Traffic accidents frequently occur at the nose of highway exit ramps for a variety of reasons. When attempting to take an exit, a driver’s line of sight may be obscured by the curvature or slope of the main expressway, roadside vegetation, traffic signs, and other vehicles traveling alongside. These increase the likelihood of accidents due to inaccurate or poor driver judgement when approaching a highway exit. Because of emotional responses that accompany the possibility of missing an exit, many drivers act irrationally through haphazard acceleration or braking, aggressive lane changes; in some cases, even coming to a complete stop and reversing against the flow of high speed traffic to correct their course. This study applies to curved highway exit corridors with a poor line of sight. The total visible area of the exit ramp is defined in accordance with the design specifications of both the highway routes and exit ramps, which was then further refined by considering the driving characteristics of both the drivers and of surrounding traffic. This study set out to establish a reliable occlusion model of highway exits with the following goals in mind. Geometric equations describing the area and volume of the target area of the exit ramp are established. Discrete expression equation was deployed to establish the occlusion model for the target area within the visual field. Parameters taken from specifications of the Hunan section of the Shanghai-Kunming Expressway are used for multiple calculations, in which obstruction patterns of objects with the same width, and objects with different width at different positions are analyzed. Based on the patterns observed from stimulated experiments mentioned above, multiple effective measures were proposed to prevent the obstruction of the highway exit ramp. In summary, this study provides theoretical support for prevention of obstruction as well as an anti-occlusion model for better identification of the highway exit ramps by intelligent vehicle systems.

由于各种原因，交通事故经常发生在高速公路出口匝道的前端。尝试退出时，驾驶员的视线可能会被主要高速公路的曲率或坡度，路边的植被，交通标志以及其他在旁边行驶的车辆所遮挡。当驶入高速公路出口时，由于驾驶员的判断不正确或不正确，这些会增加发生事故的可能性。由于可能会错过出口而引起的情绪反应，许多驾驶员通过随意的加速或制动，激进的车道改变而采取不合理的行动；在某些情况下，甚至会完全停止并逆转高速交通流以纠正路线。这项研究适用于视线不佳的弯曲高速公路出口走廊。出口坡道的总可见面积是根据公路路线和出口坡道的设计规范定义的，然后通过考虑驾驶员和周围交通的行驶特性进一步完善。这项研究着眼于以下目标，着手建立可靠的高速公路出口阻塞模型。建立描述出口坡道目标区域的面积和体积的几何方程。部署离散表达方程以建立视野内目标区域的遮挡模型。沪昆高速公路湖南段规格取的参数进行多次计算，分析宽度相同，宽度不同的物体在不同位置的遮挡方式。根据上述受激实验观察到的模式，提出了多种有效措施来防止高速公路出口匝道的阻塞。总而言之，这项研究为防止障碍物提供了理论支持，并为智能车辆系统更好地识别高速公路出口匝道提供了一种反遮挡模型。