Outdoor Lighting Quality for Pedestrians at Night: The Effects of Reduced Light Levels

ObjectiveThe aim of this field study was to explore the effects of a light reduction strategy on various qualitative and quantitative outdoor lighting quality criteria.BackgroundSeveral outdoor lighting quality criteria have been highlighted in previous work related to perception and evaluation from pedestrians. Previous studies revealed that a decrease of horizontal illuminance impacts criteria, and that individual moderators need to be considered.Method70 participants had to walk on different footpaths with a reduced luminous flux at night. They completed a questionnaire and tasks about perception and evaluation of outdoor lighting quality.ResultsThe results highlight an effect of the luminous flux and/or footpath on each criterium excepted discomfort from glare. A reduced luminous flux of 50% increases perceived visibility, visual acuity, and overall lighting quality compared to a flux at 10%. Differences in layout impact perceived visibility, perceived safety and overall lighting quality. Women have a lower perceived safety score than men, which is reflected in both quantitative and qualitative content. Elderly people have poorer visual acuity and mention brightness and darkness less often when describing the footpaths.ConclusionsThrough the mixed quantitative and qualitative approach conducted, the results confirm the impact of the lighting levels reduction on outdoor lighting criteria and are closely dependent on the context and location chosen.ApplicationsTaking into account the individual variability in decision-making processes could help local authorities to conduct policies of light reduction to limit the impact on the environment and to adapt urban lighting to everyone.