# Efficiency Analysis of Roadway Lighting Replacement in a Selected Polish Municipality
## 1 Introduction
According to the authors [7], the IoT-based (Internet of Things) Master-Slave intelligent LED-light-controlling system installed in a parking zone with few people results in energy savings of 90%. The system has been adopted and installed so that the brightness of the LED lights in the featured zone can be changed simultaneously to reduce energy consumption, and the parameters of the LED lights can be set directly. Upgrading public lighting systems by replacing existing luminaires with LED technology is a policy that many municipalities are adopting to reduce spending budgets as well as increase the environmental sustainability of a city. Furthermore, the introduction of innovative and flexible systems can be the first step toward a smart city approach. Retrofitting public lighting systems can increase energy efficiency and reduce maintenance costs and CO\({}_{2}\) emissions while improving lighting performance. On the other hand, it can significantly influence and change the night-time image and perception of urban and rural spaces. The current energy crisis means that particular attention should be given to retrofitting and the economic benefits of road lighting control systems, assuming that such systems satisfactorily meet the visual requirements of pedestrians and drivers. The installation of new lighting systems or the retrofitting of existing ones requires careful consideration in terms of design configurations that would maintain the average illuminance of the road surface, the uniformity of illumination and the variability of illumination as needed while meeting national regulations and guidelines. A separate but equally important topic is road construction safety, which is described in, e.g., [8; 9] and road user safety, which is influenced, among others, by road lighting quality. Street lighting is an indispensable part of the right-time urban landscape. It is important for road safety, the visual comfort of users, crime prevention and increased perceived personal safety. The implementation and maintenance of an adequate street lighting service are very costly for municipalities and have a significant impact on their budgets [10]. At present, high-pressure sodium lamps are widely used in street lighting. This is in part due to their high efficacy and relatively long lifetime. Their use, however, comes at the expense of good colour rendering. The results presented in [11] consistently show that at comparable illuminances, people perceive areas illuminated with white light to be brighter, safer and more comfortable than the same neighbourhood illuminated with yellowish light. The results in [12] showed that from an environmental perspective, it is advantageous to upgrade frequently to the latest technology in order to capture efficiency gains. According to the authors, the cost-optimal strategy is frequently not aligned with the environmentally optimal management strategy. An area that needs to be further explored in the future, both in the context of lighting and other technological industries, is the mechanism for resolving trade-offs between economically and environmentally optimal decisions. The authors [13] analysed the possible implications of retrofitting public lighting systems in small towns characterised by a prominent location, landscape context and widespread heritage. The paper evaluates the current lighting condition produced by traditional luminaires and the lighting condition produced by a retrofit proposal with LED sources from a case study located in the area of Maremma Grossetana in Tuscany. The authors compared the original and designed lighting solutions through simulations. They analysed the effects in terms of lighting and energy performance, as well as the implications for altering the nightscape. The results obtained by the authors confirm the positive impact of energy-efficient lighting systems on lighting performance, energy consumption and the perceived visual image of places.