1. Introduction
Globally, urban centers, especially those in Europe, are experiencing population growth pressure, obsolete infrastructures, and climate change vulnerability which have culminated in the need for advancements in the management of cities [
1,
2]. Some of the challenges that arise as a result of urbanization include traffic congestion, solid waste management, energy utilization, and environmental concerns [
3,
4,
5]. In response, many cities are adopting smart technologies—AI and digital twin technology—as the leading innovations for the introduction of advanced urban governance and planning [
6,
7].
Real-life city models or digital twins (DTs) are a relatively new yet powerful concept that enable scientists and policymakers to experiment with physical environments in a simulated environment that replicates a city [
8,
9]. Across the world, the use of digital twin technology is gradually increasing as governments work towards sustainability objectives, for instance in building smart and resilient cities [
10,
11]. Currently, cities such as Helsinki and Amsterdam are using the digital twin model, and the recorded outcomes demonstrate the efficiency of spatial twins in urban planning [
12,
13]. Nevertheless, there is still a lack of attention towards the effectiveness of incorporating digital twins for predictive urban planning while analyzing the practical outcomes of unique digital twin characteristics in real contexts [
14,
15,
16].
Regionally, Europe is ahead regarding the adoption of AI and digital twin technologies to make cities more resilient, sustainable, and smarter [
17,
18]. Many cities in Europe consider digital twins as revolutionary tools for the better management of cities, although an apparent lack of knowledge about the functions that have the most significant impact on urban planning still exists [
19,
20]. In this context, it is essential to assess the correlation between the features of digital twins and the urban planning outcomes, especially as cities such as Athens and Thessaloniki are starting to consider the adoption of digital twin technology [
3,
12].
In the local setting, Greece is a quintessential candidate for the adoption of digital twin technology aimed at addressing the issues of urban transformation, protection of cultural heritage, and resilience to climate change because it is grappling with issues inherent to coastal megacities [
3,
21]. As Greece implements smart city practices across its population, this paper focuses upon Greece, and more specifically Athens, to evaluate the efficiency of digital twin systems within the prospective urban planning [
12,
18]. Focusing solely on Greece, this paper seeks to address the aforementioned gap by presenting empirical findings about the performance of digital twins in enhancing urban planning through simulation fidelity, real-time data integration, AI analysis, and system usability as evidenced by the interactions within the end user interface [
15,
22].
To be precise, the concept of system readiness implies the ability of digital twin systems to be effectively deployed and operated in an urban environment. Some of these factors include the infrastructure compatibility, the availability of data, and the technical ability of the system and the users. Indicators used to measure the aptitude of the systems include the system stability, benchmarking of performance, and the comfort and familiarity of the user with the technology. These indicators assist in finding out whether the digital twin system is functional and in a position to support urban planning processes [
19,
20].
Thus, the present study is crucial to advance knowledge regarding the application of the digital twin systems to improve the predictability and resilience of the urban planning of smart cities in Europe with an emphasis on Greece [
20,
23]. Thus, this study will enhance the understanding of the effects of specific DT functionalities and complement the existing body of literature on smart cities; it will provide valuable best practices and guidelines for city planners and policymakers who are considering the use of AI integrated technology in their cities.
1.1. Problem Statement
The rising population density, complexity of infrastructures, and dynamics that characterize most modern cities have put a lot of pressure and strain on existing conventional urban planning procedures [
24,
25]. Consequently, cities across the globe have begun adopting smart infrastructure technologies with a special emphasis on artificial intelligence-based digital twin solutions for planning and decision making. A digital twin is the creation of an actual model of a city with data streams, simulations, and analytics for modeling and forecasting urbanization processes, further management, and planning [
7,
8].
Nevertheless, there is still a lack of knowledge about which aspects of the digital twin systems directly help to improve the efficiency of the prediction of urban development. Even though currently cities like Helsinki and Amsterdam are implementing the use of digital twins, there are a lack of case studies to support the application of such systems in urban planning. In reviewing the existing research, we also noted that prior work relied on conceptual models or specific case studies, which are not as statistically valid or generalizable to other urban environments, as these studies by Bibri et al. [
26] and Evangelou et al. [
3] demonstrate.
Consequently, studies have not been able to identify which key characteristics, including accurate simulation, real-time data integration capability, the artificial intelligence-based analytics feature, maturity level, and the user interface interactivity feature, most significantly contribute to the enhanced results of urban planning [
27,
28,
29].
This gap has resulted in cities adopting and developing complex digital twin systems; however, it is not known which aspects will have the biggest positive impact on the overall performance of the prediction models. This prevents the municipal authorities from improving urban planning and management, ensuring resource optimization, and avoiding poor decision-making using the developed digital twin functionalities. This study thus seeks to address this research gap by assessing the features of digital twins that offer the most optimized outcomes for predictable urban planning, especially in the European region, including Greece.
Greece was specifically chosen due to its unique urban challenges, including coastal vulnerabilities, rapid urbanization, and significant pressure on the infrastructure. These challenges make Greece an ideal case for examining the potential of AI-driven digital twin technologies in predictive urban planning.
1.2. Purpose of the Study
The goal of this research is to assess the effectiveness of using AI digital twin technology as a tool for improving predictive urban planning in several smart cities in Europe with an emphasis on Greece. European cities are now battling issues including increased urbanization, climate change, and the management of infrastructure, and hence there is a need to adopt advanced technologies which enable the simulation, analysis, and forecasting of the urban environment.
1.3. Research Objectives
The purpose of this study is to identify how some of the key attributes of digital twin technology impact the predictive urban planning capabilities within different smart cities in Europe. Specifically:
To evaluate the impact of increased fidelity on simulation and the impact of simulation on the ability to predict urban planning.
To assess how real-time data integration affects the effectiveness of predictive urban planning.
To examine the correlation, if any, between the use of AI-based analytics and the efficiency of predictive urban planning.
To assess how system maturity affects the ability of predictive urban planning to achieve its aims.
1.4. Research Hypotheses
Hypothesis 1 (H1). There is a positive relationship between the simulation fidelity level of digital twins and the effectiveness of predictive urban planning.
Hypothesis 2 (H2). Real-time data integration highly improves the effectiveness of predictive urban planning.
Hypothesis 3 (H3). AI introduced into digital twins augments the efficiency of predictive urban planning.
Hypothesis 4 (H4). There is a positive association between the system maturity of digital twins and the effectiveness of predictive urban planning.
3. Methodology
3.1. Research Design
This study used a cross-sectional quantitative research approach to compare the various features of digital twins for predictive urban planning in the context of smart cities in Europe with an emphasis on Greece. The purpose of this study was to develop metrics to assess the level of simulation fidelity, real-time data integration, artificial intelligence capable of supporting decision making, system maturity, and the level of user interface interactivity that are directly correlated with the overall level of effective predictive urban planning. A structured questionnaire was used as the main data collection tool in this study. It was cross-sectional in its design, which allowed the researchers to capture the participants’ current beliefs concerning DTs and their relevance to urban planning.
3.2. Target Population, Sample Size Determination, and Sampling
This study involved urban planners, data scientists, and digital infrastructure managers in smart cities in Greece as the target population. Experts in these particular fields were selected because of their direct work in implementing, operating, and managing digital twin systems in urban planning. The participation of these hands-on individuals will ensure that the feasibility and difficulties of utilizing digital twin technology in urban environments are fully explored. With the orientation of such professionals, the study will document the insights of individuals with both technical expertise and practical knowledge in the urban planning and digital infrastructure industry.
The size of the targeted sample in this study was estimated using the Krejcie and Morgan [
72] sample size estimation
Table 1 that is commonly utilized in survey-based studies. The sample size was estimated as 301 respondents, based on an estimated population of 1350 urban professionals employed in the operation of digital twin systems within Greek smart cities. This sample size was evaluated as being adequate to provide sufficient statistical power and representativeness for drawing trustworthy conclusions from the sample data based on the survey. A bigger sample size would also mean that the data gathered would be strong enough to provide useful inferential analysis.
Purposive sampling was used to choose the respondents. This sampling method was particularly selected since it will involve the sampling of individuals with relevant knowledge and experience in the field of study. The purposive sampling will guarantee that the sample participants have direct experience in managing and implementing digital twin systems; thus, they can offer more insights into the difficulties, advantages, and practical uses of the systems. This sample selection method is frequently applied in studies that demand a level of expertise or special knowledge since this method guarantees that the information obtained is most relevant and resourceful.
Equation (1) shows the equation of Krejcie and Morgan.
where:
n = sample size
N = population size (1350)
χ2 = Chi-square for specified confidence level at 1 degree of freedom (3.841)
d = desired margin of error (expressed as a portion = 0.05)
P = population portion (0.05)
3.3. Data Collection Instrument
The survey tool used in this research was a self-administered, 30-item scale using Likert-type questions. Based on these items, six factors were derived; five independent factors: simulation fidelity, integrated real-time data, artificial intelligence analytics, system maturity, and user interface interactivity; and one dependent factor: predictive urban planning effectiveness.
Before administering the questionnaire, the questionnaire underwent expert validation by three urban planning and data science specialists prior to data collection to ensure content validity. The items were reviewed in terms of clarity, relevance, and congruency with research objectives by the three specialists in urban planning and data science. They provided their responses that were considered to improve the questionnaire so that it could comprehensively capture the key information concerning digital twin technology in urban plans.
Most of the identified items had been developed through previous studies in digital twin systems and smart cities meaning the focus of the study was indeed well-anchored on previous studies. On the survey questionnaire, responses were based on a five point Likert scale where 1 = strongly disagree and 5 = strongly agree. This scale ensured that the perceptions of the respondents were measurable with a degree of uniformity, thus improving the credibility of the data obtained. Further reliability tests were also undertaken to determine the questionnaire’s consistency and strength before administering it to the respondents.
3.4. Operationalization of Variables
The key variables were measured or operationalized as follows:
Independent Variables (IVs):
Simulation Fidelity: Defined as the extent to which simulation models are able to capture the realistic modes of urban conditions.
Real-Time Data Integration: Assessed based on how the live data inputs affect the planning forecasts.
AI-Based Analytics: Measured by the extent to which machine learning enhances the set-up of the scenario analyses.
System Maturity: Assessed on whether the regular practice of digital twin systems over time increases its forecasting effectiveness.
Dependent Variable (DV):
Predictive Urban Planning Effectiveness: This is the extent to which the technological manipulation of digital twin systems affects the overall effectiveness of urban planning decisions or recommendations.
3.5. Data Analysis
Data analysis was conducted using descriptive and inferential statistical analyses. A brief description of the collected data outlined the age, gender, and experience of the respondents, as well as their position within the field of urban planning. To measure the degree of the positive or negative relationship between the independent and dependent variables, the Pearson coefficient was used. Also, a multiple linear regression analysis was carried out to determine the significance of the hypothesized relationships between the four independent variables (digital twin features) and the dependent variable (the effectiveness of predictive urban planning). Each statistical test used an alpha level of significance set at 0.05. The analysis of predictive variance in urban planning effectiveness involved the use of regression analysis whereby the independent variables were used to explain the result. The proposed multiple regression model for this research is Equation (2) [
73,
74].
where:
Y is the predictive urban planning effectiveness, which assesses the general efficiency of digital twin systems in enhancing urban planning accuracy and productivity.
X1 = is the simulation fidelity (the first independent variable, IV), which reflects the capability of simulation models to accurately mimic the real environment.
X2 = represents real-time data integration, which studies how the data collected from the sensors installed in cities affects the forecasting and planning of scenarios.
X3 = represents AI-based analytics, which refers to the role of machine learning in enhancing predictive analysis and scenario planning.
X4 = represents system maturity indicating the effectiveness of the digital twin system based on its age and the experience of the team and programmers involved in implementing the system.
β0 = is the intercept of the model.
ε = represents the error term in the multiple regression model.
This model was used to test the amount of variance in the predictive urban planning effectiveness explained by the five independent variables (IVs). The assumptions of multiple regression such as normal assumption, linearity, multicollinearity, and homoscedasticity were tested and met as a condition of the analysis to be valid. The coefficients (β1, β2, β3, and β4) were estimated to provide an indication of the pathways of causality between the four IVs and the dependent variable. The hypotheses of the study were tested at the 5% (0.05) level of significance throughout the study.
3.6. Ethical Considerations
The rights of the participants were respected, and the following guidelines of ethical issues were considered: All the respondents provided informed consent and were informed that they were free to participate in the study without influence and could opt out of the study at any time. The data collected in this study were strictly used for academic purposes and stored in a secure manner to avoid identification of the individuals involved.
3.7. Limitations of the Study
The limitations of this study entail matters concerning sample representativeness and questionnaire design. The use of 301 respondents as the sample size was informed by the recommendations of Krejcie and Morgan, although the sample was limited to practitioners in Greek smart cities, which may influence the overall results as urban planners, data scientists, and managers in Europe could be more varied in their implementation strategies. Thus, one should not assume that the results obtained from Greece can be applied to other European smart cities, as they differ in their levels of urbanization, the penetration of a digital twin, and policies. Also, some sources for the scales used were not reported in their entirety; only the reliability and validity analyses of this questionnaire were mentioned. A lesser discussion around the importance of the reliability and validity of the scales used would make the study more transparent. These details could aid in providing a better insight into how the questionnaire might be applicable in various urban situations and enhance the authenticity of the results.
4. Results
This section presents the results obtained after analyzing the data collected from the selected respondents.
4.1. Demographic Characteristics
Table 2 presents the demographic profile of the respondents. There were 301 participants in the survey; their details are captured in the following table based on age, gender, professional role, and years of experience in using digital twin technology in urban planning.
The data results in
Table 2 showed that 301 participants responded, of which 60.8% had worked for 26–45 years, which indicates that the workforce is young and has exploitative experience. This age group implies that the majority of the respondents are likely to be mid-career employees with considerable working experience but who continue to learn and update themselves, given the dynamic nature of digital twin technology. Regarding the gender distribution, 62.8% of the respondents were male while 37.2% were female, which is quite common in the fields of technology and urban planning.
At present, the largest group of respondents occupies professional positions related to planning (45.8%), followed by digital infrastructures (28.3%), and data scientists (25.9%). From this distribution, it indicates that the survey received input from a good mix of professionals who actively engage in the use of digital twin technologies in urban planning. A majority of the respondents, 59.1%, had between 6 and 15 years of experience as city planners; this means that the sample had high and adequate levels of experience in the urban planning and digital twin systems which can be used to inform the viability of using advanced technologies in predictive city planning.
4.2. Simulation Fidelity and Predictive Urban Planning Effectiveness
This study assessed the impact of high-fidelity and low-fidelity simulations on predictive planning for urban areas. These are depicted in
Figure 1, with participants required to indicate the extent to which they agree or disagree with statements about the accuracy and efficiency of the simulation models used in urban planning.
Figure 1 shows that the respondents have a positive perspective concerning the utilization of high-fidelity simulation models within the sphere of urban planning. This study showed that 95% of the respondents were either rather likely or highly likely to participate in future surveys, demonstrating future participation willingness and a reinforcement of the survey results. Similarly, 72% of the respondents acknowledged that the simulation models are accurate in their general forecasting of urban development needs and probabilities, thus stressing the reliability of the models.
Regarding the extent to which simulation fidelity is considered as having a direct influence on the efficiency of urban planning, 18 individuals agreed or strongly agreed with this notion, which shows the significant role that model realism plays in the overall performance of planning activities. In addition, 75.7% of the respondents agreed that there is a direct relationship between the quality of the simulation models developed and the level of accuracy of the plans made, further reiterating the belief that great simulation models yield better planning decisions. Collectively, the findings imply that the respondents believe that high-fidelity simulation is critical in increasing predictive urban planning. This underlines the significance of providing urban development strategies that employ accurate and reliable simulations for the planning and design of better cities, with the majority of respondents expressing their trust in the use of digital twins for urban planning.
4.3. Real-Time Data Integration and Predictive Urban Planning Effectiveness
The second research question in the study sought to assess the impact of real-time data integration on the effectiveness of predictive urban planning.
Table 3 below shows the responses from the participants regarding their perception of the importance of live data in improving the forecast of urban dynamics.
Table 3 above shows that real-time data integration is crucial to enhance the efficiency of predictive urban planning. The necessity and importance of real-time data integration can be highlighted in particular with reference to the respondents’ perception of assistant real-time data integration, where 80.1% of the respondents agreed or strongly agreed with the statement that it makes a significant contribution to the planning forecasts. Likewise, 75.7% of the participants stated that adopting a live data integration method enhances the credibility of urban planning information, indicating its usefulness. In addition, 77% of the respondents pointed to the idea that the real-time data assists in decision making; this supports the notion that real-time data helps the planners to make more sound decisions.
This is apparent based on the 71.9% of respondents who opined that incorporating real-time data helps in envisaging the future trends in urbanization. Moreover, 77.4% of the participants opined that the employment of real-time data enhances the efficiency of urban planning, thus enhancing the emergence. Concerning real-time data in the context of urban forecasts and planning, 76.9% of the respondents agreed with this statement. In essence, 77.6% of the participants noted that live data integration has had a positive effect on predictive urban planning. Targeted surveys reveal that real-time data integration is received as a helpful tool with an acknowledged contribution to the accuracy, efficiency, and efficacy of urban planning, which gives confidence to smart city adoption.
4.4. AI-Based Analytics and Predictive Urban Planning Effectiveness
The third research question was to establish the impact of AI-based analytics on the performance of predictive urban planning. These findings are presented in
Figure 2.
According to
Figure 2, the perceptions towards the use of AI-based analytics for improving the predictability of urban planning are generally positive. The highest percentage of yes answers was received concerning the items that stated that AI analytics helped to enhance the projection precision of urban planning and refine the decision-making procedures by 75% to 80%. Also, 78.7% of the participants shared the opinion that with AI-based analytics, the predictive estimations of urban planning are more accurate, whereas 79.3% also approved of the concept of applying ML to digital twins to optimize urban planning. In addition, 78.3% said that AI analytics are crucial to identifying better future urban environments, and 77.5% said that using AI in digital twins helped to enhance the quality of urban planning decisions.
Indeed, such responses indicate that AI is viewed as useful in enhancing the credibility of urban planning through analysis. Specifically, 75.8% of the respondents considered that the use of AI-based predictive models has increased planning precision while 78.8% also asserted that AI analytics has increased the speed of urban planning and its responsiveness. This supports the argument that AI averts the time and effort needed in the planning process. Similarly, the research results indicate that AI-based analytics are considered ‘must-haves’ for enhancing the efficiency, efficacy, and velocity of the urban planning decision-making process and stress the relevance of AI solutions in contemporary smart city planning.
4.5. System Maturity and Predictive Urban Planning Effectiveness
This study also assessed the link between system maturity and the effectiveness of predictive urban planning. The results are presented in
Table 4.
In
Table 4, it is observed that 57% of the respondents agreed or strongly agreed with the statement that the maturity of digital twin systems enhances urban planning results. The current response indicates a certain understanding that the more advanced the digital twin systems are, the more useful they are in urban planning, providing more insights and predictions. Considering that more than half of the respondents shared this view indicates the perceived worth of a mature system on the process of urban decision-making. It is an indication of the general recognition that these systems are improving and that they will provide more dependable data, resulting in a subsequent increase in the quality and efficacy of urban planning decisions.
Moreover, 74.8% of the respondents reported that the maturity of the digital twin systems impacts positively on urban planning, with 35.5% completely agreeing. This affirms the unanimity that more established systems translate into better implementation of the urban planning procedures, and it implies that exposure to such technologies aids urban planners in refining their planning methods and forecasts. It may be concluded that the more the digital twin systems are utilized, the better they are at simulating the actual urban environments in a metropolis, and the more accurate the projections become on the development of the cities and their management. The active use of digital twin systems over a long period, based on the answers of 74.2% of the respondents, is also considered a method for increasing the accuracy of planning. These systems are able to develop knowledge and retain information over time, and as they become more experienced they can make more accurate predictions. The fact that 74.3% of the respondents feel that mature systems offer more predictability further substantiates the premise that systems evolve to become more accurate at predicting what is likely to happen in the city, along with population growth, traffic flows, and thus resource consumption. In addition, 74.4% of the interviewees contended that system maturity makes increasing predictions more precise, and 74.0% observed that the prolonged application of digital twins made the outcomes of planning improve. This gives all the more reason to bolster the assertion that the ongoing implementation and enhancement of digital twin systems are no longer just to optimize the quality of urban planning but also to elevate the precision of the urban forecasts. As time goes by, the system can be fed with the previous data to improve its algorithms and provide more accurate results.
The combination of these outcomes demonstrates that the maturity of the digital twin system is an essential factor in enhancing the efficacy of predictive urban planning. Advanced systems can process complicated datasets and combine multiple variables influencing urban spaces, giving decision-makers a more detailed and accurate understanding. The persistent utilization of digital twins over the years enables them to improve and change over time to thus better manage dynamic urban issues.
4.6. Diagnostic Tests
4.6.1. Normality Test
Multiple regression assumes the normality of the residuals, such that the residuals become normally distributed. The Shapiro–Wilk test was applied in this research to test the normal distribution hypothesis. The p-value obtained was 0.145 (
Table 5), which is greater than the significance level of 0.05 (p > 0.05). We thus do not reject the null hypothesis that the residuals are normally distributed. This signifies that the residuals comply with the normality condition, which is fundamental for the validity of the regression analysis.
4.6.2. Multicollinearity Test
To check for multicollinearity, the Variance Inflation Factor (VIF) was calculated for each independent variable (
Table 6). All the predictors of VIF were very low compared to the five threshold, meaning that no significant multicollinearity exists among the independent variables. This will affirm that the predictor variables do not overlap in their contributions to the model.
4.6.3. Test of Homoscedasticity
Homoscedasticity determines whether the variance in the residuals is homogeneous at every level of the independent variables. The Breusch–Pagan test was run to test heteroscedasticity (
Table 7). The p-value was 0.4732, which is greater than 0.05 (p > 0.05). Thus, we cannot disapprove of the null hypothesis of similarity in the error variance, meaning that the residuals are homoscedastic and the variance remains constant among the observations.
4.7. Regression Test
4.7.1. Fitness of Model
Table 8 displays an overview of the fitness of the model used in the regression analysis and assesses the extent of predictability of the dependent variable (predictive urban planning effectiveness) using the five independent variables: simulation fidelity, real-time data integration, AI-based analytics, and system maturity. This shows that it is possible to develop a well-fitted model that will capture the relevance of the digital twin technology features on the related city planning experience.
Furthermore, the obtained value of R = 0.829 suggests that the increased values of the independent variables are associated with the increased value of the dependent variable, thus showing that these predictors are impacting the predictive urban planning effectiveness. The obtained value of R2 = 0.688 indicates that 68.8% of the total variability in the measurement of the effectiveness of the use of predictive urban planning can be explained by the five independent variables. Therefore, this result validates the approach used in developing the model and supports our choice of the predictors that have the potential to capture the nature of variation in urban planning.
4.7.2. Regression of Coefficients
Table 9 shows the regression coefficients for each independent variable in the study. Here are the findings of the regression analysis test:
Practically, these results imply that enhancing the AI analytics capabilities yields the greatest incremental improvement in predictive urban planning effectiveness, followed by real-time data integration, simulation fidelity, and system maturity. These findings underscore the importance of leveraging AI and real-time data for more accurate and responsive urban planning processes.
Out of all the regression factors, AI-based analytics (0.382, p = 0.000) had the biggest impact on predictive urban planning in this particular regression analysis. This remarkable discovery suggests that AI analytics play a crucial role in improving the accuracy and the swiftness of urban planning decision making. The large value of the coefficient (0.382) indicates the power of AI to analyze large data, uncover concealed patterns, and create predictive models that enable real-time decision making. With the increasing complexity of city spaces, the ability of AI to integrate and analyze large volumes of data means that planners can make more accurate predictions, thus enhancing the effectiveness of the planning process. The statistical significance (p = 0.000) also supports the centrality of AI to predictive urban planning, indicating that it makes a deep impression in this respect.
The integration of data in real time (Β = 0.315, p = 0.001) is also an important factor in urban planning efficiency. Real-time data enables urban planners to change their approaches to suit the most up-to-date available information. This direct impact on the planning models emphasizes the significance of the availability of current data in order to make informed decisions. The significance (p = 0.001) suggests that real-time data plays a critical role in enhancing the accuracy and responsiveness of urban planning systems, indicating that we can accept hypothesis 2 (H2).
The coefficients of simulation fidelity include beta = 0.248 and p = 0.003. The obtained coefficients indicate that there is a strong positive correlation between the simulation fidelity and the effectiveness of predictive urban planning. Since the calculated p-value is less than the predetermined level of 0.05, we reject hypothesis 0 (H0) and accept hypothesis 1 (H1), which confirms that there is a positive relationship between the simulation fidelity and effective urban planning.
The beta result obtained for the system maturity is 0.289 and the p-value is 0.004. This means that a higher level of digital twin maturity is associated with enhanced effectiveness in urban plans, implying the acceptance of hypothesis 4 (H4). All the hypotheses are supported at a significant level by the regression test, displaying the contributions of all elements of digital twin technology in overcoming the deficits of predictive urban planning in smart cities.
5. Discussion
The purpose of this research was to investigate the effect of AI-based digital twin technology on predictive urban planning in Europe with an emphasis on selected smart cities in Greece. This study provides valuable information on how these technologies apply to improve the effectiveness of planning in urban settings by evaluating indices including the simulation fidelity, the integration of real-time data processing and AI-informed analytics, and the system maturity [
31,
48,
67].
Simulation realism is a critical determinant of the integrity of simulation-based models in urban planning. They accurately mimic real-life conditions, which makes it possible to predict future tendencies in urban processes like traffic movement, energy usage, and climate [
9,
31]. Regarding the specific benefits, this study also shows part B, where the majority of the respondents mentioned high-fidelity simulation as contributing to accurate urban planning. This is particularly complemented by the fact that the digital twin-based simulations of urban conditions as seen by the users are sensitive to the reliability of the underlying sources of information, and as the simulation fidelity increases, so does the effectiveness of the planning interventions for city management [
7,
8].
However, reaching high levels of simulation fidelity is not without its challenges. This is in line with the assertions of Sheraz et al. [
39] and Zong and Guan [
30] that while higher fidelity models are necessary due to the increasing complexity of urban systems, their simulation consumes a large amount of processing power and requires sophisticated algorithms. In line with these concerns, the respondents stated that as the systems become increasingly dynamic and integrated into the urban environments, the necessary simulation fidelity results in increased computational cost. The ability to achieve a balance between a precise simulation and a reasonable calculation time remains a crucial point in the effective application of digital twin technology in urban planning.
The use of real-time data is another influential factor that improves the flexibility of the models used in urban planning. Real-time data helps in decision making by allowing the planner to revise their plans in response to the current situation in the city, like traffic patterns, energy consumption, and weather, among others [
13,
25]. This research also supports previous theories indicating that the integration of real-time data in favor of urban planning is perceived to enhance accuracy and efficiency. The respondents noted that live data inputs not only make the forecasts more accurate but also offer the most current trends in urban areas [
7,
42].
Nevertheless, the approach of real-time integration also has certain drawbacks, the most critical of which are the handling of large amounts of data and quality and compatibility issues [
19,
23]. Maintaining the data integrity from several sources is also problematic due to the existing legacy structures and data interfaces that slow down the processing and utilization of real-time information, as this study shows. Similarly, data quality becomes a challenge whereby inadequate data quality impacts the performance of the planning models [
4,
43].
Machine learning is critical in improving the prognostication of digital twin models. AI also helps in giant dataset analysis for pattern exploration and is much more helpful for urban planning [
30,
31]. This research supports the use of AI in urban planning, since more than half of the participants agreed that it can assist in enhancing the accuracy of the forecast and decision making. According to Herath et al. [
20] and Rahman et al. [
34], the use of AI in analytics enhances the effectiveness of planning, making it more flexible to changes in the city environment. Nevertheless, as numerous authors assert [
13,
23], one major issue with AI analytics is the lack of transparency.
Claims that AI systems, particularly deep learning, are black boxes stems from the fact that it is not very clear how AI arrives at certain decisions. This can reduce confidence in the AI-driven advice as planners may not be able to comprehend the algorithms behind the forecasts, which slows the integration of AI technology into the urban policies [
55,
62]. To mitigate this problem, further advancements must be made in improving the explicability of the AI solutions and guaranteeing that the outcomes are clear to the planners and policymakers.
The safety and stability of the digital twin systems are critical in recognizing their effectiveness and ability to become an integral part of urban planning methodology [
19,
23]. Closely related to system maturity, the respondents noted that when organizations work with more mature digital twin systems, they will see better results in planning for cities. This was found to be the case, as many systems were found to become more reliable at predicting urban conditions as the system was used over time, benefiting from the experience of the planners. The maturity of the systems is a critical component of the credibility and success of digital twin technologies. The wider experience becomes the digital twin system, and the more likely the system is to predict the conditions in the city and offer valuable solutions to city planning. Our study found that mature systems yielded better results, as planners became more familiar with their capabilities over time [
3,
9]. Nonetheless, the system maturity involves considerable investment in infrastructure, training, as well as long-term upkeep. Many cities, especially those in developing regions, face challenges in maintaining and scaling their digital twin systems, which can affect the sustainability of these technologies [
49,
55]. Interoperability issues, particularly when integrating digital twins into existing urban planning processes, were also highlighted as key challenges [
6,
31]. This discovery highlights the need to create long-term programs to maintain, improve, and support digital twin systems so that cities can generate ongoing insights into digital twins [
75].
Still, the establishment of system maturity is a long-term and intricate process that calls for the commitment of substantial amounts of capital and personnel. It has also been revealed that many cities, especially the developing ones, experience difficulties in the maintenance, let alone scaling, of their digital twin systems, which can cause a problem with their sustainability [
49,
55]. Indeed, some studies have reported on the effects of system immaturity, primarily in regard to the integration of DTs into the urban planning processes, where interoperability problems emerge as a key challenge [
6,
31]. Therefore, one of the implications of this study is the importance of developing long-term initiatives to support, sustain, and upgrade the digital twin systems for cities.
Although this study provides clear evidence regarding the possible benefits of digital twin technologies, a number of challenges were observed. A major limitation to the effective utilization of such systems are the computational loads and data flow issues. The cities will face certain data quality, astronomical, and integration concerns as they upgrade to more advanced digital twins. The findings of this study highlight the importance of developing robust data management systems and establishing partnerships between data owners to facilitate seamless data integration [
31,
43]. In addition to this, the interpretation of the AI models and AI transparency play a crucial role in building confidence in AI applications. Addressing these concerns will be essential for incorporating AI-driven tools into urban governance and policymaking [
23,
62]. On the policy side, urban planners and policymakers need to also reflect on the ethical considerations of applying AI in urban planning, specifically the issues of data privacy and governance. The usage of AI-driven technologies creates some significant questions concerning who owns the data and how it is utilized. Making the process of AI decision making transparent will be central to building public trust and subsequently guarantee that the technologies will be used in a responsible and accountable way.
The findings of this study have several important implications for urban planners and policymakers: First, the simulation of fidelity, real-time integration of data, use of artificial intelligence analytical tools, and system maturity, all highly correlate with the success of urban planning outcomes, meaning that cities must adopt high-quality digital twin systems that comprise all these aspects. Such an approach suggests that the flow of information that accumulates in big cities should be matched with the predictive and real-time capabilities of AI technologies, so that policymakers are better able to support the solutions for urban issues [
3,
10].
Likewise, the study reveals that, for digital twin systems, issues like data integration and computational requirements should also be considered important. Cities must address the challenge of data fragmentation by embracing sound data management systems and building partnerships between the various data owners to incorporate real-time data into planning [
31,
43]. However, decision-making during AI-based analytics should be made more transparent to increase the trust in AI and incorporate AI-based tools into urban governance [
23,
62]. However, there are several limitations of this study that need to be noted. First, due to the use of cross-sectional data it would be difficult to draw causal conclusions regarding the association between the parameters of DT and the results of urban planning.
Longitudinal analysis would offer better evidence on the sustained effects of digital twin systems on urban planning. Second, since the study is based on the Greek context, the results may not pertain to all European cities, as there could be differences in the requirements of the urban environment, digital twin deployment, and region-specific policies. Further studies should be conducted, not only with a focus on multiple countries and cites but on the variation within countries in order to apply the results on a broader scale [
7,
19].
While the benefits of digital twin technology in predictive urban planning are evident, cities face significant challenges regarding their implementation. These challenges include infrastructural incompatibility, particularly in older cities with outdated systems, high computational demands when running complex simulations, and limitations in real-time data quality and integration. Overcoming these challenges will require substantial investment in infrastructure, the development of efficient data management strategies, and ensuring interoperability between different urban systems.
6. Conclusions
This study examined the role of the digital twin based on artificial intelligence to support and improve predictive urban planning in the context of smart cities, with an emphasis on Greek cities. By analyzing the key components of the digital twin system, such as the simulation centrality, integrated data feeds, AI analytics, and system sophistication, this study offers strategic insights into the potential of these technologies for advancing urban planning practices. The study has demonstrated that increasing the simulation of fidelity, the use of real-time data, and the incorporation of artificial intelligence improve the planning process in cities.
Firstly, the use of simulation fidelity enhances the accuracy of predicting the evolution of urban systems and structures. The use of real-time information enhances the ability of urban planners to make decisions that are informed by real-time information. Furthermore, AI-based analytics are useful in enhancing the rate and accuracy of prediction and decision making, which are essential in effective urban management. Another notable finding was the need to focus on the system maturity, as the usage and incremental improvement of the DT systems over a long-term period may translate into better planning outcomes and the ability to address the dynamic urban environment. This study also reveals some of the limitations of implementing digital twin systems in urban planning, in particular the requirement for significant computational power to achieve high levels of system realism, and the obstacles to handling time-sensitive information.
However, the lack of transparency was recognized as a major hurdle in developing trust and accepting the models. These issues show that there is a need for continuous investment in technology, staff development, and data management strategies to enhance the efficiency of the digital twins in cities. Considering the effectiveness of various features of the digital twin on urban planning, it is crucial that cities incorporate the following: adoption of advanced AI technologies, real-time data acquisitions, and system maturity. It is also crucial to focus on the improvement of the data-sharing standards and the regulation of AI transparency to make its usage more widespread. Altogether, this research extends the knowledge regarding smart city solutions and can be useful for those city managers and planners interested in adopting digital twin technologies to enhance the various aspects of urban environment functioning.