scholarly journals Roadway Lighting’s Effect on Pedestrian Safety at Intersection and Midblock Crosswalks

2021 ◽  
Author(s):  
Rajaram Bhagavathula ◽  
◽  
Ronald Gibbons ◽  
Andrew Kassing ◽  
◽  
...  
Keyword(s):  
Pedestrian Detection ◽  
Positive Contrast ◽  
Pedestrian Safety ◽  
Light Level ◽  
Lighting Design ◽  
Visual Performance ◽  
Light Levels ◽  
Disability Glare ◽  
Safety Countermeasures ◽  
Pedestrian Crossing

This study evaluates the visual performance of four intersection lighting designs and five midblock crosswalk lighting designs along with two pedestrian safety countermeasures (rectangular rapid flashing beacons and flashing signs) at three light levels. The study involved a pedestrian detection task, which was completed at night on a realistic roadway intersection and a midblock crosswalk. The results from the study showed that driver nighttime visual performance at intersection and midblock crosswalks was influenced by the lighting design and light level. Intersections should be illuminated to an average horizontal illuminance of 14 lux (1.3 fc). This light level ensures optimal visibility of pedestrians regardless of the lighting design (or luminaire layout) of the intersection. The average horizontal illuminance of 14 lux (1.3 fc) also increases the visibility of pedestrians when glare from oncoming vehicles is present. The 14 lux (1.3 fc) average horizontal illuminance is valid for all lighting designs evaluated except the lighting design that illuminated the exits of the intersection. When the exits of the intersection are illuminated, an average horizontal illuminance of 24 lux (2.2 fc) is needed to offset the disability glare from opposing vehicles. Midblock crosswalks should be illuminated to an average vertical illuminance of 10 lux (0.9 fc) to ensure optimal pedestrian visibility. Where overhead lighting is available, midblock crosswalk lighting designs that render the pedestrian in positive contrast are recommended. Where overhead lighting is not available, crosswalk illuminators can be used to illuminate midblock crosswalks. At night, pedestrian crossing treatments such as rectangular rapid flashing beacons and flashing signs should not be used for pedestrian visibility at midblock crosswalks. Pedestrians crossing treatments should be used in conjunction with overhead lighting or crosswalk illuminators at the established vertical illuminance to ensure optimal pedestrian visibility at midblock crosswalks.

Comparisons between off-axis detection and on-axis recognition to implement mesopic photometry in roadway lighting standards

2019 ◽  
Vol 52 (4) ◽  
pp. 540-553
Author(s):  
R Ohashi ◽  
Y Akashi ◽  
T Uchida
Keyword(s):  
Peripheral Vision ◽  
Luminance Contrast ◽  
Light Level ◽  
Negative Influence ◽  
Visual Performance ◽  
Light Sources ◽  
Foveal Vision ◽  
Road Lighting ◽  
Light Levels ◽  
Roadway Lighting

Mesopic photometry can be applied to road lighting practice to enhance peripheral visual performance and to reduce light levels. However, mesopic photometry characterizes peripheral vision, whereas photopic photometry characterizes foveal vision at all light levels. Higher scotopic / photopic ( S/ P) ratio light sources which enhance peripheral visual performance may have a negative influence on foveal vision. In addition, light level reductions, as realized in British Standard 5489-1: 2013, may impair foveal visual performance. To investigate the above-described concern, we conducted two experiments. First, we investigated whether Landolt ring targets detected by peripheral vision can be recognized correctly after moving the line of sight to fixate on the targets in foveal vision. Then, we found that subjects could recognize in foveal vision almost all targets that peripheral vision detected. The S/ P ratio of the background lighting did not influence this tendency. Second, we investigated luminance contrast thresholds for foveal vision to compare them with those for peripheral vision, obtained from the first experiment. We found that threshold contrasts of targets recognized by foveal vision were lower than those detected by peripheral vision. These results lead to the conclusion that the use of higher S/ P ratio light sources has no negative influence for foveal vision when implementing mesopic photometry.

Change of color appearance due to extremely high light level: corresponding colors under 100 and 3000 cd/m2

2019 ◽  
Vol 2019 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Wenyu Bao ◽  
Minchen Wei
Keyword(s):  
Light Level ◽  
Limited Range ◽  
High Light ◽  
Color Preference ◽  
Color Appearance ◽  
Appearance Model ◽  
Color Matching ◽  
Light Levels ◽  
Appearance Models ◽  
Psychophysical Study

Great efforts have been made to develop color appearance models to predict color appearance of stimuli under various viewing conditions. CIECAM02, the most widely used color appearance model, and many other color appearance models were all developed based on corresponding color datasets, including LUTCHI data. Though the effect of adapting light level on color appearance, which is known as "Hunt Effect", is well known, most of the corresponding color datasets were collected within a limited range of light levels (i.e., below 700 cd/m2), which was much lower than that under daylight. A recent study investigating color preference of an artwork under various light levels from 20 to 15000 lx suggested that the existing color appearance models may not accurately characterize the color appearance of stimuli under extremely high light levels, based on the assumption that the same preference judgements were due to the same color appearance. This article reports a psychophysical study, which was designed to directly collect corresponding colors under two light levels— 100 and 3000 cd/m2 (i.e., ≈ 314 and 9420 lx). Human observers completed haploscopic color matching for four color stimuli (i.e., red, green, blue, and yellow) under the two light levels at 2700 or 6500 K. Though the Hunt Effect was supported by the results, CIECAM02 was found to have large errors under the extremely high light levels, especially when the CCT was low.

Light or presence of host trees: which is more important for the strangler fig?

1999 ◽  
Vol 15 (5) ◽  
pp. 589-602 ◽  
Author(s):  
Vidya R. Athreya
Keyword(s):  
Host Species ◽  
National Park ◽  
Canopy Cover ◽  
Light Level ◽  
Southern India ◽  
Evergreen Forest ◽  
Primary Forest ◽  
Light Levels ◽  
Host Trees ◽  
Main Host

Strangler fig density varied considerably in the evergreen forest of Karian Shola National Park, southern India, with 11 individuals ha−1 in an open trail area and 5.6 individuals ha−1 within the primary forest area. The index of light level was assessed by estimating the percentage of upper canopy cover along the longitudinal centre of ten, 500-m × 20-m plots in each of the two areas of the evergreen forest. However, the increase in strangler fig density was not correlated to light levels but was significantly correlated to the numbers of their main host species in the two areas. In Karian Shola National Park, strangler figs occurred predominantly on a few host species with 20 and 50% of strangler figs growing on Vitex altissima, Diospyros bourdilloni and Eugenia/Syzygium spp. in the primary forest and trail areas respectively. Both young and established strangler figs were recorded mainly on larger individuals of their host trees indicating that older host trees are likely to be more suitable for the germination and establishment of strangler figs. The reason for the above could be the higher incidence of humus-filled and decaying regions in the older host trees which would provide an assured supply of nutrients for the establishing strangler fig.

Macular Pigment and Visual Performance in Glare: Benefits for Photostress Recovery, Disability Glare, and Visual Discomfort

2011 ◽  
Vol 52 (10) ◽  
pp. 7406 ◽  
Author(s):  
James M. Stringham ◽  
Paul V. Garcia ◽  
Peter A. Smith ◽  
Leon N. McLin ◽  
Brian K. Foutch
Keyword(s):  
Macular Pigment ◽  
Visual Performance ◽  
Visual Discomfort ◽  
Disability Glare

scholarly journals Energy Efficient Lighting Design Criteria: Cost-Effective Solutions in an Industrial Environment

2007 ◽  
Author(s):  
Frank J. Agraz ◽  
John Maneri
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Return On Investment ◽  
Energy Savings ◽  
Cost Effective ◽  
Lighting Design ◽  
Design Criteria ◽  
Lighting System ◽  
Light Levels

The continual rising cost of energy, existing outdated lighting technology, and inefficient lighting designs have given property owners the opportunity to improve their facilities by retrofitting their existing luminaires with an energy efficient lighting system. A lighting retrofit uses the existing electrical infrastructure to replace, relocate, or convert existing luminaires with the latest generation of cost-effective components. New lighting technology has emerged within the last 6 years that generates energy savings of 40% to 50% while maintaining existing light levels. These upgraded and field-tested solutions lower energy consumption, generate a healthy financial return on investment, and can improve both the quality and quantity of light in the task area. As with any other solution, a cost-effective lighting system must be designed and engineered carefully to accommodate the needs of each work space. Simply installing a new lamp into an existing luminaire will not necessarily guarantee substantial energy savings or an improved lighting environment. In any space that uses electric lighting, the lighting designer must evaluate potential solutions for energy consumption, maintenance concerns, delivered light levels, hostile environments, and the overall economic impact of installing and long-term operation of the new system. In this paper, the author will discuss energy efficient lighting design criteria and how a lighting designer properly engineers a retrofit project to deliver energy savings without sacrificing light levels. The discussion includes a summary of both traditional and emerging technologies, and the long-term impact on energy consumption, maintenance, return on investment, lighting quality, and delivered light levels. Paper published with permission.

scholarly journals An approach to energy efficient lighting design for economic residential flats

2021 ◽  
Vol 850 (1) ◽  
pp. 012013
Author(s):  
Subhasish Das ◽  
Anubrata Mondal ◽  
Kamalika Ghosh
Keyword(s):  
Power Consumption ◽  
Energy Saving ◽  
Energy Efficient ◽  
Residential Building ◽  
Light Level ◽  
Lighting Design ◽  
Wide Range ◽  
Standard Values ◽  
Lighting Systems

Abstract The lighting design in a residential building now-a-days is not only limited to general lighting but also it is focused to provide quality lighting with the help of wide range of available luminaire with different orientations as well as colours with efficient use of energy, that opens up accurate characteristics of specific areas in any room of the building. The affordable housings in many states are some of the examples of residential building where most of the flats in a typical floor are using conventional lighting systems which are not energy efficient and light level is low compared to standards. This paper is mainly focused to provide a budget friendly as well as energy efficient lighting design with the help of new and energy efficient lamps using DIALux Software, which can be proposed to renovate the existing conventional lighting systems. In this paper effort has been made to reduce the power consumption in all rooms and lux levels has been achieved as per standard values along with good amount of energy saving with the use of newer technologies.

scholarly journals Interactive effects of temperature and light on reattachment success in the brown alga Fucus radicans

2019 ◽  
Vol 62 (1) ◽  
pp. 43-50
Author(s):  
Ellen Schagerström ◽  
Tiina Salo
Keyword(s):  
High Temperature ◽  
Water Temperature ◽  
Asexual Reproduction ◽  
Net Primary Production ◽  
Light Level ◽  
Interactive Effects ◽  
Low Light ◽  
Dispersal Capacity ◽  
Light Levels ◽  
The Baltic

Abstract Fucus radicans is an endemic habitat-forming brown macroalga in the Baltic Sea that commonly complements its sexual reproduction with asexual reproduction. Asexual reproduction in F. radicans takes place through formation of adventitious branches (hereafter fragments), but the exact mechanisms behind it remain unknown. We assessed experimentally the importance of two environmental factors determining the re-attachment success of F. radicans fragments. By combining different light conditions (daylength and irradiance; high or low light) and water temperature (+14°C and +4°C), we mimicked ambient light and temperature conditions of winter, spring/autumn and summer for F. radicans. Fragments were able to re-attach in all tested conditions. Temperature and light had an interactive impact on re-attachment: the combination of high temperature and high light level resulted in the highest re-attachment success, while light level had no effects on re-attachment success in cooler water temperature and the re-attachment success in high temperature under low light levels was very low. The results suggest that rhizoid formation, and thus re-attachment success, may depend on the net primary production (metabolic balance) of the fragment. However, whether the re-attachment and asexual reproduction success simply depends on photosynthetic capacity warrants further mechanistic studies. Understanding the mechanisms of asexual reproduction in F. radicans is important in order to assess the dispersal capacity of this foundation species.

scholarly journals Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph

2019 ◽  
Vol 6 (8) ◽  
pp. 190677 ◽  
Author(s):  
Carina Nebel ◽  
Petra Sumasgutner ◽  
Adrien Pajot ◽  
Arjun Amar
Keyword(s):  
Response Time ◽  
Response Times ◽  
Bright Light ◽  
Light Level ◽  
White Background ◽  
Light Conditions ◽  
Dark Light ◽  
Light Levels ◽  
Columbia Livia ◽  
Colour Morphs

To avoid predation, many species rely on vision to detect predators and initiate an escape response. The ability to detect predators may be lower in darker light conditions or with darker backgrounds. For birds, however, this has never been experimentally tested. We test the hypothesis that the response time of avian prey (feral pigeon Columbia livia f. domestica ) to a simulated hawk attack (taxidermy mounted colour-polymorphic black sparrowhawk Accipiter melanoleucus ) will differ depending on light levels or background colour. We predict that response will be slower under darker conditions, which would translate into higher predation risk. The speed of response of prey in relation to light level or background colour may also interact with the colour of the predator, and this idea underpins a key hypothesis proposed for the maintenance of different colour morphs in polymorphic raptors. We therefore test whether the speed of reaction is influenced by the morph of the hawk (dark/light) in combination with light conditions (dull/bright), or background colours (black/white). We predict slowest responses to morphs under conditions that less contrast with the plumage of the hawk (e.g. light morph under bright light or white background). In support of our first hypothesis, pigeons reacted slower under duller light and with a black background. However, we found no support for the second hypothesis, with response times observed between the hawk-morphs being irrespective of light levels or background colour. Our findings experimentally confirm that birds detect avian predators less efficiently under darker conditions. These conditions, for example, might occur during early mornings or in dense forests, which could lead to changes in anti-predator behaviours. However, our results provide no support that different morphs may be maintained in a population due to differential selective advantages linked to improved hunting efficiencies in different conditions due to crypsis.

scholarly journals Effect of Intersection Lighting Design on Drivers’ Perceived Visibility and Glare

2019 ◽  
Vol 2673 (2) ◽  
pp. 799-810 ◽  
Author(s):  
Rajaram Bhagavathula ◽  
Ronald Gibbons ◽  
Maury A. Nussbaum
Keyword(s):  
Target Detection ◽  
Lighting Design ◽  
Visual Performance ◽  
Strong Positive Correlation ◽  
Likert Scales ◽  
Positive Correlation ◽  
Target Visibility

A systems-level approach to intersection lighting design has shown that illuminating the intersection box increases drivers’ nighttime visual performance. However, for an intersection lighting design to be effective and accepted, it should not only maximize visual performance but also enhance perceived visibility and minimize glare. The goals of this study were to assess the effects of different intersection lighting designs on these two outcomes. Visibility was assessed with respect to a pedestrian, several targets, and an intersection. Perceptions of visibility and glare were measured using Likert scales, with participants exposed to multiple lighting designs on a realistic intersection. Twenty-four participants completed the study, with an equal number of younger (18–35 years) and older (65+) drivers. The lighting design that illuminated the intersection box had the highest levels of perceived target and intersection visibility and the lowest ratings of glare. For the same lighting configuration, a strong positive correlation was also found between perceived target visibility and previous results on target detection distances. In this configuration, perceived visibility plateaued between 7 and 10 lux of mean intersection illuminance. Increased levels of perceived visibility in different conditions were likely a result of size and contrast differences, and the distribution of the luminaires used. These results suggest that illuminating the intersection box has multiple benefits, in that it not only increases visual performance but also increases perceived visibility and reduces glare.

Determination of spikelet number in wheat. II.* Effect of varying light level on ear development

1977 ◽  
Vol 28 (4) ◽  
pp. 575 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson ◽  
Y Aitken
Keyword(s):  
Light Level ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Spikelet Number ◽  
Rate Of Development ◽  
Light Levels ◽  
Two Factors ◽  
Lower Light ◽  
Ear Number

The effects of two light levels (0.98 and 4.90 cal cm-2 hr-1) on rate of development and spikelet number per ear were studied in eight wheat cultivars grown under a 16 hr photoperiod at 20°C. The objective was to ascertain how light affects spikelet number. At the lower light level the durations of the vegetative, spikelet and ear elongation phases were greater, but the number of spikelets per ear, number of phytomers present at floral initiation, final leaf number, number of phytomers that were converted into spikelets, apex length at floral initiation and rate of spikelet initiation were smaller than at the higher light level. Responses to varying light level for a11 these parameters were similar for different cultivars, but the sizes of the responses differed. Within a given cultivar, an increase in spikelet number was associated with longer apices at floral initiation and a higher rate of spikelet initiation. It was concluded that these two factors are important determinants of spikelet number. ___________________ *Part I, Aust. J. Agric, Res., 28: 565 (1977).

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