当车辆离开时,依直行率进入下一路段,实现车流的继续流动.同时,通过数值模拟,仿真了不同条件下的交通情况,对重要参数进行了研究.结果表明,出现了混合流这一新的现象,拥堵地段与非拥堵地段间存在明显的界限.拥堵往往最先从路口开始,然后蔓延到整个路段.多路段道路还存在临界突变的特性.随着车辆流入概率的增大,路口对平均速度和车流密度的影响愈加明显.当流入概率超过一定阈值时,车辆缓慢地增加也会引起整体道路通行能力的迅速下降. 相似文献
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A new cellular automata model of traffic flow with negative exponential weighted look-ahead potential 下载免费PDF全文
With the development of traffic systems, some issues such as traffic jams become more and more serious. Efficient traffic flow theory is needed to guide the overall controlling, organizing and management of traffic systems. On the basis of the cellular automata model and the traffic flow model with look-ahead potential, a new cellular automata traffic flow model with negative exponential weighted look-ahead potential is presented in this paper. By introducing the negative exponential weighting coefficient into the look-ahead potential and endowing the potential of vehicles closer to the driver with a greater coefficient, the modeling process is more suitable for the driver's random decision-making process which is based on the traffic environment that the driver is facing. The fundamental diagrams for different weighting parameters are obtained by using numerical simulations which show that the negative exponential weighting coefficient has an obvious effect on high density traffic flux. The complex high density non-linear traffic behavior is also reproduced by numerical simulations. 相似文献
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Based on simulations with cellular automaton (CA) traffic flow models, a generic physical feature of the three-phase models studied in the paper is disclosed. The generic feature is a discontinuous character of driver over-acceleration caused by a combination of two qualitatively different mechanisms of over-acceleration: (i) Over-acceleration through lane changing to a faster lane, (ii) over-acceleration occurring in car-following without lane changing. Based on this generic feature a new three-phase CA traffic flow model is developed. This CA model explains the set of the fundamental empirical features of traffic breakdown in real heterogeneous traffic flow consisting of passenger vehicles and trucks. The model simulates also quantitative traffic pattern characteristics as measured in real heterogeneous flow. 相似文献
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在Nagel Schrekenberg单车道元胞自动机交通流模型(简称NS模型)的基础上,考虑车辆之间的相对运动薛郁等提出了一种改进的单车道元胞自动机交通流模型(简称改进的NS模型).通过两种情况列出了改进的NS模型存在不尽周严的地方,随之在新模型中引入了行车状态 变量和反馈规则,从而控制车辆出现倒车和刹车过急等现象.通过计算机对新模型进行模拟 ,发现减速概率和车流密度对车流状态的演化影响很大,当减速概率高(如道路条件差)时 ,即使车流密度低,车流也会出现局部堵塞状态;而当减速概率一定时,随着车流密度增加 ,车流的运动相与堵塞相发生了全局性的交替出现,此时类似于波的波峰和波谷的传播.与 改进的NS模型相比较,新模型模拟的车流量较高,说明新模型减少了车流的总体停滞状态.
关键词:
交通流
元胞自动机
行车状态
反馈规则 相似文献
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This paper uses the cellular automaton model to study the
dynamics of traffic flow around an on-ramp with an acceleration lane.
It adopts a parameter, which can reflect different lane-changing
behaviour, to represent the diversity of driving behaviour. The
refined cellular automaton model is used to describe the lower
acceleration rate of a vehicle. The phase diagram and the capacity of the
on-ramp system are investigated. The simulation results show that in
the single cell model, the capacity of the on-ramp system will stay
at the highest flow of a one lane system when the driver is moderate
and careful; it will be reduced when the driver is aggressive. In
the refined cellular automaton model, the capacity is always reduced
even when the driver is careful. It proposes that the capacity drop of
the on-ramp system is caused by aggressive lane-changing behaviour
and lower acceleration rate. 相似文献
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Analysis of the influence of occupation rate of public transit vehicles on mixing traffic flow in a two-lane system 下载免费PDF全文
Based on the existing classical cellular automaton model of traffic
flow, a cellular automaton traffic model with
different-maximum-speed vehicles mixed on a single lane is proposed,
in which public transit and harbour-shaped bus stops are
taken into consideration. Parameters such as length of cellular
automaton, operation speed and random slow mechanism are
re-demarcated. A harbour-shaped bus stop is set up and the vehicle changing
lane regulation is changed. Through computer simulation, the
influence of occupation rate of public transit vehicles on mixed
traffic flow and traffic capacity is analysed. The results show that
a public transport system can ease urban traffic congestion
but creates new jams at the same time, and that the influence of
occupation rate of public transit vehicles on traffic capacity is
considerable. To develop urban traffic, attention should be paid
to the occupation rate of public transit vehicles and traffic
development in a haphazard way should be strictly avoided. 相似文献
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在行人流量大的人行横道处,机动车和行人之间存在较为严重的干扰.通过引入行人和机动车的冲突干扰规则, 构建了能够刻画人行横道处机动车和行人相互干扰行为的元胞自动机模型.通过数值模拟研究了行人到达率、机动车到达率、 行人冒险穿越机动车道的阈值以及行人对机动车敏感系数等因素对机动车和行人流量的影响. 模拟结果显示,所提出的模型很好地反映了行人与机动车之间的干扰特性;随着行人冒险穿越机动车道的阈值的增加, 机动车流量增大,行人流量减小;随着行人对机动车敏感系数的增加,行人避让概率减小,机动车流量减小,行人流量增大. 所得结果对混合交通的控制和管理具有一定的指导意义. 相似文献