基于跟车思想的一维元胞自动机交通流模型

One-Dimensional Cellular Automaton Model of Traffic Flow Based on Car-Following Idea

提出一个改进的一维元胞自动机模型来模拟周期性边界条件下高速公路上车流运动· 基于跟车模型的思想 ,根据所研究车辆与其前方紧邻车辆之间的间距和相对速度来确定该车的运动 ,间接地反映了次近邻车辆的影响· 通过引入安全间距来描述高速运动车辆接近前方缓行车辆时的减速行为 ,并利用随机减速概率来反映减速行为中的随机因素· 由于安全间距的引入 ,当减速概率大于零时在较高密度下就出现完全的阻塞相· 同时在本模型中采用的是有条件减速 ,因而可以较好描述交通实测中观察到的现象· 在临界密度附近 ,车流运动处于亚稳态并呈现出滞后现象· 由于本模型对于车辆微观运动的合理描述 。

An improved one-dimensional CA traffic model was proposed to describe the highway traffic under the periodic boundary conditions. This model was based on the idea of the car-following model, which claims that the motion of a vehicle at one time step depends on both the its headway and the synchronous motion of the front vehicle, thus including indirectly the influence of its subneighboring vehicle. In addition, the so-called safety distance was introduced to consider the deceleration behavior of vehicles and the stochastic factor was taken into account by introducing the deceleration probability. Meanwhile, the conditional deceleration in the model gives a better description of the phenomena observed on highways. It is found that there exists the metastability and hysteresis effect of traffic flow in the neighborhood of critical density under different initial conditions. Since this model gives a reasonable depiction of the motion of a single vehicle, it is easy to be extended to the case of traffic flow under the control of traffic lights in cities.