1 简介
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.
2 部分代码
% main.m
%
% This is a main script to simulate the approach, service, and departure of
% vehicles passing through a toll plaza, , as governed by the parameters
% defined below
%
% iterations = the maximal iterations of simulation
% B = number booths
% L = number lanes in highway before and after plaza
% Arrival = the mean total number of cars that arrives
% plazalength = length of the plaza
% Service = Service rate of booth
% plaza = plaza matrix
% 1 = car, 0 = empty, -1 = forbid, -3 = empty&booth
% v = velocity matrix
% vmax = max speed of car
% time = time matrix, to trace the time that the car cost to
% pass the plaza.
% dt = time step
% t_h = time factor
% departurescount = number of cars that departure the plaza in the step
% departurestime = time cost of the departure cars
% influx = influx vector
% outflux = outflux vector
% timecost = time cost of all car
% h = handle of the graphics
%
% zhou lvwen: zhou.lv.wen@gmail.com
clear;clc
iterations = 1200; % the maximal iterations of simulation
B = 3; % number booths
L = 3; % number lanes in highway before and after plaza
Arrival=3; % the mean total number of cars that arrives
plazalength = 81; % length of the plaza
[plaza, v, time,buspla] = create_plaza(B, L, plazalength);
h = show_plaza(plaza,buspla, NaN, 0.01);
timeblock=5;
dt = 0.2; % time step
t_h = 1; % time factor
vmax = 2; % max speed
vinit=1;%initial speed
busstop=6*ones(plazalength,B+2);
carstop=3*ones(plazalength,B+2);
timecost = [];
sf=0;%switchflag
for i = 1:iterations
if i==14
ss=0;
end
if i==370
ss=0;
end
if i==490
ss=0;
end
if i==550
ss=0;
end
if i==602
ss=0;
end
if i==711
ss=0;
end
% introduce new cars
[plaza, v, arrivalscount] = new_cars(Arrival, dt, plaza, v, vinit,i);
[plaza, v, buspla] = new_bus(plaza, v, vinit, i,buspla);
h = show_plaza(plaza,buspla, h, 0.02);
[timeblock,plaza] = carblock(timeblock,plaza,sf);%转向导致堵车
% update rules for lanes
r=rand();
if(r<0.3)
[plaza, v, time,buspla,busstop,carstop,sf] = switch_lanes(plaza, v, time,buspla,busstop,carstop,sf); % lane changes
[plaza, v, time,buspla] = move_forward(plaza, v, time, vmax,buspla); % move cars forward
else
[plaza, v, time,buspla] = move_forward(plaza, v, time, vmax,buspla); % move cars forward
[plaza, v, time,buspla,busstop,carstop,sf] = switch_lanes(plaza, v, time,buspla,busstop,carstop,sf); % lane changes
end
[plaza,buspla, v, time, departurescount, departurestime] = clear_boundary(plaza,buspla, v, time);
% flux calculations
influx(i) = arrivalscount;
outflux(i) = departurescount;
timecost = [timecost, departurestime];
end
h = show_plaza(plaza, h, 0.01);
pause
xlabel({strcat('B = ',num2str(B)), ...
strcat('mean cost time = ', num2str(round(mean(timecost))))})
3 仿真结果
4 参考文献
[1]刘茂桂, 吴珊珊, 傅盛杰. 基于元胞自动机的高速公路交通事故仿真研究[J]. 数字化用户, 2014, 20(010):51.
**部分理论引用网络文献，若有侵权联系博主删除。**
