The Urban Light Plan: Toward Sustainable and Resilient Cities ^†

Abstract

Urban lighting is evolving from a basic technical infrastructure to a strategic tool for sustainable regeneration, energy efficiency, and public space reactivation. This paper explores the potential of smart and adaptive lighting systems as enablers of 24 h services, equitable access, and environmental resilience. By integrating lighting strategies with urban planning instruments (PRIC, PEC, PMU), cities can reduce energy consumption, limit light pollution, and foster new urban centralities. The study outlines regulatory gaps, technical solutions, and cultural shifts needed to transform lighting into a key asset for livable, inclusive, and digitally enabled urban futures.

1. Introduction

In recent years, growing attention to urban sustainability has led to an evolution in city regeneration strategies, which are no longer limited to building restoration or the simple conversion of brownfield sites, but aim at the overall reorganization of urban functions in an efficient, resilient, and inclusive manner [1]. In this context, public lighting is one of the key elements of transformation, both in terms of environmental impact and its ability to support new forms of livability and safety in urban spaces. However, its integration into sustainability-oriented urban policies requires a systemic and multi-level vision, based on cooperation between general urban planning tools and specific sectoral measures, such as Municipal Lighting Master Plans (PRIC), Municipal Energy Plans (PEC), and Urban Mobility Plans (PMU) [2].

Urban resilience refers to the ability of urban systems to absorb shocks (climatic, economic, health) and reorganise themselves adaptively, while sustainable urbanism integrates environmental, social and economic considerations into spatial planning in order to ensure efficient use of resources and a high quality of urban life in the long term.

Urban lighting design can actively contribute to improving the environmental performance of cities, reducing climate-changing emissions, decreasing light pollution, and optimizing management and maintenance costs. Far from being a purely technical or decorative element, urban lighting becomes a tool for spatial equity and social security, capable of extending accessibility to urban services even at night, reducing marginalization and perceived insecurity [3].

At the European level, numerous studies have shown that proper public lighting design can have positive effects in a number of areas: from air quality (thanks to reduced use of private vehicles and increased active mobility) to the physical and mental well-being of citizens and the protection of urban biodiversity, which is often compromised by excessive or incorrect use of artificial light at night [4,5]. In particular, the adoption of smart lighting systems, supported by sensor networks, artificial intelligence, and dynamic adaptation technologies, allows for precise and flexible light management based on actual pedestrian and vehicle flows, contributing to a significant reduction in consumption and emissions [6].

In Italy, however, there remains a lack of regulatory and implementation consistency between regions, with only a few local administrations equipped with advanced lighting planning tools and updated guidelines for light pollution control. Furthermore, the lack of interoperability between different territorial plans and databases constitutes a concrete barrier to the effective integration of sectoral policies into a single urban system geared towards sustainability [7]. In this scenario, scientific research plays a fundamental role in proposing replicable models, comparative evidence, and scalable solutions to promote smart cities capable of rebuilding themselves, minimizing the use of new resources, and optimizing existing networks [8].

This contribution fits within this theoretical and operational framework, with the aim of exploring—through case studies, regulatory references, and comparative analyses—how public lighting can become an enabling lever for environmental sustainability, energy efficiency, and urban quality of life. A multidisciplinary analysis is proposed that takes into account not only the technical and design aspects of lighting, but also its social, health, landscape, and environmental implications, offering useful insights for integrated and predictive governance of contemporary urban systems.

2. The Italian and Regional Regulatory Framework

In Italy, the regulatory framework governing public lighting and light pollution control has gradually taken shape through a series of regional provisions, municipal measures, and technical recommendations, often the result of local initiatives rather than a unified national policy. This approach has led to significant regional differences in the implementation of energy saving and night sky protection policies, with some regions particularly advanced and others—such as Calabria and Sicily—still lacking specific legislation in this area. Despite their diversity in content, regional regulations share some fundamental principles: limiting the upward dispersion of light flux, regulating the color temperature of light sources (especially to limit blue light emission), requiring the use of energy-efficient systems, and integration with land-use planning tools [9].

The bill currently under discussion in Calabria, entitled “Urgent measures for the containment of light pollution and energy saving and for the correct use of energy resources,” deserves a special mention [10]. It aims to fill the existing regulatory gap by proposing technical criteria for the design, installation, and management of outdoor lighting systems. The text defines light pollution as the product of artificial night-time lighting directed or reflected towards the sky, emphasizing how this phenomenon has intensified since the Second World War in conjunction with industrial growth and the increase in human activity at night [11]. The bill introduces limits on the color temperature of light sources, recognizing the potential negative effects of blue light not only on the environment but also on human health and ecosystems, as highlighted in the WHO guidelines [12] and recent neuroscientific research [13]. However, there is a need for greater regulatory harmonization and a monitoring system to verify the effectiveness of the policies adopted, also considering European decarbonization targets and EU directives on urban sustainability and biodiversity.

Alongside regional legislation, there are technical tools to support local planning, such as the Outdoor Lighting Analysis Document (DAIE), introduced in 2015, which in some cases can replace the PRIC. The DAIE reduces the administrative burden, but there are still no implementing decrees making its adoption mandatory and defining its minimum content, limiting its effectiveness as a systemic tool [14].

Integrated Municipal Tools: PRIC, PEC, PMU

The PRIC aims to map, classify, and design the municipal lighting network according to criteria of efficiency, safety, and environmental sustainability, providing design guidelines for new installations, replacements, or upgrades to existing systems. However, if the PRIC is not updated in line with urban and demographic developments, it risks becoming a static technical document, disconnected from the real dynamics of the city [15,16]. It is in this scenario that coordination between the PRIC, the Municipal Energy Plan (PEC) and the Urban Mobility Plan (PMU) become strategic. The PEC, which is required in many regions (e.g., Emilia-Romagna, Lombardy), defines local targets for reducing energy consumption and greenhouse gas emissions, often linked to projects to upgrade public lighting using LEDs, remote control systems, and renewable sources [17]. The PMU, on the other hand, aims to promote sustainable and accessible urban mobility and can benefit from adaptive lighting that improves the safety of cycle and pedestrian paths, the night-time use of public spaces, and intelligent traffic management [18].

Numerous studies suggest that the lack of interoperability between these tools compromises the strategic coherence of urban policies, hindering the implementation of integrated and synergistic projects [19]. A prime example is the planning of so-called ‘30 km/h zones’ or ‘15-min cities’, where lighting plays a crucial role in ensuring functional continuity, comfort, and safety on local routes, especially in the evening hours [20]. However, the logic of hybrid and multifunctional infrastructure requires regulatory and managerial updates that overcome the historical separation between municipal technical sectors, favoring collaborative and data-driven governance.

However, in the absence of clear and shared institutional direction, these tools risk remaining ineffective, generating institutional and managerial barriers that compromise the real integration of interventions.

Finally, the role of PRICs could be further enhanced through the use of interoperable GIS platforms capable of collecting and updating real-time data on the lighting network, energy efficiency, mobility flows, and environmental impacts. This data-driven approach has already been tested in several European municipalities and is compatible with the guidelines provided by PNRR funding and the European Horizon Europe and Urban Innovative Actions programs [21].

3. Urban Reuse and 24 H Services

The theme of urban reuse, understood as a strategy for sustainable regeneration, has taken on an increasingly central role in local and international urban agendas in recent years. The contemporary approach to redevelopment is not limited to the mere repurposing of abandoned buildings or spaces but extends to a systemic vision that considers the entire urban ecosystem and its ability to adapt, transform, and respond resiliently to the emerging needs of the community.

Within this vision, public lighting becomes a key device for activating services that can be used 24 h a day, capable of generating urban vitality even at night and ensuring functional continuity for the newly regenerated spaces. The possibility of making public or hybrid places (mixed spaces for collective services, cultural activities, co-working, sports, mobility) accessible even beyond traditional daytime hours is directly linked to the quality and efficiency of the lighting system, which must guarantee safety, visual comfort, sustainability, and consumption control [22,23].

Urban reuse should not be understood solely as building retrofitting, but as a genuine reallocation of functions, considering existing resources and the environmental costs associated with new construction.

One of the most delicate elements of this approach concerns the enhancement of “urban time”: a truly sustainable city should be able to function even in the evening hours, not only for production needs, but to guarantee the rights of active citizenship, access to culture and social inclusion [24,25]. However, it is essential to distinguish between conscious nighttime enjoyment and the tendency to turn the night into an extension of the day. As pointed out by various studies on light pollution and scientists who are experts in circadian rhythms, excessive nighttime exposure to artificial light (ALAN) can compromise public health and environmental quality. In this sense, smart lighting must be designed to allow safe and minimal movements (from point A to point B), without encouraging continuous human activity at night. The application of the five principles of responsible lighting—in particular principles 1 (necessity), 4 (limited duration) and 5 (minimum intensity)—represents a guide to balance accessibility and protection of human and environmental well-being [26,27].

This concept is closely linked to the idea of the “15-min city,” in which essential services must be accessible in a short time, even without a car. However, in order for this proximity to be effectively usable at all hours of the day and night, it is essential that public space is adequately lit, safe, and inclusive. Only through the integration of urban planning, energy infrastructure, and lighting design will it be possible to ensure true temporal accessibility and not just spatial accessibility [28].

Internationally, such approaches have been recognized as replicable best practices. Cities that focus on smart regeneration and adaptive planning show better indicators of urban quality of life, reduced emissions, and social inclusion. Public lighting is therefore a cross-cutting lever for enabling more resilient, usable, sustainable, and equitable spaces [29].

3.1. Light Pollution: Data, Impacts, and Prevention

Light pollution is one of the most significant side effects of urban modernization, often underestimated in the debate on environmental sustainability. It consists of the upward dispersion of artificial light at night, generated by public and private lighting systems that are inadequately shielded or oversized, which alter the natural balance of the day-night cycle, compromising the quality of the night sky and producing significant impacts on human health, ecosystems, energy consumption, and the landscape [30].

Numerous scientific studies have shown that excessive exposure to artificial light at night, particularly to blue light components (frequencies above 4000 K), can alter human circadian rhythms, disrupt melatonin production, and increase the risk of metabolic disorders, insomnia, depression, and cardiovascular disease [31,32]. In the ecological sphere, light pollution interferes with the biological cycles of numerous animal and plant species, especially nocturnal ones, altering feeding, migration, and reproduction behaviors, with negative consequences for urban and peri-urban biodiversity [33].

From an environmental and climatic point of view, excessive lighting contributes significantly to urban energy consumption. In Italy, according to ISPRA and European Green Public Procurement data, the average annual expenditure on public lighting is around €28.7 per inhabitant, compared to a European average of €13 per inhabitant and virtuous values such as Germany, which stands at €5.8 per inhabitant [34]. This gap highlights the need to review the design criteria for lighting systems, focusing not only on energy efficiency but also on limiting waste and reducing unwanted light emissions, in line with the principles of the circular economy and climate neutrality [35,36].

From a technical point of view, the prevention of light pollution requires the adoption of LED lamps with a color temperature ≤ 3000 K, shielded and downward-facing luminaires, dimmable and programmable systems, the use of sensors for dynamic adaptation, and centralized control technologies based on real-time data [37]. In addition, lighting planning should integrate GIS mapping of the night sky, sensitive areas (parks, observatories, nature reserves), and anthropogenic flows in order to optimize light distribution according to principles of minimum impact and maximum functional benefit [38].

Finally, public awareness plays a key role: educational campaigns, partnerships between local authorities, schools, and environmental associations, as well as participation in international programs such as Dark Sky and Cities at Night, can encourage more responsible behavior and promote a culture of sustainable lighting based on moderation, the beauty of the starry sky, and respect for the natural rhythms of urban and non-urban life [39].

3.2. Smart Lighting and Dynamic Management

The evolution of urban public lighting is undergoing a profound transformation thanks to the introduction of digital technologies, sensors, and automated control systems that converge in the smart lighting paradigm. This innovative approach makes it possible to move beyond the traditional “static” model of lighting management—based on fixed schedules, constant light levels, and poor adaptability—to adopt dynamic, adaptive, and predictive operating logic, in line with the principles of smart cities and digital transition. Smart lighting systems, based on wireless mesh or LoRaWAN networks, integrate IoT (Internet of Things) technologies, artificial intelligence algorithms, and centralized management platforms capable of adjusting light intensity based on environmental parameters (residual natural light, weather conditions), flow data (presence of vehicles or pedestrians), extraordinary events (emergencies, public demonstrations), and customized time profiles for different urban areas. In this way, lighting becomes a flexible and context-sensitive infrastructure, capable of reducing energy consumption, improving perceived safety, and minimizing light pollution. According to recent studies, the adoption of smart lighting technologies allows for a reduction in consumption of up to 60% compared to conventional systems, thanks to the use of high-efficiency LED lamps, automatic control systems, and predictive maintenance. The latter represents an additional advantage, as the collection and real-time analysis of device operating data allows for targeted intervention, reducing operating costs and increasing the life of the systems. From an operational point of view, it is essential that the adoption of smart systems is not limited to a mere technological replacement, but is supported by a strategic and integrated vision, involving the updating of the PRIC, data sharing between municipal sectors, and interoperability between digital platforms. In this sense, lighting can become a driver for urban transformation, stimulating energy efficiency, social inclusion, and innovation in public services. The effectiveness of smart lighting also depends on the ability to collect, manage, and interpret large amounts of data (big data) from sensors distributed throughout the territory. This opens up promising scenarios for the development of predictive models, the identification of patterns of urban space use, and the definition of evidence-based policies. However, this evolution also poses new challenges related to cybersecurity, personal data protection, and algorithmic governance, which must be addressed through updated regulations and cross-cutting skills in the public sector [40].

Despite the transformative potential of smart lighting technologies, the large-scale implementation of such systems also presents significant challenges. Among the main barriers are economic ones, linked to the high initial costs of infrastructure; social issues, such as the uneven acceptance of citizens or the lack of understanding of the actual benefits; technical, due to the fragmentation of standards and technological obsolescence; and institutional issues, related to the lack of interoperability between entities and the lack of planning and management capacity on the part of local administrations. Furthermore, the absence of a critical evaluation of European experiments can lead to an uncritical replication of models that are not fully transferable to Italian contexts, where the urban, regulatory and cultural fabric presents significant peculiarities. One of the biggest challenges is the so-called institutional and infrastructural “lock-ins”, which prevent the adoption of flexible and adaptive approaches. Therefore, a sustainable design of urban lighting should include mechanisms for monitoring, impact verification, and citizen participation from the initial stages, so as to minimize risks and maximize the effectiveness of interventions.

4. Comparison with European Experiences and Replicable Models

In Europe, some cities have already embarked on advanced paths of integration between sustainable urban planning, optimization of public lighting, and intelligent use of technology. Among these, Barcelona represents one of the best-known and most replicable models, thanks to the implementation of the “Superblocks” (Superilles) project, conceived by urban planner Salvador Rueda, with the aim of returning public space to people, reducing pollution, and promoting soft mobility. The Superblocks model involves reconfiguring the urban grid into units of approximately 400 × 400 m, within which private vehicle traffic is restricted and the presence of pedestrian areas, green spaces, public services, and local cultural activities is enhanced. In this context, public lighting has taken on a key role in the perceptual and functional transformation of space, helping to improve visual comfort, night-time safety, and overall environmental quality. Barcelona has adopted an adaptive smart lighting strategy, with variable-intensity LED streetlights, distributed sensors, and a centralized control system. This has reduced energy consumption by up to 30%, increased the lifespan of lighting fixtures, and improved facility management through targeted predictive maintenance. The project has demonstrated how sustainable and smart public lighting can be a tool for social cohesion, inclusion, and neighborhood revitalization, as well as a lever for urban efficiency.

Other virtuous examples can be found in Freiburg (Germany), where the Vauban neighborhood was developed according to Positive Energy District principles, integrating solar-powered public lighting and shared electric mobility, and in Copenhagen, which has implemented networks of smart streetlights connected to environmental sensors for monitoring air quality and traffic flows.

A common element in all these experiences is the ability to integrate technology and governance, overcoming fragmentation between different administrative levels and promoting the active participation of citizens in defining interventions. In these cases, lighting is no longer conceived as an isolated technical function, but as a cross-cutting component of urban strategy, capable of simultaneously responding to environmental, social, cultural, and symbolic needs.

These European models offer valuable insights for the Italian context, where public lighting is often still treated in a sectoral manner and disconnected from other urban policies. The adoption of a systemic approach, based on the synergy between PRIC, PEC, and PMU, and supported by interoperable digital tools, could contribute significantly to achieving the objectives of climate neutrality and urban quality, in line with the European agendas for green and digital transition.

5. Conclusions

Public lighting, historically considered a marginal technical infrastructure, is acquiring a strategic role within urban policies geared towards sustainability, energy efficiency, and environmental resilience. As demonstrated by the experiences analyzed and the evolving regulatory framework, urban lighting is no longer just a tool for nighttime visibility, but a multifunctional device that affects quality of life, safety, territorial equity, and the usability of public space. The adoption of smart, dynamic, and interoperable lighting systems, combined with the integration of various municipal planning tools, represents one of the most urgent and promising challenges for the regeneration of existing cities. This integration not only allows for a significant reduction in energy consumption and CO₂ emissions, but also enables the efficient reorganization of urban functions, promoting the reuse of marginal areas and the location of 24 h services in areas that already have infrastructure and high energy availability.

However, the Italian context still highlights significant critical issues related to regulatory and operational fragmentation, the absence of a national framework law on light pollution, and the lack of integrated digital tools for urban data management. To overcome these limitations, a reform is desirable that introduces minimum technical standards that are uniform at the national level, updating requirements for municipal PRICs, and multi-level governance capable of coordinating public and private actors and citizens.

In summary, urban lighting is now a true enabling infrastructure for ecological and digital transitions, capable of triggering virtuous processes of innovation in public services, enhancing existing heritage, and building more livable, inclusive, and resilient cities. For this to happen, a paradigm shift is needed to transform lighting from a passive cost to a strategic investment for the city of the future. Future prospects include the need to investigate the correlations between public lighting and public health, the impact of edge computing and digital twin technologies in the management of energy and urban flows, as well as the exploration of new models of participatory governance in the definition of urban lighting policies. In addition, there is an urgent need to develop multi-criteria evaluation criteria for lighting policies, integrating environmental, social, energy and perceptual indicators.