Urban outdoor lighting : Pedestrian perception, evaluation and behaviour in the lit environment

Abstract: Walking plays an essential role in sustainable transport systems, as nearly all journeys in the urban environment incorporate walking in one way or another. In parts of the world, for long periods of the year, seasonal variation in daylight hours means that pedestrians must rely on outdoor lighting to make cities accessible after dark. However, outdoor lighting is associated with considerable energy use, generating financial and environmental costs, so there is a need to develop energy-efficient outdoor lighting applications that also meet user needs. There are standard measures stipulated in national and international standards for the photometric properties of outdoor lighting but, to date, there is no consensus on methods for assessing how pedestrians respond to lighting.This thesis aims to contribute to the understanding of the pedestrian response tooutdoor lighting when walking after dark. A series of four studies explores what urban design qualities pedestrians consider important in relation to neighbourhood walkability (Paper I), evaluates a set of methods for assessing the pedestrian response (in terms of perception, evaluation and behaviour) to outdoor lighting (Paper II), evaluates the applicability of the methods in a field setting (Paper III), and tests a new behavioural method of assessing pedestrians’ preferences for outdoor lighting applications (Paper IV).The results suggest that outdoor lighting is considered an important urban design quality that pedestrians consider when assessing the walkability of their neighbourhoods. Outdoor lighting that caters to user needs and contributes to accessibility and perceived safety facilitates walking, whereas insufficient lighting has a negative influence on the perception of safety, and makes people avoid walking after dark.The main finding from the evaluation of methods is that perceptual tasks (facial expression recognition and street sign reading) and evaluation instruments (perceived outdoor lighting quality scale and the composite affect measure) may be used to differentiate between lighting applications. The results also show that elderly people depend on outdoor lighting more for providing adequate seeing conditions. The results from the method development study indicate that the Random Environmental Walk method can be used for assessing the preference for different lighting applications, and that the results correspond to the results from self-rating scales.The thesis suggests a theoretical framework that bridges walkability and lighting, which may inspire and benefit future research regarding outdoor lighting for pedestrians. Methods that can differentiate between lighting applications are identified and evaluated, which may be used to guide the decisions of municipalities before they undertake major upgrades or new installations of outdoor lighting on urban pedestrian paths. The methods may also be useful for lighting designers, as a way to obtain complementary perspectives to those provided by lighting simulation software.