1. Introduction
Urbanisation and economic growth have led to a rapid increase in urban road traffic. The proliferation of private automobiles has placed significant strain on urban transportation systems, exacerbating ecological and societal challenges such as air contamination, roadway congestion, and vehicular collisions. China’s primary carbon-emitting industries include energy supply, manufacturing, construction, and transportation, with transportation alone accounting for approximately 10% of the nation’s total carbon emissions. As per the Ministry of Public Security, China had 435 million motor vehicles by 2023, with 336 million of them being automobiles. Additionally, 94 cities in the country have over 1 million automobiles [
1]. Therefore, regulating car travel is essential for reducing carbon emissions from transportation.
Since the 1970s and 1980s, the notion of sustainable development has progressively become prominent, including distinct meanings in numerous domains. Green transportation is an essential component for advancing the transportation industry within the sustainable development framework. Currently, green transportation is a popular and innovative approach to facilitate the transformation of urban transportation growth. Travel refers to the need for people to move from one place to another for a certain purpose or activity [
2]. Green travel, derived from green transportation, categorises travel behaviour according to the mode of transportation used. The focus is mostly on the notion of human-orientated behaviour, which refers to the deliberate actions taken by individuals to mitigate or address environmental issues through their transportation choices [
3]. The China Council for International Cooperation on Environment and Development (CICED) Policy Research Group defines green travel as a form of transportation that can substitute car travel and is appealing to various social strata groups. It is effective in mitigating urban traffic congestion and reducing air pollution. Green travel occurs continuously and has the potential to enhance the quality of the urban air environment, alleviate road congestion, and support the growth of urban public transportation systems. Furthermore, it can reduce the daily travel expenses of residents, promoting their overall health benefits. Hence, it is crucial to study green travel behaviour and investigate strategies to encourage such travel in order to preserve the urban environment and foster a healthy lifestyle.
A multitude of experts have performed extensive research on green travel behaviour, encompassing both its behavioural composition and interpretation. When discussing behavioural composition, green travel behaviour typically emphasises low-consumption and low-emission modes of transportation such as walking, cycling, using public buses, and taking the underground. Researchers commonly use indicators such as the origin points, modes of travel, routes, destinations, time, and costs to describe the characteristics of green travel. Regarding the interpretation of green travel behaviour, there are variations in the study of behaviour in the fields of psychology and behavioural sciences. As a result, theories have been developed from different perspectives to explain behaviour. Numerous studies have been conducted in relation to these theories. The theory of planned behaviour (TPB), developed by Professor Ajzen, has gained significant popularity in explaining human conduct because of its precise conceptual framework, standardised assessment methods, and strong explanatory capacity. This theory posits that behavioural willingness is influenced by three factors: personal attitudes, subjective norms, and perceived behavioural control, which in turn directly impact behaviour [
4]. Incorporating the traditional TPB theory, researcher Xuemei Fu introduced the concept of affective-cognitive consistency of attitudes as a moderator to examine the green travel behaviour of residents. The study revealed that the more pronounced the affective-cognitive consistency of attitudes, the greater the impact of attitudes on the willingness to engage in green travel [
5]. Unlike the theory of planned behaviour (TPB), the theory of interpersonal behaviour (TIB) developed by Harry integrates the influential factors of habit and emotion in explaining behaviours [
6]. On the other hand, the value–belief–norm theory (VBN) proposed by Stern elucidates the relationship between values, beliefs, and norms in understanding the environment [
7]. Hiratsuka et al. conducted a study in Japan to examine the validity of the VBN theory and found evidence supporting its ability to explain the decrease in car usage [
8]. Lewin’s intrinsic factor-external environment model posits that individual behaviours result from the interplay between the individual and their surroundings [
9], while Guagnano et al. introduced the A-B-C model (attitude–behaviour–context) for forecasting environmental behaviour [
10]. Song et al. applied the Stimulus–Organism–Response (S-O-R) theory to explore how environmental emotions mediate travel behaviours [
11]. Kaiser, Chen, Tongleta, and other scholars have highlighted that behavioural willingness refers to an individual’s psychological inclination and motivational drive prior to engaging in a specific behaviour. It is considered a crucial prerequisite for the actualisation of behaviours, with behavioural willingness being the primary determinant of behaviour occurrence. Furthermore, there exists a significant and positive correlation between the willingness to green travel and actual green travel behaviour [
12,
13,
14]. Therefore, the above studies often interpret green travel behaviour by examining behavioural willingness. It can be said that the research of green travel behaviour has transitioned from a singular understanding to various explanations and from focusing solely on individual factors to considering both internal and external factors.
Urban space, as an external context for human living, has a direct or indirect impact on human activities. Pikora and other scholars have examined the correlation between the environment and travel behaviours, such as walking and cycling, specifically in terms of the functionality, safety, aesthetics, and destinations of urban environments [
15]. Various urban development patterns can influence travel patterns, notably transit-orientated development (TOD), which reduces car dependency for non-work activities such as shopping by locating workplaces within TOD areas and promoting slower transport modes like walking [
16]. Researchers Rodríguez and Joo conducted a study to examine how pavements and the frequency of bus service influence the travel mode choices of inhabitants [
17]. Cervero highlighted that the arrangement of “compact neighbourhoods with a well-connected road network” promotes walking and cycling [
18]. Additionally, Schwanen and other researchers discovered that the thoughtful design of bus stops and comprehensive transportation infrastructure greatly influence residents’ choice of travel mode, favouring public transportation options [
19]. In conclusion, research has demonstrated that the urban environment has a substantial influence on the travel behaviour of individuals. Hence, urban planning is regarded as a pivotal strategy to encourage citizens to engage in walking, cycling, and utilising public transportation while discouraging reliance on motorised transportation [
20].
Research on the relationships between environmental factors and green travel willingness has traditionally focused on several key areas, such as the accessibility and quality of urban green spaces [
21], socio-economic influences [
22], individual attitudes [
23], and urban design [
24]. However, the issue is complex and involves the interplay of multiple factors, suggesting that a holistic approach is necessary. This research aims to integrate these diverse aspects, offering a comprehensive analysis that can inform effective urban planning strategies to promote green travel, particularly in challenging environments like winter climates.
In recent years, urban planning research related to green travel has expanded, increasingly focusing on the psychological and attitudinal factors that influence transportation mode choices. This body of work has also begun to integrate various urban environmental elements to better understand and enhance the green travel experience [
25]. Eva Heinen and colleagues, for instance, employed factor analysis to demonstrate the significant role of psychological factors in promoting cycling behaviour [
26]. De Vos’s study utilised structural equation modelling to analyse the behaviour of individuals engaging in walking and cycling in Ghent, Belgium, revealing that these active modes of transportation are associated with higher levels of satisfaction [
27]. Similarly, Kamargianni and colleagues found that satisfaction plays a crucial role in shaping travel preferences [
28]. In Lithuania, Audronė Minelgaitė and her team highlighted how long-term changes in pro-environmental behaviour, driven by environmental education and public initiatives, contribute positively to environmental awareness and conduct [
29]. Additionally, Bowei Zhong and colleagues explored the effects of travel time costs and feedback types on green travel behaviour, finding that environmental and health feedback can effectively encourage green travel when time costs are low [
30]. Collectively, these studies underscore the importance of considering individual psychological factors, societal contexts, and urban infrastructure when understanding and promoting green travel.
Despite significant advancements in science and technology, individuals are still unable to fully mitigate the adverse effects of climatic differences due to various factors, including socio-economic and geographical conditions, presenting critical challenges for urban planners. Statistics indicate that about 600 million individuals reside in frigid urban areas worldwide. According to Lu Xinchao and other researchers, winter cities are a distinct category of cities found in the northern hemisphere. These cities are characterised by their severe winters and harsh environment, with an average temperature in January below −18 °C [
31]. Construction circumstances in these regions are considerably more challenging in comparison to cities with milder climates, shorter building seasons, and extensive permafrost, resulting in increased construction challenges and decreased prospects for extensive development in specific areas.
Winter cities face unique challenges due to harsh climatic conditions, which complicate urban planning and the promotion of green travel. These challenges include physical barriers such as snow and ice, as well as the psychological impacts of long winters, leading to decreased public space usage and increased social isolation [
32]. Extreme cold significantly affects accessibility and livability, necessitating urban design that supports healthy lifestyles and social interactions [
33]. Effective climate-sensitive urban planning must integrate local topography and microclimatic conditions to enhance resilience and infrastructure efficiency [
34]. Infrastructure tailored for cold climates, such as well-designed subway stations, is essential to ensure safety, comfort, and increased public transit usage [
35]. However, green travel initiatives like public transport and cycling are often hindered by prolonged cold weather, leading to low resident satisfaction, underscoring the need for infrastructure updates that meet seasonal demands [
36]. Despite extensive research conducted since the 1980s by the Association of Winter Cities and various international campaigns, numerous thematic issues related to the impact of cold climates on urban development and design remain that require further in-depth discussion.
Promoting green transportation in winter cities poses greater challenges compared to other regions. However, winter cities have a more pressing need to reduce carbon emissions from transportation, as the combustion of fossil fuels for winter heating already places significant strain on the environment. Green travel is less popular in cold regions, particularly during winter, due to issues of comfort, convenience, and safety. While climate factors in these areas are immutable, enhancing the urban environment can facilitate and promote winter green travel. Despite this, existing research has yet to establish a comprehensive framework.
Using data from Shenyang, China, this study employs structural equation modelling (SEM) to investigate the impact of urban environments on residents’ willingness to engage in green travel in cities located in cold regions during winter. The study seeks to answer several key research questions:
What are the potential influencing factors on residents’ willingness to engage in green travel in cold-region cities during winter from an urban design perspective?
How can these potential factors be categorised into different dimensions that influence the willingness to engage in green travel?
What are the pathways through which these different dimensions impact residents’ willingness to engage in green travel, and how do they interact with each other, both directly and indirectly?
How do the influencing factors related to the urban environment exert a multifaceted on green travel willingness within this structured relationship?
This study innovatively introduces the stimulus–organism–response (S-O-R) theory to construct a structural equation model, examining the comprehensive interrelationships among the urban environment, residents’ attitudes and perceptions, and green travel willingness. By uncovering the influential patterns of travel willingness, this research provides theoretical insights and practical guidance for policymakers and urban planners to create urban environments that effectively encourage green travel behaviour among residents of winter cities during the winter season.
The subsequent sections of the paper are organised as follows:
Section 2 centres on our research technique, including the identification of potential influencing factors and the process of constructing the theoretical model. Additionally, it covers the construction, distribution, and processing of the questionnaire.
Section 3 presents the factor analysis results and structural equation modelling results.
Section 4 discusses the findings of the investigation, while
Section 5 provides a concise overview of the study.
2. Materials and Methods
The purpose of this study is to examine the relationships between urban environmental factors and green travel behaviours in winter climates. While correlation analysis and regression analysis are commonly used methods for such research, they often fall short in handling the complexity of multiple interacting variables [
37]. Structural equation modelling (SEM) offers significant advantages over these methods, particularly when dealing with complex relationships among variables. SEM’s ability to simultaneously model multiple dependent and independent variables, including latent constructs, allows for a comprehensive examination of direct, indirect, and mediating effects within a single framework [
38,
39]. This is more efficient than regression analysis, where each mediator requires a separate model. Moreover, SEM provides essential fit indices, such as chi-square, RMSEA, and CFI, ensuring that theoretical models align well with observed data, which is crucial for theory testing and refinement [
40]. SEM’s capacity to incorporate latent variables and test complex causal relationships makes it particularly powerful for developing and validating theoretical frameworks [
41].
In this study, SEM is particularly suited to exploring the complex relationships influencing green travel behaviors. It allows for modelling factors like priming and social influences, which activate latent environmental attitudes and shape sustainable travel practices, especially in winter contexts [
42]. Additionally, SEM captures the mediation and moderation effects of behaviour change processes, such as consciousness-raising and self-reevaluation, crucial for fostering green travel behaviours in challenging conditions [
43].
Furthermore, integrating the stimulus–organism–response (S-O-R) theory into SEM provides a robust framework for analysing how environmental factors act as stimuli that shape cognitive and emotional responses, ultimately influencing sustainable travel behaviours [
44,
45,
46]. This approach is particularly suitable to understanding green travel behaviours in winter climates, where the interplay of environmental stimuli and behavioural responses is complex and multifaceted.
2.1. Theoretical Model
The S-O-R theory posits that external environmental cues influence users’ reaction behaviour through subjective motivation and internal consciousness [
47]. This study examines the willingness to green travel as a response to the environmental conditions. Individuals with different characteristics may exhibit varying responses within the same environmental context, and conversely, an individual may have distinct responses in different environmental contexts. The process of individuals responding to the external environment is not immediate but rather involves personal judgement followed by a response. Judgement refers to an individual’s perception of the environment and their attitude towards it. The theoretical model depicted in the figure below (
Figure 1) can be developed as a foundation framework for investigating the various interconnections of green travel.
2.2. Potential Influencing Factors
The influencing factors of green travel vary in winter cities due to their unique weather characteristics. When studying winter cities, it is important to focus on the weather, climate conditions, and transportation aspects of these places. Chengxi Liu conducted a study using trip data of Swedish citizens and weather data modelling, revealing that weather factors have the most substantial influence among the various factors that affect travel [
48]. In a study conducted by Gössling et al. in Zanzibar, Tanzania, it was found that specific meteorological factors, such as rainfall, storms, and humidity, have a detrimental impact on travel choices [
49]. Similarly, in a study conducted by Meng et al., the researchers investigated the influence of weather conditions and weather forecasts on bicycle travel behaviour in Singapore, highlighting that cyclists were more inclined to alter their mode of transportation based on pre-rain weather forecast information [
50]. A study conducted by Ahmed et al. analysed the travel patterns of commuter cyclists in relation to variations in weather conditions, emphasising the influence of weather on the cyclists’ daily decisions on cycling [
51]. Consequently, we incorporated the inherent meteorological conditions of the city as a factor of influence. Urban areas in low-temperature circumstances necessitate additional cold protection measures. Therefore, we consider the spatial environment of waiting areas and connecting pathways as significant factors that determine the need for such measures. Mark J. Koetse conducted a study on the correlation between climate change, weather conditions, and transportation. Through a series of cases, he confirmed that climate change resulting from global warming and extreme weather events, such as high winds and snowstorms, had detrimental effects on both passenger and freight transport [
52]. Thus, fluctuations in transportation efficiency due to seasonal changes in winter cities might also influence the travel decisions made by inhabitants.
As shown in
Table A1 in
Appendix A, we compiled a comprehensive list of 34 observed variables by summarising prior studies and incorporating the unique characteristics of winter cities. While we did not introduce entirely new impact factors exclusively for cold cities, we have adapted and contextualised existing factors based on relevant literature and our disciplinary expertise. For example, factors such as natural greening, seasonal climate, path support, and the convenience of site connection, although not unique to cold cities, exhibit distinctive characteristics or attributes in these environments. This makes them particularly relevant and significant in the context of cold-region cities. There are 9 variables for evaluating travel perception, 6 variables for measuring attitude towards green travels, and 19 variables for assessing the external environment. These external environment variables consist of 13 variables related to the macro-urban environment and 6 variables related to the micro travel environment.
2.3. Questionnaire Design
The influence of subjective perceptions on subjective choice outcomes is well-grounded in established theories of behavioural science and cognitive psychology. For instance, the theory of planned behaviour (TPB) posits that individual attitudes and perceived behavioural control, both of which are subjective perceptions, significantly influence behavioural intentions and actions [
4]. Similarly, expectancy theory highlights the role of individual expectations and perceived outcomes in decision-making processes. Therefore, analysing the impact of subjective perceptions on subjective choices is both theoretically relevant and logically coherent [
53].
In this study, we focus on subjective perceptions as key variables influencing residents’ willingness to engage in green travel. This approach is based on the understanding that individuals’ subjective perceptions of their environment and the potential outcomes of their choices are critical determinants of their behaviour. By examining these perceptions, we aim to gain a deeper understanding of the factors that drive green travel decisions, particularly in the unique context of cold-region cities.
We designed a subjective questionnaire based on the listed observed variables to assess the evaluation of travel perception, attitude towards green travel, perception of the overall urban environment, and the perception of specific travel environments. Respondents were asked to rate a list of statements using a five-point Likert scale ranging from “Strongly Disagree” (1) to “Strongly Agree” (5) (
Table A2 in
Appendix A). Furthermore, we measure the willingness to green travel with ’Intention to travel green’, ’Planning to travel green’, and ’Recommending to travel green’ as the observed variables. Additionally, the questionnaire included a series of inquiries about demographic information such as gender, age, and household composition. A committee of specialists was established to thoroughly review the substance of the questionnaire via multiple iterations. Prior to administering the formal survey, a preliminary survey was undertaken to establish the reliability of the final questionnaire. We administered the initial survey questionnaires to individuals of various age groups in Shenyang City. Subsequently, we made revisions to the questions based on the feedback, resulting in the final version of the formal questionnaire.
2.4. Data Collection
We selected Shenyang, a representative city known for its frigid climate as the subject of our study. Shenyang, being a prominent city in the northeast region of China, is experiencing an influx of population from nearby cities, resulting in increased transportation demands. In the city core of Shenyang, the primary means of transportation include buses as the main method of transit, a metro network with five lines serving as the central transportation framework, and taxis providing additional support to meet the travel needs of city inhabitants. Nevertheless, challenges such as the suboptimal design of public transport stations, inadequate winter road safety measures, and unfavourable winter urban landscape all impede the progress of green travel.
As shown in
Figure 2, we selected seven locations within the central city of Shenyang based on high pedestrian flow and diverse population composition. Our research started on 23 November and ended on 26 December, a total of seven times. On average, each survey takes five hours. These locations are situated within different municipal districts: Heping District, Dadong District, Huanggu District, Tiexi District, Shenhe District, Sujiatun District, and Hunnan District. The chosen sites encompass a variety of busy areas such as shopping malls, parks, and markets. It is important to note that the data collection was conducted in specific locations within the central city of Shenyang and was not randomised across the entire population. As such, the data may not fully represent the broader population of Shenyang and should be viewed as illustrative rather than definitive.
To ensure the statistical validity of our study, we determined the appropriate sample size using the Raosoft sample size calculator (Raosoft, Inc.: Seattle, WA, USA) (
http://www.raosoft.com/samplesize.html, accessed on 16 July 2024). Given the population size of 7,620,000 for the urban area of Shenyang and the margin of error of 5%, the recommended sample size is 271 for a 90% confidence level and 384 for a 95% confidence level. After eliminating invalid questions, a total of 306 valid questionnaires were gathered, which exceeds the recommended sample size for a 90% confidence level. Although this does not fully meet the requirement for a 95% confidence level, the sample size is still statistically sound and supports the robustness of our findings within the scope of this research.
2.5. Data Analysis Method
Our primary data analysis method is structural equation modelling (SEM), which is effective in evaluating the connection between endogenous and exogenous latent variables [
54]. SEM also allows for the analysis of relationships between multiple independent and dependent variables, making it a crucial analytical tool in social science research. SEM comprises two components: the measurement model and the structural model. The measurement model represents the causal relationship between latent variables and their measures and is frequently employed to ascertain the relative importance of each indicator. The structural model is sensitive to the causal relationships between the variables. We utilised exploratory factor analysis to ascertain the number of factors associated with the observed variables. Subsequently, we developed the chained multiple mediation effect model, drawing upon the S-O-R theory. The model’s validity is assessed by confirmatory factor analysis and further refined and processed to ultimately determine the influence link between each variable.
2.6. Addressing Potential Endogeneity
In addressing the potential endogeneity of subjective perceptions influencing green travel willingness, we recognise the risks posed by factors such as omitted variables, measurement error, or reverse causality. To mitigate these concerns and ensure the robustness of our findings, we conducted exclusion tests, systematically removing variables to verify the stability of the results [
55]. Additionally, within the SEM framework, we accounted for measurement errors by explicitly modelling latent variables, a process that helps to alleviate some endogeneity issues. Where feasible, we also explored the application of instrumental variables (IVs) to reinforce the causal interpretation of our model [
56], although this approach is inherently more challenging within SEM. These methodological steps collectively provide a more accurate estimation of the relationships between subjective perceptions and green travel willingness, thereby enhancing the reliability and validity of our conclusions.
4. Discussion
4.1. Interpretation of Results
4.1.1. Causal Insights for Individual Dimensions: Analyzing Every Influence Path from Urban Environment to Green Travel Willingness
We identified four influencing factors and two mediating variables that affect the willingness to green travel of Shenyang residents. These factors can explain most of the variance in residents’ willingness to green travel and are consistent with the characteristics of the S-O-R theory [
47]. Based on the results of the structural equation model, the following nine paths that influence willingness to green travel have been sorted out, and the influential effects of these nine paths have been calculated by multiplying the local path loads (
Figure 6). The empirical research results show that the natural environment, social environment, built environment, and travel environment all positively influence the willingness to green travel. Among them, Path 5 and Path 7 have the strongest impact on the willingness to travel green, with effects of 0.24 and 0.26, respectively. This suggests that enhancing the built environment and the social environment has the most noticeable effect on residents’ willingness to travel green. The natural environment and travel environment do not directly impact willingness to green travel. However, they can indirectly influence willingness to green travel by affecting travel perception evaluation and attitude towards green travel, revealing the deep logic behind the phenomenon “the cold weather has people hibernating”. While the travel perception evaluation does not directly affect the willingness to green travel, it does have a positive effect on this intention through the attitude towards green travel, which is different from previous research results that emphasised that both travel perception and attitude have direct effects [
4]. This suggests that promoting green travel in cold regions requires more than just a satisfactory urban environment; it also necessitates a shift in residents’ attitudes towards embracing green travel as a preferred mode of transportation.
4.1.2. Aggregated Causality Assessment for Urban Environment Dimensions: Synthesizing Influence Paths on Attitudinal, Perceptual, and Behavioral Outcomes
Based on the paths described above, we integrated the paths of each of the four influencing factors to obtain the total effects of each dimension on the willingness to green travel and the two mediating variables (
Table 9). First, in terms of influencing travel willingness, the social environment factor has the highest impact on the willingness to green travel, with a total effect of 0.3326 over three distinct paths. The built environment factor, on the other hand, influences the willingness to green travel through two paths, with a total effect of 0.3180. In comparison, the natural environmental factor and the micro-travel environment factor have a total effect about one-sixth of the former, but it is still not negligible. Second, when analysing attitude towards green travel, the social environment factor has the most substantial impact, with a total effect of 0.3193 across two paths. The natural environmental factor, travel environment factor, and built environmental factor all have a total effect around 0.2, not much different from the former, showing their potential in shaping travel attitudes. Last, in terms of residents’ travel perception evaluation, there is a direct impact from the social environment, natural environment, and travel environment, with the social environmental factor’s effect being twice that of the others. A total effect of N means that if a one-unit change is made to a certain influencing factor, a change of N units in the dependent variable is expected. A larger total effect indicates that the output generated per unit input is higher. Therefore, under conditions of limited resources, we can prioritise optimising those environmental factors with the highest total effects. Alternatively, over the long term, we can systematically enhance the urban environment in a sequence based on the ranking of total effects. This will help change residents’ attitudes towards travelling, enhance their perception of travelling, and strengthen their willingness to green travel.
4.1.3. Considering Factor Interactions Between Urban Environment Dimensions: Uncovering Optimal Combinations for Green Travel Willingness Enhancement
Based on the SEM model results, it is evident that there are different standardised correlation coefficients among the four environmental factors, as depicted in
Table 10. This implies that a unit change in one environmental factor will similarly result in corresponding changes in the correlation strengths of related environmental factors. Therefore, a greater correlation strength indicates stronger synergistic effects among the environmental factors. Therefore, if sufficient resources are available, we can incorporate the correlation strength of the four external environmental factors and attempt to optimise the combination of these factors in a more comprehensive manner. This will enable us to achieve the efficient allocation of resources in prompting green travel. Taking the combination of the social environment with other factors to strengthen willingness to green travel as an example, the strongest correlation is found between the built environment and the social environment. This suggests that the combined effect of these two factors is more likely to be greater than the sum of their individual effects. By examining the correlation between these factors and their respective effects, we can conclude that the combination of the built environment and the social environment is the most effective. The combination of the social environment and the travel environment is the next most efficient, while the combination of the social environment and the natural environment is the least efficient.
4.1.4. Intra-Cluster Analysis: Prioritizing Tangible Elements Within Urban Environment Dimensions for Green Travel
Based on the CFA results, each category of environmental factors (latent variables) involves various specific environmental elements (manifest variables). In practical terms, adjusting these specific environmental elements is necessary to achieve corresponding changes in environmental factors, thereby promoting green travel. Factor loadings reflect the contribution of each manifest variable to the latent variable. Therefore, based on the factor loadings, we can propose environmental optimisation strategies suitable for winter cities. Among the factors related to the social environment, the social atmosphere has the highest factor loading, followed by social climate and policy encouragement, with factor loadings of 0.82, 0.76, and 0.74, respectively. This suggests that a green travel culture and implementing policies that incentivise green travel are the most effective ways to increase the willingness of residents in winter cities to travel in an environmentally friendly manner. These findings align with conclusions drawn by scholars such as A. Huang and D. Levinson regarding policy factors influencing travel modes [
59]. Within the built environment, the most influential factors are regional compatibility, recognition of urban construction, and green transportation infrastructure, all of which have loadings of 0.76. This aligns with the suggestion made by Schwanen T. and other scholars that the selection of travel modes is connected to the design of public transport stations and the level of completeness of other supporting facilities [
19]. In other words, well-designed public transport stations and comprehensive transport facilities make it easier for residents to choose public transportation. The air quality and weather conditions exhibit the highest factor loadings among the natural environmental elements, suggesting that a favourable air environment in a winter city encourages residents to opt for environmentally-friendly means of transportation. In the context of the travel environment, path guidance and the accessibility of starting and ending points both have the highest factor loading. To enhance residents’ willingness towards green travel, we can enhance the urban traffic’s signage system for guidance and augment accessibility by incorporating public transport stations. Operational efficiency represents another key factor. Enhancing the operational efficiency of public transportation, such as augmenting bus frequency and accelerating metro speed, positively influences citizens’ willingness to green travel.
4.1.5. Comprehensive Factor Evaluation: Manifesting the Influence of All Potential Influencing Factors on Green Travel Willingness
In this study, we identified 34 potential influencing factors on residents’ willingness to green travel in cold-region cities. To assess the strength of these associations, we calculated two correlation coefficients: the Pearson correlation coefficient, which measures direct linear relationships, and the structural correlation coefficient (SCC), a measure we propose that accounts for both direct and indirect effects within the SEM framework.
The SCC is calculated by multiplying the factor loadings of observed variables by the total path coefficients between latent variables and green travel willingness in the SEM. This approach captures the complex interplay of multiple factors, providing a more nuanced understanding of their contributions. As shown in
Table A8 in
Appendix D, the top 14 factors demonstrate significantly higher SCC values compared to the remaining 20, suggesting these are the most critical factors when considering the multifaceted impacts within urban environments on green travel.
Conversely, the Pearson correlation coefficients, listed in
Table A9 in
Appendix D, assess the bivariate relationships between each of the 34 potential influencing factors and green travel willingness. All factors are significant at the 0.05 level or above; their correlations are more uniformly distributed, making it harder to classify them as clearly as with the SCC.
However, by comparing the rankings from both coefficients, we identify nine factors—the convenience of site connection, overall satisfaction of travel, loyalty, perception of built environment, security, relevance of urban construction, road network density, policy encouragement, and general mood of society—where SCC rankings are noticeably higher. This implies that these nine factors, often underemphasised in traditional linear analyses, might play a substantial role through their interactions with other environmental factors in influencing green travel willingness. Given that complex interactions reflect real-life scenarios more accurately and align with the principles of complex adaptive systems theory, these nine factors, though individually less impactful, could collectively exert a significant influence on green travel. Future research and urban design should prioritise these factors to enhance green travel adoption effectively.
4.2. Implications of Findings
This study reaffirms the practicality of using the S-O-R theory in the context of decision-making in travel, particularly in winter cities like Shenyang. The findings provide evidence that the urban natural, social, built, and micro traveling environments have a significant influence on residents’ willingness to engage in green travel, consistent with the environmental influence theory [
9,
10]. Additionally, the study supports the attitude–behaviour congruence theory, indicating that changes in the urban environment can alter residents’ travel perceptions, evaluations, and attitudes, thereby influencing their green travel intentions.
In this research, certain concepts, such as the natural environment, social environment, built environment, and travel environment, may appear abstract. These categories serve as frameworks for analysing various factors influencing green travel willingness in cold regions. The natural environment, social environment, and built environment were derived from an exploratory factor analysis (EFA) of observed variables with high factor loadings, while the travel environment was identified by summarising prior studies and incorporating unique characteristics relevant to winter cities. The natural environment includes factors like weather conditions, air quality, topography, seasonal climate, and natural greening, which impact the comfort and feasibility of sustainable travel. Improvements here could involve developing weather-resilient pathways, enhancing greenery along routes, and adapting infrastructure for seasonal changes, such as snow removal in winter. The social environment encompasses policy encouragement, social atmosphere, and societal mood, which reflect cultural and regulatory influences on travel behaviors. Supporting green travel within this environment may involve implementing policy incentives, promoting environmental awareness, and fostering a pro-sustainability culture. The built environment refers to the physical infrastructure, including green traffic construction, urban construction identification, infrastructure relevance, supporting facilities, and road network density. Enhancements could include expanding public transportation options, designing pedestrian-friendly streets, and increasing connectivity between key urban areas to reduce car dependency. Last, the travel environment covers factors such as path support, route guidance, accessibility of starting and ending points, site connection convenience, operational efficiency, and technical support. Improving this environment involves maintaining clear and safe sidewalks, optimizing transit stop accessibility, managing road congestion effectively, and integrating smart travel information systems that guide users toward eco-friendly travel choices. By clarifying these concepts and providing actionable improvement strategies, this study contributes a more holistic understanding of how the urban environment can be optimised to encourage sustainable travel behaviours, particularly in winter cities.
The path analysis conducted in the study reveals that the social environment is the most influential factor in changing residents’ attitudes towards green travel, enhancing their perception of travel, and strengthening their willingness to green travel [
5]. This suggests that promoting a culture of green travel and implementing supportive policies can be effective strategies for improving green travel behaviours, particularly in winter cities.
While the built environment and travel environment are not the most dominant factors, they still play a crucial role. These factors, which are closely linked to urban design, can enhance the willingness to engage in green travel through both direct and indirect means. The combined effect of these two factors is particularly noteworthy, suggesting that urban planners should prioritise the design and advancement of the built environment and transportation infrastructure to foster green travel practices.
Given the high costs and long durations associated with constructing infrastructure in winter cities, it is important to strategically optimise urban spaces, increase public recognition of urban construction efforts, and develop green transportation infrastructure. By doing so, cities can encourage more residents to adopt green travel practices during the challenging winter months.
These findings offer valuable insights for urban planners and policymakers, providing a foundation for developing targeted strategies that enhance green travel behaviours in cold climates. However, it is important to note that while these recommendations are grounded in the study’s findings, further research with more representative data would be necessary to validate and refine these strategies.
4.3. Limitation of Research
The focus of this study is on the central city of Shenyang. However, to develop a comprehensive theoretical framework for understanding the factors influencing green travel behaviour in winter cities, it is essential to also examine the travel behaviours of individuals in counties and suburban areas where urban development is less advanced. The attitudes and behaviours of urban residents may vary significantly across different locations and cultural contexts, which suggests that our findings might not be universally applicable to all cold-climate cities.
Moreover, this study specifically examines the city’s external environment and residents’ attitudes as a collective entity, placing less emphasis on individual residents’ personal characteristics. Future research could incorporate additional variables to enhance the comprehensiveness of the theoretical framework.
Although the statistical analysis conducted in this study is methodologically rigorous, the non-random nature of the data collection limits the generalisability of the results. Therefore, the analysis should be viewed as illustrative of potential trends within the sampled population rather than as conclusive evidence applicable to the entire population of Shenyang. Future research with a more representative sample would be necessary to validate these findings.
5. Conclusions
This study employs the stimulus–organism–response (S-O-R) theory to explore how urban environments influence residents’ willingness to engage in green travel during winter in cold-region cities, using data from Shenyang, China. Through structural equation modelling (SEM), we identified four key environmental factors—social environment, built environment, natural environment, and travel environment—and two mediating variables, travel perception evaluation and attitude towards green travel, that collectively shape residents’ willingness to engage in green travel.
The analysis reveals nine distinct paths through which these factors influence green travel willingness, with the social and built environments having the most significant direct impacts. The natural and travel environments, while not directly affecting green travel willingness, exert crucial indirect effects by shaping travel perceptions and attitudes, illustrating the deep-seated interplay between these environmental factors. These findings highlight that promoting green travel in cold regions requires not only improvements to the urban environment but also a shift in residents’ attitudes towards embracing green travel as a preferred mode of transportation.
Further analysis of the total effects of each environmental factor shows that the social environment has the strongest overall impact on green travel willingness, followed closely by the built environment. The natural and travel environments, though less impactful, still contribute meaningfully, particularly through their influence on attitudes and perceptions. Additionally, the interaction between these factors indicates that combining enhancements in the social and built environments can produce synergistic effects, making this combination particularly effective for encouraging green travel.
To provide a more nuanced understanding of these influences, we introduced the structural correlation coefficient (SCC), which captures both direct and indirect effects. This analysis identified nine critical factors—such as site connection convenience, overall satisfaction with travel, and policy encouragement—that should be prioritised in urban planning. These factors, often underappreciated in traditional linear analyses, are shown to have a stronger influence on green travel willingness when considered within the broader context of interacting environmental influences.
The findings of this study advance the understanding of green travel behaviour in winter cities by illustrating the complex interplay between environmental factors, mediating variables, and individual attitudes. They offer actionable insights for policymakers and urban planners, suggesting that fostering supportive social environments and strategically enhancing the built and travel environments can effectively promote green travel practices in cold climates. Moreover, this research lays a foundation for future studies on sustainable urban development in winter cities, encouraging further exploration of the factors that influence environmentally friendly travel behaviours and contributing to the creation of livable, sustainable urban environments even in the harshest winter conditions.