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Author Kersavage, K.; Skinner, N.P.; Bullough, J.D.; Garvey, P.M.; Donnell, E.T.; Rea, M.S.
Title Investigation of flashing and intensity characteristics for vehicle-mounted warning beacons Type Journal Article
Year 2018 Publication Accident Analysis & Prevention Abbreviated Journal Accident Analysis & Prevention
Volume 119 Issue Pages 23-28
Keywords Security; Public Safety; Lighting
Abstract Reducing the potential for crashes involving front line service workers and passing vehicles is important for increasing worker safety in work zones and similar locations. Flashing yellow warning beacons are often used to protect, delineate, and provide visual information to drivers within and approaching work zones. A nighttime field study using simulated workers, with and without reflective vests, present outside trucks was conducted to evaluate the effects of different warning beacon intensities and flash frequencies. Interactions between intensity and flash frequency were also analyzed. This study determined that intensitiesof 25/2.5 cd and 150/15 cd (peak/trough intensity) provided the farthest detection distances of the simulated worker. Mean detection distances in response to a flash frequency of 1 Hz were not statistically different from those in response to 4 Hz flashing. Simulated workers wearing reflective vests were seen the farthest distances away from the trucks for all combinations of intensity and flash frequency.
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Series Editor Series Title Abbreviated Series Title
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ISSN 0001-4575 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) GFZ @ kyba @ Serial 1950
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Author Schuler, L.D.; Schatz, R.; Berweger, C.D.
Title From global radiance to an increased local political awareness of light pollution Type Journal Article
Year 2018 Publication Environmental Science & Policy Abbreviated Journal Environmental Science & Policy
Volume 89 Issue Pages 142-152
Keywords Remote Sensing; Public Safety; Animals
Abstract We present a novel transparent method to analyze measurements of the Suomi NPP (Suomi National Polar-orbiting Partnership) satellite in night vision, into luminous intensity and luminance on the community level, with a special focus to address light planners and non-experts, and for the first time, to further address politicians, decision-makers and law-makers, and governmental agencies. We checked the propagated efficiency of road lighting and its impact on luminous flux, and identified a waste of light emissions in the largest city of Switzerland, Zurich. We looked at security (issues like criminal acts) and found no correlation with communities’ luminous intensity. We assessed road safety (accidents) against local luminance and found no evidence of darkness being more risky when the overall distribution of illuminance on roads is considered. We screened crayfish habitats in the Canton of Zurich against local illuminance and found clear evidence of preferred darkness for the living. Based on this finding, we propose an upper limit for light immissions in the crayfish habitats. These four analyses have been chosen to demonstrate the usefulness of Suomi NPP's coverage in combination with our approach. We could apply it to ecological, social and economical topics. We hope others will follow and we can draw more attention of governments to take action to reduce the light pollution on local levels, like Langnau am Albis of Switzerland has exemplified.
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ISSN 1462-9011 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) GFZ @ kyba @ Serial 1965
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Author Sullivan, J.M.; Flannagan, M.J.
Title The role of ambient light level in fatal crashes: inferences from daylight saving time transitions Type Journal Article
Year 2002 Publication Accident Analysis & Prevention Abbreviated Journal Accident Analysis & Prevention
Volume 34 Issue 4 Pages 487-498
Keywords Public Safety; Lighting
Abstract The purpose of this study was to estimate the size of the influence of ambient light level on fatal pedestrian and vehicle crashes in three scenarios. The scenarios were: fatal pedestrian crashes at intersections, fatal pedestrian crashes on dark rural roads, and fatal single-vehicle run-off-road crashes on dark, curved roads. Each scenario's sensitivity to light level was evaluated by comparing the number of fatal crashes across changes to and from daylight saving time, within daily time periods in which an abrupt change in light level occurs relative to official clock time. The analyses included 11 years of fatal crashes in the United States, between 1987 and 1997. Scenarios involving pedestrians were most sensitive to light level, in some cases showing up to seven times more risk at night over daytime. In contrast, single-vehicle run-off-road crashes showed little difference between light and dark time periods, suggesting factors other than light level play the dominant role in these crashes. These results are discussed in the context of the possible safety improvements offered by new developments in adaptive vehicle headlighting.
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ISSN 0001-4575 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) GFZ @ kyba @ Serial 2126
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Author Flannagan, M.J.; Sivak, M.; Traube, E.C.; Kojima, S.
Title Effects of Overall Low-Beam Intensity on Seeing Distance in the Presence of Glare Type Journal Article
Year 2000 Publication Transportation Human Factors Abbreviated Journal Transportation Human Factors
Volume 2 Issue 4 Pages 313-330
Keywords Public Safety; Vision
Abstract Previous studies have demonstrated that current low-beam headlamps do not provide adequate seeing distance for safety. Could this situation be improved by providing more total light from low-beam headlamps, leaving the relative distribution of light unchanged? Although such a proposal is probably not the best practical solution, it is important to consider some of the visual consequences of a general increase in light to analyze the overall problem of low-beam headlighting.

In a nighttime field study we measured seeing distance in the presence of glare as a function of headlamp intensity, always varying the intensity of the seeing light and glare light by the same proportion. Increasing intensity by a factor of about 3.8 increased seeing distance by about 17% for both young and old drivers. This result is consistent with predictions from quantitative vision modeling using veiling luminance to represent the disabling effects of glare. We also collected subjective estimates of discomfort glare and found, as expected, that the higher intensities produced substantially more discomfort.

Our findings suggest that, if objective visual performance is the only criterion, there is no clear upper limit to how intense low-beam headlamps should be. However, there may be a level at which people simply will not tolerate the subjectively discomforting effects of glare, or at which glare indirectly affects objective performance through its effects on subjective comfort. Because subjective discomfort, rather than objective visual performance, may be the limiting consideration for setting maximum glare levels, more research should be done to understand the nature and consequences of discomfort glare, including possible effects of subjective comfort on objective visual behavior.
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ISSN 1093-9741 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) GFZ @ kyba @ Serial 2127
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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 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
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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 (up) GFZ @ kyba @ Serial 2160
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