Subjective evaluation of luminance distribution for intelligent outdoor lighting

A large number of physical dimensions and different criteria make choosing the optimal luminance distribution for outdoor lighting difficult. The optimisation becomes even more complex for light-emitting diode-based lighting installations that can be intelligently operated, providing different luminance distributions around a moving traffic participant. This study aims at establishing the main subjective factors for the assessment of the luminance distribution of an intelligent light-emitting diode-based outdoor lighting installation for pedestrians. Semantic-differential scales and Likert scales have been used to identify subjective impressions and to find the main factors for the optimisation of the control of the luminance distribution. Our results reveal two factors that need to be considered when assessing intelligent outdoor lighting installations: a major factor that is related to the subjective feeling of well-being and a minor factor that is related to the physical properties of the environment.