Assessing Disability Glare Potential of Reflections from New Construction

Abstract

Disability glare, or visual impairment due to extreme brightness or contrast, can be caused by intense reflections from new constructions onto existing transportation or building infrastructure located nearby. A case study analyzed a disability glare hazard at an airport created by the installation of a large array of photovoltaic panels between an air traffic control tower and the aircraft taxiway. The panels reflected blinding quantities of daylight into the control tower, produced temporary afterimages, and dangerously obscured taxiing aircraft. The existing FAA guidelines for installation of solar technologies are discussed relative to their shortcomings in identifying the glare hazard. High dynamic range photography was used to analyze the glaring situation at the airport. The authors proposed a maximum brightness threshold of 30,000 cd/m2 based on the physiology of human vision and the brightness of tasks necessary for air traffic controllers at the case study airport. Detailed reflectivity and three-dimensional models of the photovoltaic panels and the airport were created and validated against measured data. These models were used to perform an annual analysis of the glare hazard. This analysis is displayed temporally by graphs and spatially by images that indicate where the glaring reflections originate. Such information is useful in identifying potential for disability glare before new constructions are built. Finally, the authors used the new method to analyze designs for remediation of the glare hazard.