考虑道路信息和转向灯的可换道BML模型
A LANE-CHANGING BML MODEL CONSIDERING THE INFLUENCE OF BOTH LANE INFORMATION AND TURN SIGNALS
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摘要: 车辆换道是司机为获得更好行驶条件而采用的常见措施, 而转向灯对车辆换道行为有重要的指导作用. 本文在BML (Biham-Middleton-Levine)模型的基础上加以改进, 提出了综合考虑道路信息和前车转向灯影响的可换道BML模型. 当车辆无法前行时, 如满足换道条件, 则将道路信息(车道密度及平均速度)和转向灯影响量化为车辆换道概率, 确定车辆是否可以换道. 通过数值模拟, 研究了周期边界条件下车辆换道行为对有、无交通灯控制的两种BML模型发生相变的临界密度以及系统通行能力的影响. 模拟结果表明对于无交通灯BML模型, 引入换道规则可以明显提高系统发生相变的临界密度, 在较小尺度下该临界密度接近有交通灯BML模型, 换道效果明显, 并发现了一种新的局部拥堵和自由流的共存相, 讨论了该共存相的生成和演化机制. 在较高密度下局部阻塞将演化为全局拥堵; 对于有交通灯BML模型, 引入换道规则对系统发生相变的临界密度没有明显的影响, 但相变的过渡区域更窄. 这表明有交通灯时, 换道虽然可以改变局部交通特征, 但难以显著影响交通系统的全局特征.Abstract: The lane-changing behaviors of vehicles are frequently adopted by drivers in order to get better driving conditions and turn signal plays an essential role in guiding vehicles' lane-changing behaviors. In this paper, based on the BML (Biham-Middleton-Levine model ) model, we proposed a lane- changing cellular automata model which takes the influence of both lane information and turn signals into account. When a vehicle cannot move forward, the driver will judge whether the vehicle meets the lane-changing conditions or not. If the driver can change his/her lane, then the lane-changing probability is calculated according to the lane information (such as average velocities and densities of those vehicles in his own and target lanes) and the state of turn signals. Finally, the driver can determine whether he/she changes lane or not by the corresponding probability. Numerical simulations were carried out to investigate the effect of lane-changing behaviors on the phase transition between the free flow phase and the global jamming phase. Two kinds of BML models were studied, one with traffic lights and the other without traffic lights. Numerical results show that the critical density of the BML model without traffic lights increases considerably due to the introduction of lane-changing rules. At a smaller scale, the critical density approximates that of the BML model with traffic light control. The effect of lane change is significant on traffic dynamics. Furthermore, a new coexisting phase of both the free flow phase and the local jamming phase was found. The underlying generation and evolution mechanism of the coexisting phase is discussed in detail. It is shown that the local congestions will result in the global congestion under higher densities. However, the lane-changing rules does not have distinct effect on the critical density of the BML model with traffic lights. But the region of phase transition becomes narrower. It indicates that lane-changing behaviors can lead to variations of local traffic features and take less effect on the global features of traffic system.