高速公路匝道交织区交通流仿真与事故特征研究

发布时间：2018-10-08 15:02

【摘要】：高速公路有着快捷、高效、方便、舒适、运输成本低等特点,现在已经成为我国综合交通运输系统的不可或缺的一个组成部分。匝道交织区不仅是高速公路的一个重要组成部分,而且也是高速公路的重要瓶颈路段。上匝道下游不远处紧接着一个下匝道并且两匝道之间距离较近时,在这两个匝道之间会形成一个交织区。在交织区内也是车辆之间容易发生冲突的区域。部分车辆需要在这非常有限的区域内完成交织换道行为。有时还会因为没有适当的空隙完成交织行为,部分驾驶员会选择强制换道。不论是强制换道还是正常的换道,都会对交织区处的车流造成干扰,使得车流呈高速紊乱状态,容易造成交通事故,使高速公路产生拥堵,危害人民群众生命及财产安全。因此,研究高速公路匝道交织区系统交通流的一些特性以及交通事故特征,对减少高速公路交通事故具有重要意义。本文在借鉴和吸收国内外学术研究成果的基础上,以元胞自动机理论、交通冲突理论以及交通流理论为指导,以经典的NaSch模型为基础,以Matlab计算机平台为主要仿真方法,建立了高速公路匝道交织区元胞自动机模型,并模拟了参数为a2=0.2,Poff=0.2时系统总流量与a1的关系;在得出并分析系统总流量与匝道进车概率a1关系的基础上,结合系统总流量讨论了在自由流和饱和流状态下连续刹车率与a1的关系、换道比例与a1的关系和交织区系统内强制换道比例与a1的关系。论文的主要研究内容及成果如下:(1)首先利用交通冲突理论对高速公路匝道交织区交通事故类型进行理论分析,并将高速公路匝道交织区处发生的事故类型主要分为追尾、侧撞与撞固定物体等三种类型。其次通过网络渠道搜集高速公路匝道交织区交通事故并对其原因进行分析。最后根据交通事故原因对驾驶员与管理者提出建议。(2)建立了基于元胞自动机的高速公路匝道交织区仿真模型。分析了在不同匝道进车及匝道驶出概率条件下,交织区系统总流量qall与a1之间的关系,研究发现:交织区系统总流量在主路进车概率a1=0.4时开始趋于饱和状态;在匝道进车概率相同的情况下,随着匝道出车概率的增加,系统饱和流量值增加;在匝道驶出概率相同的情况下,随着匝道进车概率的增加,系统饱和流量值减小。(3)在分析了交通事故原因的基础上,分析了系统总流量处于自由流和饱和流状态下的系统内连续刹车率、换道比例及强制换道比例的变化情况。发现,在相同的进车概率条件下:(1)系统流量处于自由流状态时:不同匝道驶出概率所对应的连续刹车率都平缓上升,但是匝道驶出率高时所对应的连续刹车率值要高于匝道驶出概率低时所对应的连续刹车率值;不同匝道驶出概率所对应的强制换道比例都等于零。(2)系统流量处于饱和流状态时:不同匝道驶出概率所对应的连续刹车率都急剧上升后趋于稳定状态,但是匝道驶出率高时所对应的连续刹车率值也高于匝道驶出概率低时所对应的连续刹车率值;此时强制换道比例也急剧上升后趋于稳定状态,随着匝道驶出概率的增加而增加。匝道驶出概率相同时:(1)系统总流量处于自由流状态时:不同的匝道进车概率所对应的连续刹都车平缓上升,然而不同匝道进车概率对连续刹车率的影响并不大;不同匝道进车概率所对应的强制换道比例都等于零。(2)系统流量处于饱和流状态时:不同匝道进车概率所对应的连续刹车率都急剧上升后趋于稳定状态,但是匝道进车率高时所对应的连续刹车率值低于匝道驶出概率低时所对应的连续刹车率值;此时强制换道比例也急剧上升后趋于稳定状态,随着匝道进车概率的增加而增加。
[Abstract]:The expressway has the characteristics of shortcut, high efficiency, convenience, comfort, low transportation cost and so on. It has become an indispensable part of the comprehensive transportation system in China. The ramp interleaving area is not only an important part of the expressway, but also an important bottleneck road section of the expressway. An interleaving area is formed between the two ramps immediately following the next ramp downstream of the ramp and closer to the two ramps. Areas that are prone to conflict between vehicles are also within the interleaving area. Some vehicles need to complete the interleaving behavior in this very limited area. Sometimes, because there is no appropriate clearance to complete the interleaving behavior, some drivers will choose to force the lane. Whether forced switching or normal lane change can interfere with the traffic flow at the interleaving area, so that the traffic flow is in a high-speed disturbance state, traffic accidents can be easily caused, congestion on the expressway is caused, and the life and property safety of the people are endangered. Therefore, it is of great significance to study some characteristics of traffic flow and traffic accident characteristics of freeway ramp-crossing system. On the basis of reference and absorption of academic research achievements at home and abroad, this paper takes the theory of meta-cellular automata, traffic conflict theory and traffic flow theory as the guidance, based on the classic NaSch model, and takes the Matlab computer platform as the main simulation method. On the basis of obtaining and analyzing the relation between the total flow of the system and the ramp-in vehicle probability a1, The relation between the continuous brake rate and a1 in free flow and saturated flow condition, the relationship between the change ratio and a1 and the relationship between the forced commutation ratio and a1 in the interleaving area system are discussed in combination with the total flow of the system. The main contents and achievements of the thesis are as follows: (1) Firstly, the traffic conflict theory is used to analyze the traffic accident types of the freeway ramp, and the types of accidents at the intersection of the ramp are mainly divided into rear-end collision. Three types of side impact and collision fixed objects. Secondly, the traffic accidents of the freeway ramp are collected through the network channel, and the reasons are analyzed. Finally, the driver and the manager make suggestions according to the cause of the traffic accident. (2) The simulation model of freeway ramp interleaving area based on meta-cellular automata is established. Based on the analysis of the relationship between the total flow qall and a1 of the cross-section system at different ramp-in vehicles and ramp-out probability conditions, it is found that the total flow of the interlaced zone system begins to become saturated when the main road enters the vehicle's probability a1 = 0.4, and in the case of the same probability of the ramp-in vehicle, With the increase of ramp-off probability, the saturation flow value of the system increases, and with the increase of the ramp-in probability, the system saturation flow value decreases. (3) On the basis of analyzing the cause of traffic accident, the change of continuous brake rate, change ratio and forced commutation ratio in the system under the condition of free flow and saturated flow is analyzed. It is found that under the same vehicle probability condition: (1) When the system flow is in the free flow state, the continuous braking rate corresponding to the departure probability of different ramps rises smoothly. However, the corresponding continuous braking rate value when the ramp-off rate is high is higher than the corresponding continuous brake rate value when the ramp-out probability is low; the forced commutation ratio corresponding to the departure probability of the different ramp is equal to zero. (2) When the flow of the system is in the saturated flow state, the continuous braking rate corresponding to the departure probability of the different ramp rises sharply, but the corresponding continuous brake rate value is higher than the corresponding continuous brake rate value when the ramp-out rate is high; At this time, the forced commutation ratio is also increased sharply, which increases with the increase of the ramp-out probability. The ramp-off probability is the same: (1) When the total flow of the system is in the free-flow state, the continuous brake corresponding to the different ramp-in vehicle probability increases gently, however, the influence of different ramp-on-vehicle probability on the continuous braking rate is not significant; The ratio of forced commutation corresponding to the probability of the ramp-in vehicle is equal to zero. (2) When the flow of the system is in the saturated flow state, the continuous braking rate corresponding to the vehicle probability of the different ramp rises sharply, and the continuous brake rate value corresponding to the ramp entrance rate is lower than the corresponding continuous brake rate value when the ramp-in ratio is high; At this time, the forced commutation ratio is also increased sharply, which increases with the increase of the ramp-in probability.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U491

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