## 5 Conclusions
(2) The lighting compliance value was established: For all case studies where Sn \(\geq\) 1.00, lighting compliance is achieved, i.e., sustainable city lighting is also ensured towards efficient energy consumption and reduced light pollution. (3) Correlation Insights: There are correlations between Sn and various psychological and aesthetic-functional factors. An extended factor analysis can provide valuable insights into the variables that influence environmental comfort the most. However, using the statistical coefficient Sn is an equivalent tool that allows us to get results faster. (4) Deep dive into sociological factors: A detailed examination of the correlation of sociological factors and Sn, especially individual activities such as \"playing\", \"sitting\" and \"walking\", provides a more detailed understanding of human behavior in illuminated spaces. In conjunction with [PERSON]'s theory, this provides a solid framework for anticipating and shaping human activities in urban spaces. With the exception of walking, all activities correlate with Sn. (5) Confirmation of the hypotheses: The research successfully confirms the hypothesis that it is possible to develop a suitable and simple method to assess the quality of the light ambience in different urban open spaces. The introduction of the sustainability coefficient (Sn) effectively quantifies the compliance of urban lighting with the principles of sustainable design by integrating subjective factors such as illumination likability and perceived illuminance intensity. We have confirmed that the value of the sustainability coefficient warns us against excessive lighting. The subjective perception of intense lighting with low lighting sympathy only leads to energy loss and light pollution. The results of the study confirm the effectiveness and applicability of the Sn in real environments and pave the way for improved lighting concepts in cities where environmental friendliness and visual safety are paramount. (6) Recommendations for practical implications: The research offers actionable recommendations. These include possible adjustments to lighting intensity, aesthetic improvements, or even complete architectural redesigns. This practical dimension ensures that the results of the study can be directly applied in urban planning and design. The inclusion of specific places as case studies gives the results a real context that makes them comprehensible and implementable. It provides other cities or researchers with a benchmark against which they can compare their outputs or replicate the study in their own context. In summary, it can be said that the sustainability coefficient (Sn) can be used normatively in urban planning to define sustainable and user-oriented lighting standards. By using Sn as a benchmark, cities can regulate lighting systems to meet thresholds for both energy efficiency and subjective factors, such as ease of lighting and perceived illuminance. Regular assessments using Sn can guide retrofit and optimization measures, while public procurement can require that lighting projects balance environmental sustainability and human-centered design. Sn can also be used in the redesign of cities to ensure that lighting improves environmental comfort, perceived safety, and aesthetic quality. In addition, incorporating Sn into sustainability certification programs and community feedback mechanisms can help align lighting solutions with public needs and environmental goals. Future studies that delve deeper into public surfaces will be essential to further demystify the complicated dynamics of urban lighting preferences. To improve the generalizability of results, future studies should aim to analyze a broader range of urban locations, possibly across multiple cities or even countries. Longitudinal studies could also investigate how changes in urban lighting over time (either through technological advances or deliberate interventions) affect Sn value and people's perception of spaces.