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Author Wood, J.M.; Isoardi, G.; Black, A.; Cowling, I.
Title Night-time driving visibility associated with LED streetlight dimming Type Journal Article
Year 2018 Publication Accident; Analysis and Prevention Abbreviated Journal Accid Anal Prev
Volume 121 Issue Pages (down) 295-300
Keywords Public Safety
Abstract New LED streetlighting designs and dimming are being introduced worldwide, however, while their cost savings are well established, their impact on driving performance has received little attention. This study investigated the effect of streetlight dimming on night-time driving performance. Participants included 14 licensed drivers (mean age 34.2 +/- 4.9 years, range 27-40 years) who drove an instrumented vehicle around a closed circuit at night. Six LED streetlights were positioned along a 250 m, straight section and their light output varied between laps (dimming levels of 25%, 50%, 75% and 100% of maximum output; L25, L50, L75 and L100 respectively; at 100% average road surface luminance of 1.14 cd/m(2)). Driving tasks involved recognition distances and reaction times to a low contrast, moving target and a pedestrian walking at the roadside. Participants drove at an average driving speed of 55 km/hr in the streetlight zone. Streetlight dimming significantly delayed driver reaction times to the moving target (F3,13.06 = 6.404; p = 0.007); with an average 0.4 s delay in reaction times under L25 compared to L100, (estimated reduction in recognition distances of 6 m). Pedestrian recognition distances were significantly shorter under dimmed streetlight levels (F3,12.75 = 8.27; p = 0.003); average pedestrian recognition distances were 15 m shorter under L25 compared to L100, and 11 m shorter under L50 compared to L100. These data suggest that streetlight dimming impacts on driver visibility but it is unclear how these differences impact on safety; future studies are required to inform decisions on safe dimming levels for road networks.
Address School of Chemistry, Physics and Mechanical Engineering, Faculty of Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0001-4575 ISBN Medium
Area Expedition Conference
Notes PMID:30317014 Approved no
Call Number GFZ @ kyba @ Serial 2160
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Author Cai, W.; Yue, J.; Dai, Q.; Hao, L.; Lin, Y.; Shi, W.; Huang, Y.; Wei, M.
Title The impact of room surface reflectance on corneal illuminance and rule-of-thumb equations for circadian lighting design Type Journal Article
Year 2018 Publication Building and Environment Abbreviated Journal Building and Environment
Volume 141 Issue Pages (down) 288-297
Keywords Lighting
Abstract Recently, corneal illuminance attracts much attention because it is closely related to important functions of indoor lighting. Especially, applying circadian light in the built environment places a challenging requirement on indirect corneal illuminance. In this work, rule-of-thumb equations are proposed to guide circadian lighting design: (i) for artificial lighting, Ecor,avg (i) = (Φ/C1) · ρ/(1−ρ′), where Ecor,avg (i) is the average indirect corneal illuminance at standing or sitting positions, Φ is the initial flux from luminaires, C1 is a constant comparable to the total room surface area, ρ is the reflectance of the surface where the first reflection occurs, and ρ′ is the area-weighted average of surface reflectance; and (ii) for daylighting, Ecor,avg (i) = C2 · WWR · ρ/(1−ρ′), where C2 is a constant, and WWR represents the window-to-wall ratio.

The equations above are validated by comparing against numerical simulation data obtained with the Radiance software. For artificial lighting simulation, various combinations of room surface reflectance, initial light distribution, and WWR are investigated; and for daylighting simulation, different combinations of surface reflectance, WWR, and geographic location are analyzed. The good fits to simulation data indicate that the proposed simple equations can provide reasonably accurate results for quick feedback at the field. It is also demonstrated that room surface reflectance has a dominant impact on indirect corneal illuminance. The approach of improving surface reflectance is more favorable than increasing luminaire flux or expanding window area, and therefore should be the recommended approach to achieve quality and efficient circadian lighting.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0360-1323 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1929
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Author Jones, B.A.
Title Spillover health effects of energy efficiency investments: Quasi-experimental evidence from the Los Angeles LED streetlight program Type Journal Article
Year 2018 Publication Journal of Environmental Economics and Management Abbreviated Journal Journal of Environmental Economics and Management
Volume 88 Issue Pages (down) 283-299
Keywords Human Health; LED; public health; outdoor lighting; Los Angeles; economics; energy efficiency; breast cancer; fossil fuel carbon emissions
Abstract Payback estimates of energy efficiency investments often ignore public health externalities. This is problematic in cases where spillover health effects are substantial, such as when the application of new technology alters environmental exposures. When health externalities are included in return on investment calculations, energy efficiency programs may look more or less attractive than suggested by conventional “energy savings only” estimates. This analysis exploits the quasi-experiment provided by the 2009 Los Angeles (LA) LED streetlight efficiency program to investigate the returns on investments inclusive of an originally estimated health externality. Using the synthetic control method, we find that the LED streetlight program is associated with a lagged increase in breast cancer mortality of 0.479 per 100,000. Inclusive of the effects of LEDs on breast cancer and avoided carbon emissions, the LA LED program provides a −146.2% 10-year return compared to +118.2% when health outcomes and carbon emissions are ignored.
Address Department of Economics, University of New Mexico, 1 UNM Drive, MSC 05 3060, Albuquerque, NM, 87131, USA; bajones(at)unm.edu
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0095-0696 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1976
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Author Hänel, A.; Posch, T.; Ribas, S.J.; Aubé, M.; Duriscoe, D.; Jechow, A.; Kollath, Z.; Lolkema, D.E.; Moore, C.; Schmidt, N.; Spoelstra, H.; Wuchterl, G.; Kyba, C.C.M.
Title Measuring night sky brightness: methods and challenges Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal Journal of Quantitative Spectroscopy and Radiative Transfer
Volume 205 Issue Pages (down) 278-290
Keywords skyglow
Abstract Measuring the brightness of the night sky has become an increasingly important topic in recent years, as artificial lights and their scattering by the Earthâ??s atmosphere continue spreading around the globe. Several instruments and techniques have been developed for this task. We give an overview of these, and discuss their strengths and limitations. The different quantities that can and should be derived when measuring the night sky brightness are discussed, as well as the procedures that have been and still need to be defined in this context. We conclude that in many situations, calibrated consumer digital cameras with fisheye lenses provide the best relation between ease-of-use and wealth of obtainable information on the night sky. While they do not obtain full spectral information, they are able to sample the complete sky in a period of minutes, with colour information in three bands. This is important, as given the current global changes in lamp spectra, changes in sky radiance observed only with single band devices may lead to incorrect conclusions regarding long term changes in sky brightness. The acquisition of all-sky information is desirable, as zenith-only information does not provide an adequate characterization of a site. Nevertheless, zenith-only single-band one-channel devices such as the â??Sky Quality Meterâ? continue to be a viable option for long-term studies of night sky brightness and for studies conducted from a moving platform. Accurate interpretation of such data requires some understanding of the colour composition of the sky light. We recommend supplementing long-term time series derived with such devices with periodic all-sky sampling by a calibrated camera system and calibrated luxmeters or luminance meters.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1731
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Author Li, K.; Chen, Y.
Title A Genetic Algorithm-Based Urban Cluster Automatic Threshold Method by Combining VIIRS DNB, NDVI, and NDBI to Monitor Urbanization Type Journal Article
Year 2018 Publication Remote Sensing Abbreviated Journal Remote Sensing
Volume 10 Issue 2 Pages (down) 277
Keywords Remote Sensing
Abstract Accurate and timely information related to quantitative descriptions and spatial distributions of urban areas is crucial to understand urbanization dynamics and is also helpful to address environmental issues associated with rapid urban land-cover changes. Thresholding is acknowledged as the most popular and practical way to extract urban information from nighttime lights. However, the difficulty of determining optimal threshold remains challenging to applications of this method. In order to address the problem of selecting thresholds, a Genetic Algorithm-based urban cluster automatic threshold (GA-UCAT) method by combining Visible-Infrared Imager-Radiometer Suite Day/Night band (VIIRS DNB), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-up Index (NDBI) is proposed to distinguish urban areas from dark rural background in NTL images. The key point of this proposed method is to design an appropriate fitness function of GA by means of integrating between-class variance and inter-class variance with all these three data sources to determine optimal thresholds. In accuracy assessments by comparing with ground truth—Landsat 8 OLI images, this new method has been validated and results with OA (Overall Accuracy) ranging from 0.854 to 0.913 and Kappa ranging from 0.699 to 0.722 show that the GA-UCAT approach is capable of describing spatial distributions and giving detailed information of urban extents. Additionally, there is discussion on different classifications of rural residential spots in Landsat remote sensing images and nighttime light (NTL) and evaluations of spatial-temporal development patterns of five selected Chinese urban clusters from 2012 to 2017 on utilizing this proposed method. The new method shows great potential to map global urban information in a simple and accurate way and to help address urban environmental issues.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2072-4292 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2340
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