MERLIN: Mesopically Enhanced Road Lighting: Improving Night-vision

该项目将研究如何改变住宅区道路的照明，以保持良好的视力，同时尽量减少能源消耗。在住宅道路上，道路照明主要是为了满足行人的需要而设计的。道路照明对行人的好处是增强安全运动（例如，增加潜在绊倒危险的可见度）和感知安全。最大限度地减少能源消耗还将降低运营成本和碳排放。英国的道路照明每年消耗2.5TWh电力，其中约三分之一与住宅街道有关（其余为干线照明、标志和护柱）。以0.10/kWh的典型单位成本计算，这意味着每年的成本超过8300万美元。照明技术和我们对中间视觉的理解的最新进展有可能改善照明的光谱功率分布（SPD）和空间分布的规范，以实现照明水平的降低，从而降低能耗，同时保持甚至提高效益水平。改善照明设计从而节约能源的一个直接途径是更好地规范住宅街道照明标准。这将通过修订英国标准BS 5489 -1来实现：其中两个申请人是国家和国际道路照明标准化组织的成员，因此能够实施这些修订。与国际惯例相比，英国使用的照明水平可能过高。在英国，住宅街道的平均路面照明度在2至15勒克斯的范围内。然而，澳大利亚倾向于使用仅0.5至0.85勒克斯的平均照度，日本倾向于使用3至5勒克斯的平均照度。因此，在英国减少光照水平是有明显潜力的。该项目包括三个主要阶段。首先，我们建议识别和识别行人在夜间的主要视觉任务，以及他们认为重要的视觉环境的关键方面。这将通过分析目前住宅区道路上的行人环境来确定：将进行眼动跟踪研究，以确定夜间行走时看到的物体，以及确定街道的空间和光度特征如何影响感知安全的保证研究。据我们所知，“对行人来说什么是重要的”这一基本问题并不是以往任何研究的重点。第二阶段的工作将确定这些关键的视觉任务是如何受到照明水平，光谱功率分布和照明空间分布的影响。这将在两项平行研究中进行检查;（i）阈值视觉反应的检查，以及（ii）应用任务（如面部识别）的性能检查。最后阶段将根据项目中获得的数据确定住宅街道照明设计的最佳标准，从而确定最佳照度和光源特性。随后，我们将使用该项目产生的优化设计标准重新照明住宅街道样本，向最终用户展示和验证实施新研究结果的好处。由于这项工作将取决于以前的调查结果，并由于它需要与地方当局达成协议，因此项目的这一部分被安排为后续活动。照明设备制造商已经同意捐赠这项工作所需的大部分设备。

This project will investigate how the lighting of roads in residential areas might be changed so as to preserve the benefits of good vision while minimising energy consumption. In residential roads the road lighting is designed primarily to meet the needs of pedestrians. Benefits of road lighting for the pedestrian are enhancement of safe movement (e.g. increased visibility of potential trip hazards) and perceived safety. Minimising energy consumption will also reduce operating costs and carbon emissions. Road lighting in the UK consumes 2.5TWh electricity per annum, of which approximately one third is associated with residential streets (the remainder being trunk route lighting, signs and bollards). At a typical unit cost of 0.10/kWh this represents an annual cost of over 83 million. Recent advances in lighting technology and in our understanding of mesopic vision have the potential to improve specification of the spectral power distribution (SPD) and spatial distribution of lighting to achieve reductions in the level of illumination, and hence a reduction in energy consumption, whilst maintaining or even improving the level of benefits. A direct route to improved lighting design and thus energy savings will be through better specification of residential street lighting criteria. This will be realised by amendments to British Standard BS5489-1: two of the applicants serve on national and international standardisation bodies for road lighting and so are able to implement such amendments.Comparison with international practise suggests that light levels used in the UK may be excessive. In the UK, residential streets are lit to average pavement illuminances in the range 2 to 15 lux. However, Australia tends to use average illuminances of only 0.5 to 0.85 lux, and 3 to 5 lux in Japan. Thus there is clear potential to reduce light levels in the UK.The project involves three major stages. First, we propose to identify and characterise the principal visual tasks of pedestrians at night-time and the key aspects of the visual environment they consider to be important. This will be established by analysing the pedestrian environment on current residential roads: an eye tracking study will be carried out to determine what objects are viewed when walking at night-time together with a reassurance study to determine how the spatial and photometric characteristics of streets affect perceived safety. To our knowledge, the fundamental question of 'What is important to pedestrians' has not been the focus of any previous research. The work proposed for the second stage will identify how these critical visual tasks are affected by the level of illumination, spectral power distribution and spatial distribution of lighting. This will be examined in two parallel studies; (i) an examination of threshold visual responses, and (ii) an examination of the performance of applied tasks, such as facial recognition. The final stage will determine the optimum criteria for lighting design in residential streets and hence the optimum illuminances and light source properties based on the data obtained in the project. We will subsequently demonstrate and validate the benefits of implementing the new findings to end users by re-lighting a sample of residential streets using the optimised design criteria that will emerge from this project. Because this work will be dependant upon the previous findings and because it requires agreement with local authorities this part of the project has been scheduled as a follow-up activity. Agreement has already been obtained from lighting equipment manufacturers to donate much of the equipment needed for this work.