1. Introduction
Earthquakes are among the deadliest natural disasters, often causing devastating damage and loss of life. According to EM-DAT statistics, earthquake disasters killed 752,498 people and injured around 1,574,000 between 1998 and 2018 [
1]. In China, the 2008 Wenchuan Earthquake triggered more than 200,000 landslides, resulting in more than 20,000 deaths [
2]. Nighttime earthquakes represent a long-term problem around the world. According to statistics, most earthquakes occur between 19:00 p.m. and 6:00 a.m. [
3]. The sudden and imperceptible characteristics of nighttime disasters pose great challenges for disaster relief. At nighttime, evacuations may be more inconvenient and perhaps more dangerous [
4,
5], often leading to more serious consequences. However, the majority of studies that investigate the factors that determine evacuation decisions and behaviors have been limited to daytime evacuations [
6,
7]. Therefore, the further investigation of nighttime evacuations is of vital importance.
Studies on people’s evacuation behaviors and relevant influencing factors during nighttime earthquakes are quite rare. The few studies on this issue have mainly focused on the built environment [
8,
9,
10,
11,
12], mental factors [
13], and social networks [
14]. Yu conducted an exploratory investigation into the mental and behavioral features of nighttime resident evacuations in Tianjin and found that the emergency lighting system was the most important environmental factor [
11]. Sun proved that the functions of social networks (i.e., neighborhood assistance, ridesharing, etc.) can become problematic during nighttime evacuations [
14]. However, comparably, there are many studies focused on evacuation behavior and its influencing factors. Lyu evaluated the risk of geohazards around Lanzhou in terms of both hazards and exposure [
14,
15]. Song studied the evacuation behavior of subway station passengers and their influencing factors and categorized this behavior into four types. He also pointed out personal factors, the built environment, and emergency regulations as the main influencing factors [
16]. Previous studies have also suggested that individual factors [
17,
18,
19], risk awareness and preparedness [
20,
21,
22], evacuation warnings and evacuation orders [
23], route choice [
24,
25], and social networks [
26,
27] all affect evacuation behavior. Despite the fact that abundant factors have been considered in studies focusing on evacuation behavior, few have assessed evacuation behavior at nighttime against the backdrop of residential areas. Among the studies that considered nighttime factors, they are limited to investigating the dynamics and mechanisms of evacuations in networks, and the connection between social networks and nighttime evacuation behavior has not been quantified. As such, this study attempts to explore this connection.
The objective of this study is to assess the characteristics of residents’ nighttime evacuation behaviors and to construct a theoretical hypothesis model of the influencing factors of residents’ nighttime emergency evacuation behavior. The study also aims to test how the influencing factors affect one another. The results of this study will help us to better understand residents’ perceptions and how they affect their behavioral intentions. The results also provide useful suggestions for guiding risk communication activities and disaster preparation.
This study was approached as follows: First, we conducted a literature review on built environment perception at night, night evacuation risk perception, social networks, and evacuation behavior at night. Then, we proposed our theoretical hypotheses and constructed a conceptual model. Second, the data sources, sample collection, and research instruments for this study were collected. A questionnaire on residents’ emergency evacuation behaviors and their influencing factors was devised and distributed to 285 residents of Shanghai. We validated the model using SPSS and Amos 24.0 software from IBM (Armonk, NY, USA), assessed the results, and considered the theoretical and practical contributions of this study. Finally, we examined the shortcomings and contemplated the directions for future in-depth research.
5. Discussion
On the basis of theoretical research on emergency evacuation behavior and its influencing factors and empirical research through questionnaire surveys, this study constructs a theoretical hypothesis model of residents’ nighttime emergency evacuation behavior.
First, four dimensions of evacuation behavior were identified: herd behavior, pro-social behavior, exclusive behavior, and autonomous evacuation behavior. Moreover, three dimensions of influencing factors were identified: spatial perception factors, risk perception factors, and social network factors. Through the reliability and validity analysis and confirmatory factor analysis of the data, it is proven that the four-factor model of evacuation behavior and the three-factor model of behavioral influencing factors can be identified. The results of the four behaviors are partly consistent with Helbing, D. [
60] and Lu, W.L. [
61], who found that the evacuation behavior of subway station passengers includes self-help behavior, herd behavior, exclusion behavior, and self-evacuation behavior, among others.
Second, the surveyed residents had the highest preference for voluntary evacuation behavior, a higher preference for pro-social behavior, and a lower preference for herd and exclusion behavior. These attitudes appear to conflict with the results of Song, C. [
17], who found that during the evacuation of a subway station, passengers will be most likely to exhibit self-help behavior but least likely to exhibit self-evacuation behavior. The reasons for this inconsistency may be that residential areas are where people are more familiar with and where they have solid social networks.
Third, the correlation between the latent variables was discussed, and the spatial perception factor was significantly positively correlated with exclusive behavior. Disaster prevention facilities at night and shelters in the community were two significant spatial influencing factors. The importance of disaster prevention facilities at night and shelters in the community has been proven in previous studies [
29,
30]. The former study also put forward more important factors such as the lighting facilities and quality of roads [
13,
29,
31,
32], etc. However, our study found the most crucial factors that lead to exclusive behaviors, which may help to guide community construction more directly.
Fourth, the results indicate that social network factors and herd behavior, as well as pro-social behavior and voluntary evacuation behavior, were significantly positively correlated, and the frequency of neighbor communication and number of neighbors were two significant social network influencing factors. In the social organization network, the frequency of participating in evacuation drills is a more important influencing factor; in the personal kinship network, it has less influence on the three types of behaviors. This is consistent with former studies, which found that risk-mitigation behavior may be more relevant to shared social norms and rules than individual perceptions in a culture in which one is considered interlinked with others rather than a distinct, independent, and distinguishable being [
62,
63]. Furthermore, our findings indicate that providing education programs to households may increase pro-social and preparedness behaviors.
6. Conclusions
Our study of the relationship between built environment perception at night, night evacuation risk perception, social networks, and evacuation behavior at night is of theoretical and practical importance. It may help us to understand whether and how these spatial, mental, and social factors influence different types of evacuation behaviors.
6.1. Theoretical Contributions
Our research makes two main theoretical contributions to the literature on evacuation behavior. First, the study extends the traditional Behavior-Based Safety (BBS) theory from industrial applications to disaster relief scenarios. Based on the BBS theory, a series of scales are used to measure residents’ behavior and a conceptual model of the impact of risk perception, built environment perception, and social networks on evacuation behaviors is constructed. This will help us to understand whether and how these three factors influence each type of resident evacuation behavior.
Second, previous studies on evacuation behavior have focused on the general situation, such as daytime shelters, daytime evacuation paths, and daytime risk perception, with less attention being paid to nighttime elements [
64,
65]. In this study, nighttime factors such as rescue facilities at night and darkness were added to the model, and such factors were empirically verified to assess their significant positive effect on behaviors, which may further affect the efficiency of earthquake evacuations. Our study also suggests that networks within communities, especially during evacuation drills, may have an important influence on resident behavior.
Third, the characteristics of the resident evacuation behaviors summarized in this study provide a theoretical reference for the formulation of community emergency plans. The behavioral influencing factors found in this study can also guide the preparation of comprehensive disaster prevention planning and departmental special planning.
6.2. Practical Contributions
Based on the analysis of the existing evacuation behavior characteristics and influencing factors, researchers can intervene with behaviors by changing the influencing factors. The favorable behaviors of residents during the night evacuation process are strengthened, and the unfavorable behaviors during the evacuation process are weakened so as to achieve a safe evacuation.
6.2.1. Measures for Exclusive Action
Exclusive behavior is an unfavorable behavior for night evacuations, interfering with normal evacuations, so it is necessary to weaken this behavior. The results of this study show that environmental perception factors have a certain influence on the generation of exclusive behavior. If there are good medical and other supporting facilities around the residential area, or if there are reasonable shelters in and around the community, the occurrence of exclusionary behaviors will be effectively alleviated.
In addition, in the nighttime environment, a good emergency lighting and indicator system can reduce the panic of residents and reduce the occurrence of secondary disasters caused by exclusive behavior. The night lighting in the residential area should follow the layout principle of “highlighting the key points and orderly linking” to form a “point-line-surface” emergency lighting evacuation system [
18]. In some existing residential areas in Shanghai, the lighting facilities at the entrance to each housing unit are outdated, emergency lighting does not cover every road intersection, and some important intersections and emergency shelter spaces lack emergency lighting reserves, which creates a significant safety hazard. The nighttime emergency indication system includes light signs, sound signs, and tactile signs. Most communities lack systematic, well-lit signs, and signs with sound and sensors are used less frequently, which fails to fully consider the needs of vulnerable groups.
6.2.2. Measures for Prosocial Behavior
The results show that social networks have a strong influence on herd behavior, prosocial behavior, and autonomous evacuation behavior, and a good social network is conducive to the occurrence of prosocial behavior. In a more mature social network, residents often help each other when disaster strikes because of mutual familiarity and trust. The analysis results show that a neighborhood communication network is the main influencing factor. This community can promote neighborhood communication by strengthening the construction of a humanistic environment. It can also promote the formation of the community and help carry out orderly disaster relief and recovery activities.
6.2.3. Measures for Autonomous Evacuation Behavior
A good social network will deepen residents’ familiarity with their surrounding environment, and people are more likely to engage in self-evacuation behaviors in a more familiar living environment. There are various forms of autonomous evacuation behavior. This study focuses on two behaviors: the tendency for familiarization and simplicity, and light tendency and risk avoidance. Autonomous evacuation is not necessarily detrimental to evacuation, and the community needs to guide autonomous evacuation through benign measures. On the one hand, it is necessary to strengthen residents’ knowledge of nighttime emergency evacuation. The community should regularly organize emergency evacuation drills, popularize prevention instructions for community disasters, and guide residents to participate in community disaster prevention practices. Disaster prevention knowledge is popularized in the form of lectures, training courses, broadcasts, etc. In the guidance for disaster prevention, the daily evacuation habits of residents should also be followed. For example, if residents have a tendency to move toward light at night, good emergency lighting should be set up at important intersections and safe entrances and exits. Additionally, the community can disperse the evacuation crowd through lighting to prevent the gathering of crowds.
6.2.4. Measures for Herd Behavior
Social networks play a positive role in promoting herd behavior. Just as in autonomous evacuation behavior, herd behavior may not only lead to congestion at evacuation exits and interfere with evacuation, but may also help guide crowds and speed up evacuation. On the one hand, the effect of herd behavior depends on the relationship between neighbors. A good neighbor relationship makes the small evacuation groups cooperate rather than compete, and the mutual following between acquaintances is conducive to the transmission of refuge information and the care of special groups. On the other hand, it depends on whether the community can carry out timely and effective guidance. For the community, it is necessary to improve the community disaster early warning system and safety management team system, and make the system connected with the city’s early warning platform. At the same time, the community should also establish a nighttime emergency plan to ensure the normal operation of the communication command system during nighttime disasters.
6.3. Shortcomings and Future Directions
Despite the contributions of this study, there are certain shortcomings. First, the quantitative nature of the study only explains the causal relationship between the studied variables. Thus, a qualitative study is encouraged to provide further information on the characteristics of the built environment, networks of community members, and their risk perception of the earthquake. Moreover, future research may pay more attention to social networks outside of the community and describe their mechanisms of action on residents’ evacuation behavior. Secondly, the conceptual model we built only explains a small amount of the variance of the influencing factors and actual behaviors, while some previous studies claimed that it was possible to explain a large proportion of the variance in predicting different behaviors in various situations using the integrated Behavior Model (IBM). Compared with that model, this study set a few scales regarding behavioral intentions, including attitudes toward the four behaviors, the perceived norms, and personal agency [
66,
67]. Therefore, future studies may use IBM to predict evacuation behavior more precisely. Third, there are limitations regarding the selection of questionnaire samples. The sample is limited to specific regions in Shanghai, and there is no confirmation with regard to the degree of compatibility with other cities. Furthermore, there are limitations in the selection of methods. The method used in this study is a questionnaire survey (
Appendix A), and the survey objects include residents who have not experienced disasters. Therefore, the evacuation behavior selected by the questionnaire may be different from the actual behavior after the disaster occurs. Thus, it is essential to analyze the behavior of residents in other cities besides Shanghai, and these analyses can be combined with the interviews of accident witnesses.