Due to different visual tasks and gaze patterns, the discomfort glare experienced by pedestrians may differ from that experienced by drivers. This paper investigates the discomfort glare experienced by pedestrians under various urban LED luminaires through psychovisual experiments conducted on a test track. The ability of state-of-the-art models to predict the level of discomfort glare, measured on the de Boer rating scale, for this application is also investigated. With one exception, the models all overestimate the mean subjective discomfort glare compared to the experimental data. Models proposed by Lin et al (2015) and Bullough et al (2008Bullough et al ( , 2011 perform well. However, the implementation of these models is not straightforward because choices are needed to estimate some of the variables such as the background luminance and the glare source area.

We developed a web application to investigate online-based experiments for the psychovisual assessment of luminous environments. We reproduced online a laboratory experiment conducted in a virtual environment, in which the luminous environment of an office room lit by different combinations of ambient/task lighting was assessed by observers. A control panel of 30 observers performed both experiments. Statistical analyses revealed no statistically significant differences between data collected in the laboratory and online. In addition, an online-based experiment involving 1114 observers was conducted to study the uncontrolled experimental conditions that may impact results. We show that, by increasing the panel size, bias, mainly related to the perceived contrast and brightness of the display and the brightness of the surrounding area is removed. Findings suggest that 100 observers are enough to remove bias.

A multi-objective methodology is proposed to optimise lighting solutions by taking into account not only energy objectives but also subjective ones such as visual preferences. The originality of this method lies in the integration of subjective data obtained from psycho-visual tests conducted with panels of observers potentially representative of end users, into a multi-objective optimisation framework. This method makes it possible to identify all the best tradeoffs and the direct correspondence between power demand and user visual preferences, to handle constraints, to handle inter-individual differences and to optimise preferences on various visual attributes at the same time. The methodology was developed through a pilot study of office lighting optimisation. The findings are consistent with previous work and provide additional application knowledge about the case study.

Road delineation treatments enhance the ability of drivers to control their vehicle safely on winding roads. A simulator experiment compared night-time driving on a country road under three conditions: on an unlit road, on a road illuminated on curves by typical road luminaires, and on a road with an active lane delineation application, where self-luminous road studs are turned on to outline the lane and road edges as the driver approaches and passes the curves. The unlit condition induces greater lateral position variability and longer crossovers relative to the studs condition, demonstrating better lateral vehicle control in the latter. The luminaires condition induce greater lateral position variability in left curves, and longer crossovers in right curves, relative to the studs condition, which also demonstrates a better lateral vehicle control in the studs condition. At a subjective level, the participants perceived both the studs condition and the luminaires condition as safer, more comfortable and allowing better control than the unlit road. It was concluded that the tested application enhanced the ability of drivers to control the virtual car, as compared to an unlit road or road lighting.

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