Electric Vehicles and Urban Tourism in Smart Cities: A Bibliometric Review of Sustainable Mobility Trends and Infrastructure Development

Abstract

This study presents a bibliometric review of global research trends on electric vehicles (EVs) and urban tourism within the context of smart cities, emphasizing the economic and policy dimensions of sustainable mobility and infrastructure investment. Drawing from 593 publications indexed in the Web of Science from 2005 to April 2025, the analysis explores document types, leading research areas, alignment with Sustainable Development Goals (SDGs), influential authors, and highly cited works. A keyword co-occurrence analysis reveals six major thematic clusters, highlighting key topics such as EV adoption behavior, renewable energy policy, wireless charging technology, and semiconductor innovation. Engineering and physics emerged as dominant research areas, with SDG 7 (Affordable and Clean Energy) and SDG 11 (Sustainable Cities and Communities) most frequently represented. The findings underline a growing interdisciplinary effort to integrate EV technologies with urban tourism through smart, carbon-neutral transport systems, supported by policy frameworks, green investment incentives, and digital infrastructure. This review identifies research gaps and opportunities to advance energy-efficient, economically viable, and tourism-oriented mobility solutions in smart cities by mapping the current knowledge landscape.

1. Introduction

The 21st-century urban landscape is profoundly transformed, driven by rapid advancements in digital technologies and the growing imperative for environmental sustainability [1]. Smart cities have emerged as a strategic response to these challenges, integrating information and communication technologies (ICTs) to optimize urban operations, improve the quality of life for residents and visitors, and promote resource-efficient systems [2]. Central to the smart city paradigm is the redesign of urban mobility frameworks, particularly the transition from conventional, fossil fuel-based transportation to electric and digitally connected transport modes [3]. This shift is not only essential for reducing greenhouse gas emissions and improving air quality but also crucial for reshaping how people experience and navigate cities, especially in the context of urban tourism [4].

Urban tourism plays a critical role in the socio-economic development of cities, contributing to employment, cultural exchange, and global connectivity [5]. However, the rise in urban tourism also places increased pressure on city infrastructures, including transportation networks, energy systems, and environmental resources [6]. The integration of electric vehicles (EVs) into urban tourism systems presents a viable solution to mitigate these pressures [7]. From electric buses and trams to e-scooters and e-bikes, these modes offer tourists cleaner, quieter, and more energy-efficient ways to explore urban environments [8]. Yet, the successful deployment of EVs in tourism-centric smart cities is contingent upon the availability of robust, intelligent infrastructure, particularly the technological systems that support charging, navigation, energy management, and intermodal connectivity [9].

The Internet of Things (IoT) is at the heart of this intelligent infrastructure [10]. By enabling seamless communication between vehicles, energy grids, transport platforms, and user interfaces, IoT facilitates real-time data collection and decision-making [11]. In tourism-heavy cities, IoT-based systems can enhance the management of EV fleets, optimize traffic flows, guide tourists to nearby charging stations, and monitor environmental impacts [12]. Moreover, IoT supports the broader goals of energy conservation and sustainability by aligning vehicle usage with renewable energy availability, reducing idle energy consumption, and extending the operational lifespan of EV infrastructure [13].

Despite the growing recognition of the potential synergies among EVs, urban tourism, and IoT in smart city ecosystems, the academic literature on this interdisciplinary nexus remains fragmented. Existing studies tend to focus on one aspect such as EV adoption, smart transport, or sustainable tourism, without systematically analyzing how these elements interact within a smart city context [14]. There is a pressing need for a comprehensive and integrative assessment of the scholarly landscape that connects these domains, identifies research trends, and highlights key areas for innovation and policy development.

Despite these advances, existing studies exhibit several shortcomings that limit their practical and theoretical contribution. First, most prior research isolates electric mobility from urban tourism systems, resulting in fragmented insights that fail to capture the integrated nature of smart city ecosystems. For example, Singh et al. [15] show that less than 5% of EV-focused studies incorporate tourism-related variables, and these often lack contextual urban infrastructure data. Second, comparative analyses remain scarce, with a dominant reliance on descriptive or conceptual frameworks rather than quantitative evaluations of infrastructure or policy efficiency. This limitation is evident in the minimal application of advanced benchmarking techniques, such as dual-signal optimization or integrated IoT-based control strategies, which are increasingly critical for real-time mobility solutions. Finally, there is insufficient empirical discussion on interoperability issues and the scalability of charging systems in tourism-intensive areas, despite reports of service inefficiencies in destinations with fluctuating demand (e.g., 20–30% charging downtime during peak tourist seasons in pilot projects across EU cities). These gaps underscore the need for a holistic bibliometric review that not only maps existing research but also identifies areas for methodological and technological improvement.

To bridge this gap, the present study employs a bibliometric analysis to systematically examine the body of scholarly work at the intersection of electric vehicles, urban tourism, and smart cities, with a particular emphasis on the enabling role of IoT in infrastructure development. Bibliometric methods offer a quantitative approach to mapping scientific knowledge, revealing patterns in authorship, collaboration networks, thematic evolution, and research hotspots. By synthesizing the existing literature, this study aims to offer strategic insights for academics, urban planners, tourism managers, and energy policymakers interested in promoting smart, sustainable, and tourist-friendly urban environments.

The main objectives of this study are threefold: (1) to analyze the evolution and publication trends in scientific research on electric vehicles in relation to urban tourism within smart city frameworks; (2) to explore the role of IoT and related technologies in supporting EV infrastructure and sustainable urban mobility; and (3) to identify co-occurring themes, and emerging research clusters within the global scientific discourse. Ultimately, this paper seeks to contribute to the broader understanding of how technological innovation can drive energy-efficient, environmentally responsible, and user-centered mobility solutions in the tourism-oriented smart cities of the future.

2. Literature Review

2.1. Electric Vehicles in the Context of Smart Cities

Electric vehicles (EVs) have gained significant traction as sustainable alternatives to traditional internal combustion engine vehicles, particularly within the framework of smart cities. Numerous studies have highlighted the environmental benefits of EV adoption, including reductions in greenhouse gas emissions, lower urban noise levels, and improved energy efficiency [9,16]. Smart cities, which prioritize data-driven governance and sustainable urban development, are increasingly investing in the electrification of public and private transportation systems. According to recent literature, the deployment of EVs in smart cities is closely linked to infrastructure readiness, including the strategic placement of charging stations, integration with renewable energy sources, and alignment with urban transport policies [17,18]. However, successful implementation requires more than vehicle adoption, it necessitates the development of intelligent, connected systems that can manage energy flows, monitor usage, and optimize routes. This complexity is particularly evident in tourism-intensive urban centers, where fluctuating visitor numbers demand scalable and adaptive transport systems [19].

2.2. Sustainable Urban Tourism and Mobility

Urban tourism is a rapidly expanding sector that significantly contributes to the economic development of cities, yet it also presents challenges related to congestion, emissions, and resource consumption [20,21]. In response, scholars have emphasized the need to align tourism strategies with sustainability goals, particularly through green mobility initiatives [22]. The integration of EVs into urban tourism strategies has been identified as a means of reducing the environmental footprint of tourist transportation while enhancing the overall visitor experience [23]. For instance, the use of electric shuttle buses, e-bikes, and e-scooters offers flexible, eco-friendly options for tourists navigating city centers.

Studies further suggest that sustainable mobility in tourism can reinforce destination branding, especially in cities aiming to project an image of innovation and environmental responsibility [11]. Technological innovations and emerging mobility systems are critical in shaping sustainable urban tourism within the framework of smart cities [24]. Nonetheless, the success of such initiatives is contingent upon cross-sector collaboration, investment in infrastructure, and the adoption of digital technologies that support user engagement and operational efficiency [25].

2.3. IoT and Smart Infrastructure for EVs

The Internet of Things (IoT) has emerged as a cornerstone of smart city architecture, enabling real-time connectivity among physical systems, digital platforms, and human users. In the context of electric mobility, IoT facilitates the management of charging infrastructure, vehicle diagnostics, traffic optimization, and energy consumption [26,27,28]. Recent studies emphasize that IoT-enabled platforms can greatly enhance the coordination of EV fleets, provide predictive maintenance data, and align charging patterns with renewable energy availability [29]. For instance, an intelligent recommendation system for EV charging stations can significantly improve accessibility and promote sustainability in smart tourism cities [30].

Moreover, IoT technologies are increasingly being used to support tourist mobility [31]. Smart applications that integrate GPS navigation, local attraction suggestions, EV charging maps, and multimodal trip planning are improving tourist experiences while reducing urban pressure points [32]. However, gaps remain in terms of interoperability between systems, data security, and the equitable distribution of smart infrastructure across different urban districts.

2.4. Bibliometric Analyses in Smart Mobility and Tourism Research

Bibliometric analysis has gained popularity as a method for mapping scientific landscapes and uncovering hidden patterns within large bodies of literature [33]. In recent years, several bibliometric studies have examined topics such as smart city development, EV adoption, and sustainable tourism [7,15]. However, there remains a notable gap in integrative studies that examine the convergence of EVs, IoT, and urban tourism within the context of smart cities. A systematic bibliometric investigation can reveal key research clusters, co-authorship networks, influential publications, and emerging trends, thus informing future research and practice [34]. This study addresses the aforementioned gap by offering the first comprehensive bibliometric analysis of literature at the nexus of electric vehicles, sustainable urban tourism, and IoT-enabled infrastructure in smart cities. In doing so, it contributes to a growing but fragmented body of knowledge and provides a strategic overview of current academic discourse and future directions.

3. Research Methodology

This study adopts a quantitative bibliometric approach to examine the evolution and structure of scholarly research related to electric vehicles, smart cities, urban tourism, and the Internet of Things (IoT). Bibliometric methods have proven effective in mapping the intellectual structure and identifying emerging trends in various research domains, particularly those involving technology and sustainability [35]. This method provides a systematic overview of the academic literature, allowing for the identification of influential authors, collaborative networks, keyword trends, and thematic clusters within the selected research field [36].

The data were collected from the Web of Science (WoS) Core Collection, a widely recognized and reputable database for bibliometric analysis. The search strategy was carefully designed using relevant keywords and Boolean operators to capture a comprehensive dataset. The search string included combinations of terms such as “electric vehicle *,” “e-mobility,” “smart cit *,” “urban tourism,” “sustainable tourism,” “IoT,” “Internet of Things,” and “smart technology.” Specifically, the Boolean logic applied was formulated as follows:

TS = ((“electric vehicle *” OR “e-mobility”) AND (“urban tourism” OR “sustainable tourism”))

(1)

where TS denotes the Topic Search field in Web of Science, ensuring retrieval of documents whose title, abstract, or keywords contain these terms.

This search was limited to documents published between 2005 and April 2025 to focus on the most recent and relevant contributions reflecting contemporary developments in electric mobility and smart infrastructure.

After retrieving the initial set of records, the data were filtered to include only peer-reviewed journal articles, review papers, and conference proceedings published in English. A manual screening process was employed to eliminate duplicates and irrelevant records based on titles, abstracts, and keywords. This process resulted in a final dataset of 593 publications for in-depth bibliometric analysis.

The bibliometric analysis was conducted using VOSviewer [37] and Bibliometrix (R-package) version 4.1 for bibliometric studies [36]. VOSviewer 1.6.20 was employed to generate network visualizations for co-authorship, co-citation, and keyword co-occurrence. These visualizations enabled the identification of key collaboration patterns, intellectual linkages, and conceptual structures within the research domain. Bibliometrix was used for descriptive statistics, including annual publication trends, top contributing authors, countries, and journals. Additionally, thematic mapping and trend analyses were performed using the Biblioshiny interface to capture the evolution of research themes over time.

4. Results and Discussions

4.1. Descriptive Analysis of Publication Trends

The publication trend on the topic of electric vehicles (EVs), urban tourism, and smart city infrastructure demonstrates a clear trajectory of increasing scholarly interest over the past three decades (Figure 1). Between 2005 and 2009, research activity remained limited and sporadic, with annual publication counts generally below five. This early period can be described as exploratory, where foundational concepts related to sustainability and early-stage smart transport systems were likely being formulated. For instance, the year 2005 saw only nine publications (1.518% of the total), while several other years before 2010 had just one or two documents. These early contributions, though limited in volume, laid the conceptual groundwork for future academic developments in the field.

A noticeable shift occurred after 2010, marking the beginning of a developmental phase. From 2011 onward, there was a significant and consistent rise in the number of publications. The year 2011, in particular, experienced a spike with 50 documents (8.432%), indicating a growing academic recognition of the convergence between smart mobility, sustainability, and urban planning. This surge aligns with the emergence of electric vehicles in commercial markets, urban sustainability goals, and technological advances such as the Internet of Things (IoT). The momentum continued, with 2016 also registering 50 publications, signaling sustained academic engagement and the deepening of interdisciplinary exploration in the area.

The period between 2018 and 2024 marks the maturation phase in the research landscape. Scholarly output during these years was consistently high, with 2016 to 2024 each contributing between 37 and 71 publications annually. The peak was reached in 2024 with 71 records (11.973%), reflecting a culmination of technological, environmental, and policy-driven imperatives that have brought electric vehicles and smart mobility solutions to the forefront of academic inquiry. This phase reflects a convergence of smart technologies—such as IoT for traffic and energy optimization, artificial intelligence for route planning, and blockchain for secure data sharing—with urban tourism strategies, aiming to make cities more livable and tourist-friendly.

Although data for 2025 remains incomplete, the presence of four publications already suggests continuing momentum. This forward-looking trend implies that research on EVs and urban tourism within the framework of smart cities will remain a focal point. Future studies are expected to delve deeper into advanced topics, including real-time data management, AI-driven urban mobility platforms, and decentralized energy systems. The integration of digital technologies is likely to reshape how electric mobility is conceptualized and implemented in tourism-centric urban environments.

4.2. Document Type Distribution

An analysis of the document types reveals a dominance of conference proceedings, with 463 records, accounting for the majority of the total dataset (Figure 2). This prevalence suggests that the field of sustainable mobility, especially as it relates to electric vehicles (EVs), urban tourism, and smart cities, is evolving rapidly, and researchers are keen to disseminate their findings promptly through conferences. These venues typically foster interdisciplinary discussions and timely updates on emerging technologies such as the Internet of Things (IoT), blockchain, and AI—technologies that are central to smart infrastructure development.

In contrast, journal articles constitute 171 documents, reflecting a significant body of peer-reviewed, in-depth research. These articles likely provide comprehensive investigations into specific aspects such as EV infrastructure, smart city governance, and sustainable tourism policies. The lower volume compared to proceedings may indicate the relatively nascent stage of consolidated theoretical frameworks in this interdisciplinary field.

Review articles are notably sparse, with only 10 records, underscoring the need for more synthesizing works that can integrate and critically assess the diverse strands of literature emerging across technology, mobility, and tourism domains. Early access articles (6) represent cutting-edge research that is awaiting formal publication, suggesting ongoing innovation and relevance of the topic. Lastly, only 1 book review was identified, likely reflecting limited engagement with monographic or conceptual literature in this fast-moving area.

The dominance of conference papers aligns with the field’s technological and applied orientation, where rapid iteration and feedback are essential. However, the relatively lower number of review articles highlights a research gap—pointing to opportunities for scholars to consolidate findings, bridge disciplinary silos, and guide future inquiry into sustainable urban mobility and its technological underpinnings

4.3. Research Area Distribution

The distribution across research areas in Figure 3 underscores the inherently multidisciplinary nature of sustainable mobility in smart cities, particularly concerning electric vehicles (EVs) and urban tourism. The field is predominantly rooted in engineering, which accounts for 239 documents (40.30%), reflecting the critical role of engineering in developing infrastructure, electric transport systems, and sustainable urban solutions.

Closely following is physics, with 190 documents (32.04%), signifying its foundational contribution to the design and performance optimization of electric vehicle components, battery systems, and energy-efficient technologies. This high representation of physics-related research aligns with the technical demands of smart mobility systems.

Instruments and instrumentation contribute 69 documents (11.64%), highlighting the importance of sensors, monitoring systems, and data collection tools—key enablers of IoT integration in smart mobility. Similarly, computer science holds 55 documents (9.28%), reflecting the growing incorporation of AI, machine learning, and blockchain in the planning and management of urban transportation and tourism systems.

Other notable areas include materials science (7.76%), vital for improving EV components and infrastructure durability; automation and control systems (7.08%), which support autonomous driving and smart traffic systems; and energy and fuels (6.58%), which focus on alternative and sustainable energy sources crucial for powering EVs.

Nuclear science technology, transportation, and science and technology—other topics each constitute 6.58–6.07% of the total. The presence of nuclear science may reflect research on high-density power solutions or policy comparisons, while transportation research underpins logistics, urban planning, and mobility trends. The “other topics” category indicates broader technological and interdisciplinary concerns not easily classified into traditional domains

4.4. Alignment with Sustainable Development Goals (SDGs)

The bibliometric data indicates a strong alignment between the literature on smart cities, sustainable mobility, and electric vehicles (EVs) with several United Nations Sustainable Development Goals (SDGs), affirming the relevance of this research domain to global sustainability agendas.

The most significant concentration of research is associated with SDG 7: Affordable and Clean Energy, comprising 202 records, underscoring the field’s central focus on transitioning to clean energy solutions. Closely following is SDG 11: Sustainable Cities and Communities, with 173 records, reflecting the critical importance of urban innovation, mobility, and planning in the broader discourse of smart and sustainable urban ecosystems.

Climate Action (SDG 13) is the third most represented goal, with 130 records, highlighting the emphasis placed on environmental impacts, emissions reduction, and climate-resilient infrastructure. Together, these top three SDGs illustrate the interlinked priorities of energy transition, urban transformation, and climate resilience in the context of smart mobility and city development.

Good Health and Well-being (SDG 3), with 62 records, represents the health-related benefits of sustainable urban design and clean transportation. Other goals with moderate representation include Life Below Water (SDG 14) and Life on Land (SDG 15), each with 15 records, which may relate to the indirect environmental benefits of reduced emissions and cleaner urban infrastructure.

Lesser-emphasized SDGs such as Zero Hunger (11 records), Responsible Consumption and Production (12 records), and Industry, Innovation and Infrastructure (7 records) still contribute to the holistic understanding of sustainability within this field, albeit from more specialized angles. Goals like Quality Education (5 records) and Decent Work and Economic Growth (5 records) suggest that while human development outcomes are acknowledged, they are less central to current research trajectories.

Of note is the very limited engagement with Reduced Inequality (SDG 10), represented by only 1 record, indicating a significant gap in equity-related research, such as the accessibility of sustainable mobility solutions for vulnerable populations.

This SDG alignment analysis reveals that while the field is firmly grounded in technological and environmental imperatives, there is scope for broader integration of social equity, educational, and economic dimensions to fully realize the inclusive promise of smart cities and sustainable mobility (Figure 4).

4.5. Research Trend

The keyword co-occurrence network reveals a rich and interconnected research landscape on electric vehicles (EVs) and their role in urban tourism and smart cities. Six distinct clusters demonstrate the interdisciplinary nature of sustainable mobility studies, particularly in relation to smart infrastructure, policy frameworks, user behavior, and technological innovation (Figure 5). This bibliometric analysis identifies core research themes that shape the discourse around electric vehicles and their integration into urban tourism ecosystems (

Table 1. Keywords in each cluster.

Cluster	Keywords	Occurrences	Total Link Strength
Yellow	batteries	5	4
	electric vehicle	79	51
	Hybrid electric vehicle	8	5
	management	14	23
	smart grid	7	12
Red	adoption	10	22
	attitudes	5	9
	behavior	6	4
	charging infrastructure	8	15
	CO2 emissions	5	8
	mobility	9	14
	policy	7	15
	renewable energy	8	12
	sustainability tourism	5	11
Green	optimization	20	24
	battery charger	7	8
	ev	8	4
	energy	8	20
	power	5	11
	stability	5	1
	strategy	5	13
	system	12	22
Blue	Photoluminescence	19	33
	doping	5	13
	gan	12	23
	growth	9	11
	mbe	7	14
	mocvd	5	7
	movpe	8	15
	structure	6	11
	zno	5	7
Light blue	high efficiency	5	4
	inductive power transfer	5	1
	spectroscopy	6	5
	wireless charging	5	6
	wireless power transfer	12	11
	X-rays	7	1
Purple	beamline	9	13
	design	18	19
	monochromator	8	10
	performance	10	9
	synchrotron radiation	7	5
	undulator	6	9

).

The first cluster (yellow) centers on the theme of electric vehicle systems and infrastructure. Key terms such as electric vehicle, hybrid electric vehicle, batteries, smart grid, and mobility suggest a strong concentration of research on the technological foundation of EVs. This includes battery technologies, grid integration, and the development of hybrid models, all critical for the mass adoption and operational efficiency of EVs. The connections to system and optimization indicate an engineering approach to improving power distribution and vehicle management systems, reflecting a convergence of automotive design and energy engineering.

The second cluster (red) offers critical insights into the socio-environmental dimensions of electric vehicle integration within the context of urban tourism and smart city development. Centered on keywords such as adoption, attitudes, behavior, charging infrastructure, CO₂ emissions, mobility, policy, renewable energy, and sustainability tourism, this cluster underscores the interplay between user perspectives, environmental concerns, and infrastructural readiness. The inclusion of adoption, attitudes, and behavior points to growing scholarly attention on how public perception and individual decision-making influence the uptake of EV technologies—especially among tourists and city dwellers. Meanwhile, charging infrastructure emerges as a fundamental enabler of sustainable mobility, particularly in areas with high tourist density where seamless and visible access to EV charging is essential. Environmental sustainability is strongly reinforced through the linkage between CO₂ emissions, renewable energy, and policy, suggesting that many studies explore how regulatory frameworks and clean energy transitions shape the deployment and effectiveness of electric vehicle systems. The term sustainability tourism highlights the evolving discourse on how green transportation methods, such as EV-based tour buses or rental fleets, contribute to more responsible travel behavior and destination management in smart urban environments. Overall, this cluster encapsulates the essential human, environmental, and governance factors driving the shift toward greener, more adaptive urban tourism experiences.

In the third cluster (green), the emphasis is on optimization, system design, and performance enhancement. Terms such as optimization, design, system, strategy, impact, and performance signal research efforts directed at improving EV functionality and energy system performance through design innovations and strategic modeling. This cluster connects closely with Clusters 1 and 2, bridging the technical aspects of EVs with policy-driven and behavioral outcomes. It reflects the integration of advanced computational techniques and systems engineering to enhance reliability, stability, and sustainability in energy and mobility systems.

The fourth cluster (blue) represents a technical and materials-focused dimension within the broader landscape of electric vehicle and smart city research, emphasizing advanced semiconductor and nanomaterial technologies that underpin sustainable infrastructure. Comprising keywords such as doping, GaN, growth, MBE (Molecular Beam Epitaxy), MOCVD (Metal–Organic Chemical Vapor Deposition), MOVPE (Metal–Organic Vapor Phase Epitaxy), structure, and ZnO, this cluster highlights intensive research into the development of high-performance electronic materials essential for energy-efficient systems. GaN (gallium nitride) and ZnO (zinc oxide) are frequently studied due to their superior electrical properties, which are crucial for power electronics, fast-charging systems, and sensor applications in electric vehicles and smart urban infrastructures. Techniques such as doping are explored to enhance material conductivity and performance, while growth refers to the controlled fabrication of these materials using methods like MBE, MOCVD, and MOVPE. These processes are vital for achieving the precise structure and purity needed in semiconductor devices. As smart cities increasingly rely on miniaturized, high-efficiency electronic components to manage mobility networks, energy systems, and data flows, the innovations within this cluster form a foundational layer for advancing both electric vehicle technologies and the broader intelligent urban ecosystem.

The fifth cluster (Light blue) centers on technological innovation in energy transfer systems and diagnostic tools, with a particular emphasis on enhancing the efficiency and practicality of electric vehicle (EV) infrastructure in smart cities. Keywords such as high efficiency, inductive power transfer, wireless charging, and wireless power transfer highlight the growing research focus on contactless energy delivery systems. These technologies are integral to the development of user-friendly, low-maintenance charging solutions that can be seamlessly embedded into urban environments, such as roads, parking lots, and public transit stations. Inductive power transfer and wireless charging not only reduce the physical footprint of traditional charging stations but also improve energy transfer efficiency and support real-time mobility needs. Additionally, this cluster includes advanced analytical tools such as spectroscopy and X-rays, which play a critical role in the material characterization and performance optimization of components used in wireless power systems. These techniques allow for precise evaluation of material behavior and system integrity under various operational conditions. Collectively, the purple cluster underscores a pivotal research avenue aimed at elevating the technical sophistication and convenience of EV infrastructure, thereby contributing to the larger vision of sustainable, smart urban mobility.

Lastly, the purple cluster concentrates on advanced instrumentation and beamline technologies essential for materials characterization and energy systems research, particularly in the context of sustainable mobility innovations. Central to this cluster are terms such as beamline, design, monochromator, performance, synchrotron radiation, and undulator, all of which point to the sophisticated experimental setups used in synchrotron facilities. These tools are instrumental for investigating the structural, electronic, and chemical properties of materials used in electric vehicles (EVs) and charging infrastructure. Synchrotron radiation and undulator sources offer highly focused, tunable beams that enable precise measurements and in-depth analyses of material performance under realistic conditions. The monochromator plays a critical role in isolating specific wavelengths for targeted experiments, enhancing the performance and accuracy of material diagnostics. Emphasis on design reflects ongoing efforts to optimize these complex systems for greater efficiency and resolution. This cluster highlights how high-end analytical techniques contribute to innovation in smart city mobility by supporting the development of high-performance materials and energy systems integral to EV and urban tourism infrastructure.

The co-occurrence map reflects a diverse yet interconnected body of research that supports the vision of electric vehicles as integral to sustainable urban tourism in smart cities. Each cluster contributes a unique perspective, ranging from infrastructure and user adoption to system optimization and technological innovation, offering a comprehensive understanding of how EVs can facilitate greener, more efficient, and tourist-friendly urban environments.

Although the introduction notes the relevance of electric buses, e-bikes, and e-scooters, these terms appeared with very low frequency in the dataset (<2%). This suggests limited bibliometric visibility, highlighting a research gap in sustainable tourist mobility that future studies should address.

4.6. Overlay Visualization

The overlay visualization provides a rich bibliometric analysis of the relationship between electric vehicles (EVs) and urban tourism in smart cities, focusing on sustainable mobility trends and infrastructure development (Figure 6). The key elements observed in the visualization can be broken down into several critical themes.

The term “electric vehicle” is prominently positioned as the central node, indicating its significance in the discourse on sustainable urban mobility. Its connections to various other topics highlight its multifaceted role in both transportation and tourism. Related concepts such as battery management systems connect directly to electric vehicles, pointing to the technological underpinnings necessary for efficient EV use. Additionally, the node for sustainable tourism suggests a growing interest in how EVs can support eco-friendly travel practices within urban settings. The connection to smart infrastructure indicates ongoing research into how cities can adapt their frameworks to support EV integration.

The visualization likely captures data from 2016 to 2024, showing the evolution of research focus over these years. In the early years (2016–2018), initial studies may have centered around foundational technologies like battery management and efficiency. As the timeline progresses into the mid-years (2019–2021), a shift towards optimizing charging systems and integrating EVs into urban settings likely occurred, reflecting the increasing importance of infrastructure. In the most recent years (2022–2024), there appears to be an emphasis on sustainability and tourism, indicating a recognition of the need for eco-friendly travel solutions in urban areas.

The color gradient in the visualization represents the years, with darker colors indicating more recent research. This highlights the rising interest in sustainable mobility solutions. Node sizes also play a role, as larger nodes signify more frequent mentions or greater relevance in publications, indicating the importance of particular topics over time.

The strong links between electric vehicles, battery technology, and infrastructure development suggest a holistic approach to solving urban mobility issues. This interconnectedness is crucial for developing effective policies and practices in smart cities. Additionally, the rising prominence of sustainability and tourism in the context of EVs reflects a broader societal shift towards environmentally conscious travel. This trend is essential for urban planners and policymakers aiming to enhance the appeal of cities while reducing carbon footprints.

Given the trends observed, future research could delve deeper into the socio-economic impacts of integrating EVs in urban tourism. Exploring user behavior, public policy implications, and the role of technology in facilitating sustainable tourism could provide valuable insights.

The separation between ‘electric vehicle’ and ‘electric vehicles’ in Figure 6 results from tokenization during co-occurrence analysis. Both terms were interpreted as a single concept in the discussion to avoid duplication. The overlay visualization effectively illustrates the dynamic interplay between electric vehicles and urban tourism within the context of smart cities. As research continues to evolve, maintaining a focus on sustainability and infrastructure development will be pivotal in shaping the future of urban mobility. Further interdisciplinary studies are encouraged to leverage the benefits of electric vehicles in enhancing urban tourism experiences.

5. Conclusions

This study provides a comprehensive bibliometric mapping of 593 publications and introduces two core innovations: (1) an integrative framework connecting EV trends, urban tourism, and smart city systems; (2) a cluster-based visualization overlaying infrastructure and tourism dynamics for actionable insights.

Building upon the empirical and bibliometric analyses, this study offers two core innovations. First, it presents a novel integrative framework that synthesizes bibliometric insights on EV trends with urban tourism dynamics within smart city infrastructures. This integrative lens uncovers cross-disciplinary thematic clusters—spanning policy, technology, and IoT connectivity—not previously mapped in the existing literature. Second, it introduces a thematic-clustered visualization approach that goes beyond traditional keyword co-occurrence by overlaying mobility infrastructure variables and tourism hotspots, thereby creating an actionable knowledge map for practitioners.

The relevance of human–machine integration paradigms (e.g., the human–machine interactive reinforcement learning using PPO) underscores the value of melding human-centered and system-driven methods. While our review is biblio-metric in nature, drawing inspiration from such reinforcement learning frameworks supports how future methodologies might incorporate both automated trend detection and expert-driven validation when planning sustainable mobility interventions in urban tourism environments.

In sum, this study not only consolidates cross-domain developments between EV technology and tourism, but also charts a methodological path forward: researchers and policymakers can leverage this dual-perspective mapping to design responsive and context-aware EV infrastructure strategies tailored to tourism demand in smart cities.

The Red Cluster focuses on adoption behavior, public attitudes, charging infrastructure, CO₂ emissions, policy, and renewable energy—highlighting sustainability’s role in urban tourism and EV integration. The Blue Cluster covers material science innovations, particularly doping, GaN, ZnO, and crystal growth methods critical to efficient EV components. The Green Cluster centers on energy systems and smart grid integration, while the Yellow Cluster emphasizes mobility data, V2G technologies, and digital forecasting tools. The Purple Cluster deals with beamline design, synchrotron radiation, and system diagnostics, and the Light Blue Cluster explores wireless communication, automation, and battery management.

Engineering and physics dominate the research fields, with strong alignment to UN SDGs 7, 11, and 13. High-impact studies point to innovation in charging systems, energy efficiency, and infrastructure optimization.

The findings demonstrate growing global attention to sustainable urban mobility. Advancing EV use in smart cities requires continued interdisciplinary collaboration that integrates technology, policy, and urban planning for a greener and more connected future.

This study is limited by its reliance on data from the Web of Science database, which may exclude relevant publications indexed elsewhere. The analysis primarily captures quantitative patterns and cannot fully account for the qualitative depth or practical impacts of the studies reviewed. Additionally, bibliometric tools may overlook recent emerging trends due to citation lags.

Future research should expand to include other databases such as Scopus and IEEE Xplore to provide a more comprehensive view. There is also a need for qualitative meta-analyses to explore contextual factors influencing EV adoption in tourism-oriented smart cities. Emerging topics such as AI-driven traffic management, user-centric mobility platforms, and cross-sector policy integration offer rich directions for future exploration. Interdisciplinary studies linking behavioral science, infrastructure design, and policy innovation will be crucial in advancing sustainable mobility solutions globally.