Lighting Research &Technology, Ahead of Print. An asymmetric road lighting concept known as Probeam is investigated in this study for energy efficiency, contrast and visibility of vertical objects and road markings in highway lighting. Calculations based on road lighting standards, road surface and markings reflection characteristics and typical Dutch highway geometry, reveal that Probeam lighting improves the average visibility of objects and road markings over symmetrical lighting, however, with a 14% increase in luminous flux as per current road lighting standards. This increase in lumi ..read more

Lighting Research &Technology, Ahead of Print. Daytime light levels are important for human physiology. Office workers spend most of their daytime inside buildings where it is unclear whether they receive healthy light levels. A recent publication presented recommendations for the minimum daytime light level for optimal human health, expressed in melanopic equivalent daylight illuminance (EDI). The current paper assesses whether this recommended daytime light level is achieved by office workers through a meta-analysis of personal light levels of office workers, obtained from light-dosimetr ..read more

Lighting Research &Technology, Volume 56, Issue 3, Page 309-310, May 2024 ..read more

Lighting Research &Technology, Volume 56, Issue 3, Page 223-224, May 2024 ..read more

Lighting Research &Technology, Volume 56, Issue 3, Page 221-222, May 2024 ..read more

Lighting Research &Technology, Volume 56, Issue 3, Page 247-249, May 2024 ..read more

Lighting Research &Technology, Ahead of Print. The spectral distribution is a fundamental property of non-monochromatic optical radiation. It is commonly used in research and practical applications when studying how light interacts with matter and living organisms, including humans. In the field of lighting, misconceptions about the spectral distribution of light are responsible for unfounded claims, which pervade the scientific and technical communities. Starting from the definition of the spectral distribution, this paper describes the ambiguities and errors associated with a purely grap ..read more

Lighting Research &Technology, Ahead of Print. At temporal light modulation (TLM) frequencies between 80 Hz and 20 000 Hz observers may perceive a series of repeated images called the phantom array effect (PAE) when they move their eyes in large saccades across a modulating light source or across a scene lit by the modulating light source. To date, there is no well-established measure for quantifying PAE visibility, but there is growing awareness of the need for one among design professionals and sensitive populations. This paper documents a new measure, the phantom array visibility measur ..read more

Lighting Research &Technology, Ahead of Print. Investigating the risk of road crashes associated with ambient light is often challenged by bias resulting from confounding effects of other risk factors. The study used the odds ratio and the risk ratio methods to isolate the effect of ambient light from other risk factors. This was possible in this research using the ‘whole-year’ approach adopted in previous research and utilising seasonal variations in ambient light in Cape Town. The analysis was based on crash and ambient light data collected between 2014 and 2018 in Cape Town. A total of ..read more

Lighting Research &Technology, Ahead of Print. The non-image forming effects of light are moderated by various aspects such as dose, spectrum or temporal and spatial patterns. One of them, the spatial distribution of light within the field of view, has been scarcely researched. Although few studies suggest effects on melatonin secretion during night-time, the daytime effects remain unknown. In this project, we investigated the effect of three light directions – from above, below and the side – each illuminating different retinal regions. The luminance and the size of the light source were ..read more