Artificial Light at Night (ALAN) Research Literature Database -- Query Results

Scott, R. (1980). THE RELATIONSHIP BETWEEN ROAD LIGHTING QUALITY AND ACCIDENT FREQUENCY – TRRL LABORATORY REPORT 929. Abstract: many studies have related changes in accident frequency to the presence of street lighting, and a few have examined its variation over a range of lighting quality, as measured by illuminance. this investigation attempts to find which of several measures of lighting (describing quantity – as represented by luminance or illuminance – uniformity and glare) most clearly explain variations in accident frequency. about 100 lit sites, almost all in built-up areas, were measured for lighting quality in dry-road conditions. the lighting variables measured were related to the dark:day ratios of accident frequency for the same sites. the strongest relationship found was that for average road surface luminance: in the range 0.5-2.0 candelas/m2, it is estimated that an increase of 1 cd/m2 is associated with a 35 per cent lower accident ratio. other measures of luminance and illuminance were also found to be related to accident ratio (and to each other), but not as clearly as was average road luminance, which is therefore the preferred explanatory variable. analysis of pedestrian and non-pedestrian accidents separately did not reveal a relationship between the former and lighting quality. in contrast, non-pedestrian accidents showed similar relationships to those for all accidents, with the addition of a possible relationship with overall uniformity of luminance.(a) Keywords: Lighting; quality; accident rate; accident; frequency; luminance; glare; uniformity; urban area; daylight; darkness; surfacing; pedestrian http://alandb.darksky.org/show.php?record=647
Tan, M. (2016). Use of an inside buffer method to extract the extent of urban areas from DMSP/OLS night-time light data in North China. GIScience & Remote Sensing, 53(4), 444–458. Abstract: Defense Meteorological Satellite Program (DMSP)/Operational Linescan System (OLS) night-time imagery provides a valuable data source for mapping urban areas. However, the spatial extents of large cities are often over-estimated because of the effect of over-glow from night-time light if a fixed thresholding technique is used. In the work reported here, an inside buffer method was developed to solve this issue. The method is based on the fact that the area over-estimated is proportional to the extent of the lit area if a fixed threshold is used to extract urban areas in a region/county. Using this method, the extents of urban areas in North China were extracted and validated by interpretations from Landsat Thematic Mapper images. The results showed that the lit areas had a significant linear relationship with the urban areas for 120 representative cities in North China in 2000, with an R2 value of over 0.95. This demonstrates that the inside buffer method can be used to extract urban areas. The validation results showed that the inside buffer model developed in 2000 can be directly used to extract the extent of urban areas using more recent night-time light imagery. This is of great value for the timely updating of urban area databases in large regions or countries. Keywords: Remote Sensing; DMSP-OLS; OLS; DMSP; inside buffer model; China; over-glow; urban areas; urban; urbanism http://alandb.darksky.org/show.php?record=1352

Abstract: many studies have related changes in accident frequency to the presence of street lighting, and a few have examined its variation over a range of lighting quality, as measured by illuminance. this investigation attempts to find which of several measures of lighting (describing quantity – as represented by luminance or illuminance – uniformity and glare) most clearly explain variations in accident frequency. about 100 lit sites, almost all in built-up areas, were measured for lighting quality in dry-road conditions. the lighting variables measured were related to the dark:day ratios of accident frequency for the same sites. the strongest relationship found was that for average road surface luminance: in the range 0.5-2.0 candelas/m2, it is estimated that an increase of 1 cd/m2 is associated with a 35 per cent lower accident ratio. other measures of luminance and illuminance were also found to be related to accident ratio (and to each other), but not as clearly as was average road luminance, which is therefore the preferred explanatory variable. analysis of pedestrian and non-pedestrian accidents separately did not reveal a relationship between the former and lighting quality. in contrast, non-pedestrian accidents showed similar relationships to those for all accidents, with the addition of a possible relationship with overall uniformity of luminance.(a)

Keywords: Lighting; quality; accident rate; accident; frequency; luminance; glare; uniformity; urban area; daylight; darkness; surfacing; pedestrian

http://alandb.darksky.org/show.php?record=647

Abstract: Defense Meteorological Satellite Program (DMSP)/Operational Linescan System (OLS) night-time imagery provides a valuable data source for mapping urban areas. However, the spatial extents of large cities are often over-estimated because of the effect of over-glow from night-time light if a fixed thresholding technique is used. In the work reported here, an inside buffer method was developed to solve this issue. The method is based on the fact that the area over-estimated is proportional to the extent of the lit area if a fixed threshold is used to extract urban areas in a region/county. Using this method, the extents of urban areas in North China were extracted and validated by interpretations from Landsat Thematic Mapper images. The results showed that the lit areas had a significant linear relationship with the urban areas for 120 representative cities in North China in 2000, with an R2 value of over 0.95. This demonstrates that the inside buffer method can be used to extract urban areas. The validation results showed that the inside buffer model developed in 2000 can be directly used to extract the extent of urban areas using more recent night-time light imagery. This is of great value for the timely updating of urban area databases in large regions or countries.