Lighting Research & Technology

Thoughtfully designed outdoor lighting plays a significant role in supporting reassurance after dark. This study aims to explore the use of the public participation geographic information system (PPGIS) methodology to examine the relationship between reassurance and outdoor road lighting, focusing on participants’ everyday experiences. By employing PPGIS, which has seldom been used in urban lighting research, we investigate the associations between reported reassurance and actual lighting conditions, including the presence of lighting features and the requirements for various road lighting classes. Additionally, the study explores correlations between reassurance and perceived lighting parameters, such as overall quality of road lighting and brightness. Our findings confirm that the presence of lighting itself can positively contribute to reassurance and that unlit areas are perceived as less safe in comparison with areas with any lighting (i.e. P3 and P4 lighting classes). We also establish a positive correlation between reassurance and perceived lighting parameters, with distinct differences in these parameters observed between safe and unsafe places, where higher ratings are associated with areas reported as safe. Overall, the PPGIS methodology demonstrates considerable potential for further development and application in outdoor lighting studies, providing valuable insights for urban lighting design.

A laboratory experiment was conducted to examine the impact of different lighting conditions on melatonin derived from saliva samples, alertness as measured through reaction time (RT) to an auditory stimulus and self-reported sleepiness. This experiment replicated previous work but with the inclusion of an extreme condition to test the null findings of that previous work. There were four lighting conditions as defined by illuminance at eye level and spectral power distribution. Three conditions, having photopic illuminances of 0.5 lx to 8 lx (melanopic equivalent daylight illuminance (EDI) values of 0.5 lx to 10.4 lx) repeated the range used in previous work: the fourth condition extended this to 83 lx (melanopic EDI approximately 100 lx), which is extreme compared to those conditions typical of road lighting. The time period over which measurements were conducted was intended to represent pedestrian activity in the evening. The results revealed a significant reduction in RT and significant decreases in melatonin and subjective sleepiness only with the extreme condition, but did not suggest that lighting conditions typically used for road lighting had a significant effect on any of the dependent variables.

Cyclist visibility in road lighting environments is a key factor in reducing crash risks, particularly in conflict zones where interactions with motorised traffic occur. Existing lighting standards predominantly focus on horizontal illuminance, which does not sufficiently address the visibility challenges cyclists face in these high-risk areas. This study introduces a novel positive-contrast model that incorporates vertical illuminance as a supplemental parameter, specifically for conflict zones. The theoretical model assesses the impact of vertical illuminance on visibility levels, demonstrating that a minimum threshold is necessary to achieve positive contrast and prevent veiling effects that reduce conspicuity. A computational optimisation process was employed to identify feasible lighting configurations, and the model was validated through a simulation-based evaluation of light distribution curves. The findings indicate that optimised lighting designs can meet the proposed vertical illuminance requirements without excessive glare or energy consumption. Consequently, the study highlights the need for tailored luminaires to facilitate real-world validation and implementation of this approach. Further field studies are essential to verify these findings and establish practical design recommendations for urban lighting planners.

The presence of glass curtain wall LED media façade (G-L-M) along roads has disrupted the ambient light environment, impeded drivers’ visibility and posed potential risks to night-time driving safety. This study investigates the effects of G-L-M technical parameters on driving distraction by constructing night-time simulation scenarios and obtaining the driver’s reaction time for recognising small targets. The study revealed that the field of view, colour and state of G-L-M are the most crucial factors, whereas luminance and area have relatively minor effects. Specifically, the G-L-M located in the fovea centralis and peripheral field of view regions (−30° to −15°) were more likely to cause driving distraction than those in the central field of view. Red, green and blue are associated with higher reaction times and failure rates, whereas white has the lowest reaction time and failure rate. Additionally, we found that the difference between high and low luminance was not significant. However, appropriate high luminance can enhance the recognition rate of small targets. Dynamic G-L-M significantly increases reaction time compared to static G-L-M. This study can provide a reference for assessing the effects of G-L-M to ensure night-time roadway driving safety and for formulating future regulations and designing G-L-M lighting.

Mountainous highway single-vehicle crashes present higher fatality rate and are associated with relative poor lighting condition and driver’s route familiarity. This study examined three-year mountainous highway single-vehicle crashes to identify factors influencing injury severities of low route familiarity (LRF) drivers. Random-effects generalized ordered probit (REGOP) models were employed across daylight, dark and dark-lighted conditions. The impact of tunnel and driver’s failure to use a seatbelt on more severe injuries is particularly pronounced under daylight condition, while their effect diminishes under dark conditions. Dark and dark-lighted conditions amplify the risks associated with intersection and driver aged 65 years or older. Sharp turns are difficult for the LRF drivers to figure out, even under daylight condition. Adverse weather condition increases the probability of LRF drivers’ minor injuries under daylight condition, but decreases the probability of LRF drivers’ minor injuries under dark-lighted condition. Driver under alcohol influence increases the probability of LRF drivers’ major injuries by 16.7% under dark condition. These findings can help develop targeted countermeasures and proper policies for LRF drivers and alleviate their injury severities in single-vehicle crashes.

Light pollution poses a significant threat to nocturnal insects, yet our understanding of how insects are affected by lighting across ecosystems remains limited. We investigated differences in light-induced attraction regarding abundance, richness and diversity of moths between forest and grassland ecosystems. This novel study presents the first multi-site comparison of moth attraction across ecosystems using warm-coloured LED lighting (3000 K) that simulates typical road lighting conditions in both spectral composition and intensity. Using identical light traps with characterised lighting properties across 32 sites, we found significantly higher moth abundance and diversity in forests compared to open grasslands, with stronger environmental effects on moth attraction in open grassland ecosystems. Even at the low light intensities used in our experiment, which is comparable to spill light from road lighting in natural environments, we found significant impacts on moth activity, which is concerning given their limited activity periods. Moth families exhibited varying attractions across ecosystems, suggesting potential sampling biases in light attraction studies. Our comprehensive light characterisation using real-world lighting conditions provides a standardised framework for future research on light pollution impacts. The findings demonstrate the need for ecosystem-specific approaches in light pollution mitigation strategies and have important implications for conservation across diverse landscapes.