Development of an Illuminated Delineator using in Laser Beams

轮廓有助于引导驾驶员沿着道路行驶，特别是在夜间或恶劣的天气条件下。在浓雾中，轮廓标的足够能见度对于向驾驶员提供道路几何形状提示非常重要。本文提出了一种新的照明轮廓，采用激光束。关于激光束在雾中的可见性的数据很少。然而，由于激光束的高强度、高能量和单斜且强的方向性，可以预期激光束在浓雾中高度可见。本研究是为了评估激光束在雾中的能见度。实验在日本筑波市公共工程研究所交通标志实验室进行。该实验室配备了一个能够产生人工雾的观察室。观测室的尺寸为：长30米，宽10米，高10米。研究了两种类型的激光头和包含两个10 W辉光灯的照明轮廓标的有效性。因变量是激光束上特定点的亮度和估计亮度。主要自变量为雾密度和观测室内照度。激光束在浓雾中被观察为尖锐的光线。如Prichard和Blackwell [3]所指出的，激光束在雾中的可见度与正常光的可见度呈反比关系。此外，受试者报告说，激光束的方向性可以有效地指示高速公路的方向。然而，激光束的可见性受到观察室照度的强烈影响，必须注意防止驾驶员直视多余的激光束[7]。根据目前的研究结果，我们得出结论，激光束可能是有用的照明光源在浓雾中，如果这个安全问题可以克服。

Delineation helps to guide drivers along roadways, particularly at night or in adverse weather conditions. In dense fog, adequate visibility of the delineator is important for providing the driver with road geometry cues. The present paper proposes a new illuminated delineator that employs laser beams. Very little data has been published with regard to the visibility of laser beams in fog. However, laser beams can be expected to be highly visible in dense fog due to their high intensity, high energy, and directivity that is both monoclinic and strong. The present study was conducted in order to evaluate the visibility of laser beams in fog. The experiment was conducted in the Traffic Sign Laboratory, Public Works Research Institute, in Tsukuba, Japan. The laboratory is equipped with an observation room capable of generating artificial fog. The dimensions of the observation room are : length, 30m ; width, 10m ; and height, 10m. The effectiveness of two types of laser heads and an illuminated delineator containing two 10 W glow lamps was investigated. The dependent variables were luminance at a specific point on the laser beam and estimated brightness. The major independent variables were fog density and illuminance in the observation room. The laser beams were observed as sharp lines of light in dense fog. The visibility of the laser beams in fog had an inverse relationship to that of normal light, as indicated by Prichard and Blackwell [3]. In addition, subjects reported that the directivity of the laser beams could effectively indicate the direction of the highway. However, the visibility of the laser beams was strongly affected by the illuminance in the observation room, and care must be taken in order to prevent drivers from looking directly at redundant laser beams [7]. Based on the results of the present study, we conclude that laser beams may be useful lighting sources in dense fog if this safety problem can be overcome.