Social Factors: Human crowd in evacuation



In most of the cases, evacuation process has a social aspect too. Indeed, emergency situations usually involve more than one person: people working in the same office, a family living in its house, a city or even a whole region facing a flood or an earthquake. “Evacuation is rarely an individual process. Even in single-person households, the first response to the initial evacuation warning is to seek further information on the validity of the threat or to consult with a friend, co-worker, neighbor, family member, or relative. Evacuations usually take place in a group context (Drabek & Stephenson, 1971)” (Sorensen & Sorensen, 2006, p. 185).

This chapter will offer a literature review about social factors in evacuation, focusing on human crowd in evacuation and the “mass panic” approach, then talking about the relevance of leadership in this kind of situation and concluding with some information regarding communication in evacuation.

Human crowd in evacuation

In its first decades, psychological research about crowd movements in emergencies has focused on the “mass panic” approach (Le Bon, 1895). From this point of view, crowd is seen as an irrational group of individuals driven by instinct of personal survival. Social bounds dissolve and panic and confusion arise (Strauss, 1944) resulting in competitive behavior with people attending to their own needs. Fear cancels social and cultural constrains in favor of the short-term personal interest, which is evacuate as quicker as possible. Quarantelli (1954) have pointed out some conditions that would lead to mass panic: the perception of an immediate major physical danger, the feeling of possible entrapment and the perception collective powerlessness, and a feeling of individual isolation in a crisis situation. In this condition, moreover, the level of attention is reduced and people start to conform to other individuals because of social contagion (Helbing & Johansson, 2010). “This herding behavior is in some sense irrational, as it often leads to bad overall results like dangerous overcrowding and slower escape. In this way, herding behavior can increase the fatalities or, more generally, the damage in the crisis faced” (Helbing & Johansson, 2010, p. 14). Nevertheless, in some conditions this herding behavior, which can be explained as a stronger tendency of follow other people under stress, can be useful, for example in unfamiliar environments or in case of smoke caused by a fire. In such scenarios evacuees may be more likely to obtain information on exit routes by watching or following others (Bode & Codling, 2013). According to Helbing and Johansson (2010), “optimal chances of survival are expected for a certain mixture of individualistic and herding behavior, were individualism allow some people to detect the exit and the herding guarantees that successful solutions are imitated by small group of others” (p. 17).

Laboratory experiments and real past emergency situations have shown that “mass panic” approach doesn’t really explain people’s behaviors in emergencies, because antisocial and selfish behaviors are rare and people continue to be social actors embedded in social organizations (Drury, Cocking & Reicher, 2008). For example in an analysis conducted by Gershon and colleagues (2007) on the WTC 9/11 evacuation participants described a sense of social cohesion creating a protective atmosphere in the groups that were leaving the towers.

So, other approaches have been developed in the last decades and nowadays coexist in explaining crowd behaviors. Some of them are:

    • the normative approach, which postulates that social roles, norms and rules of conducts that people use in everyday life remain the same even in emergency situations (Johnson, 1987);
    • the affiliation model, which affirms that people are more motivated in seeking for their familiars and even to stay with them more than simply exit (Mawson, 2005). In particular, “the typical response of threat and disasters is not to flee but to seek the proximity of familiar persons and places; moreover separation from attachment figures is a greater stress factor than physical danger” (Mawson, 2005, p.101);
    • the self-categorization theory (Turner, 1982) that explains also the mutual aid amongst strangers and the solidarity thanks to the identification of some aspects of oneself with the other (Drury, Cocking & Reicher, 2008). “The shared fate could create a sense of ‘we-ness’ among those who are similarly threatened according to which social bonds are created and strengthened” (Girod, 2012, p. 6). It is interesting to underline that this social bond is so hard to resist also after that the threat has gone.

The assumption of evacuee as actors acting rationally and normatively has important implications and some of the aspects of human behavior in evacuation that we mentioned above have repercussion if it is a crowd who has to evacuate. One of this is the decision about the exit to use. Lots of studies have pointed out that people in evacuation use the exit they usually came in because it is the most familiar (Benthorn & Frantzich, 1996; Johnson 2005; Proulx 2001). In case of huge groups of people this can lead to potentially dangerous collective phenomena at high pedestrian densities. Indeed, the sheer press of people eliminates the possibility to change route or to determine individual’s movements in the space (Aguirre, 2005). Overcrowding in preferred routes may result in injuries or fatalities among the evacuees. Recently, Bode and Codling (2013) have found an opposite result regarding exit choice in evacuation. Indeed, their study, based on a simulated evacuation in a virtual environment, shows that people normally don’t have a preference on the familiar route, but look for the emergency exit. The only experimental condition in which the preference for the familiar route is confirmed is the “motivational” one. In this case time pressure was put the to participants by a motivational message inviting them to beat the current fastest time to reach the new target during the countdown. Only in this condition of stress and time pressure they were more likely to choose the more familiar route, even if it was the most crowded one.

Analyzing crowd behavior in evacuation, Aguirre (2005) have highlighted some interesting group characteristics that play a relevant role. First of all the size: the bigger the group, the more difficult and longer it will be for the group todecide how to response to the danger. Group composition and heterogeneity is connected to size. The bigger the group, the more heterogeneous it could be. Variation, differences of opinions and relevant experience about what to do will result in longer time to decide what to do (Aguirre, 2005). This result is in contrast with the critical mass theory (Marwell & Oliber, 1993), which states that bigger groups have a higher probability of having a critical mass of members able to solve the situation. For this reason research is needed to understand how group heterogeneity impacts the decision to evacuate and evacuation behavior. Groups vary not only in terms of size and heterogeneity, but also in terms on amount of resources available. Aguirre (2005) states that: the greater the amount of resources available to the groups, the slower will be their adoption of evacuation behavior, for it will take more time for the groups to agree on how to use these resources and integrate them into their new division of labor.


Emergency measures’perceptions and attitudes

Emergency measures’perceptions and attitudes      

An interesting survey commissioned by the National Fire Protection Association has focused on some individual cognitive aspects that play an important role in the effectiveness of the evacuation process (Zmud, 2007). It explored the general knowledge, attitudes and perceptions about high-rise building safety and emergency evacuation procedures in case of fires and factors that contribute to them, both in commercial and in residential buildings in the U.S. The idea was that attitudes and perceptions towards evacuation were change after the 9/11 terroristic attack to the World Trade Center and that a new overview of them was needed to “develop more appropriate occupant notification and communication strategies and to build evacuation and occupant relocation strategies, emergency responder strategies, and education programs and messages” (Zmud, 2007, p. 1). Actually, the 9/11 WTC terroristic attack heightened concerns about safety in high-rise buildings (more for commercial occupancies’ respondents than for residential occupancies’ respondents). Evacuation drills were seen as somewhat or very beneficial from the 89% of the survey’s participants, and the top suggestion was precisely to improve safety through increasing the number of drills. In general, occupants of commercial buildings feel they are prepared and trained to evacuate, e. g. “I am prepared to take necessary action in case of a fire in my building” 4.3 mean score (with 1 meaning I strongly disagree and 5 meaning I totally disagree), “I am well informed regarding safety procedures in my building in the event of a fire” 4 mean score. The 98% of the occupants of commercial buildings knew where the emergency exits were (against 95% of occupants of residential buildings). Understanding attitudes, beliefs and perceptions is of utmost importance because they affect the likelihood of a specific behavior, in this case of the evacuation process.

However, knowledge, perceptions and attitude about emergency measures vary within the population. They change between ages (e.g. teenagers versus elderly) because they are connected with previous experiences, between genders, but they vary even more between cultures. Carter-Pokras, Zambrana, Mora and Aaby (2007) have studied perceptions and knowledge about emergency preparedness between Latin American Immigrants (the largest minority group in the United States) using focus groups. The assumption on which CarterPokras and colleagues cased their survey is that “cultural groups respond to risk and crisis communication on the basis of their perceptions and ways of thinking, and these differ from group to group” (Carter-Pokras et al., 2007, p. 466). What emerged from the investigation is that few participants had received information about emergency measures because of the language barrier. Indeed, disaster warning in the U.S. are usually broadcasted only in English, and lot of Latin American Immigrants, even if they have moved since several years, are not able to perfectly manage English (especially elderly people). Moreover, focus group participants themselves admit they are not motivated to engage this topic: “Latinos are lazy to read informational bulletins and go to meetings…sometimes the school holds the meetings to talk about thingslike this, but very few of us show up…and they wait until it happens to react”. They also confess distrust of governmental authorities and so also to their indications and rules to follow in case of emergency. This mixture of factors lead to a higher vulnerability for minorities in case of emergency and this is a key factor to take into account in order to develop a real comprehensive emergency management.


Individual Factors in Evacuation: Risk perception

Individual Factors in Evacuation: Risk perception


During the 80’s, risk assessment emerged as a new field of study thanks to the development of chemical and nuclear technologies. Withrisk assessment Slovic (1987) refers to identifying, characterizing and quantifying risk. People assess risk in an intuitive and subjective way. Risk perception is based on the assumption that usually the objective assessment of a risk (made for example by an expert) differs from the subjective evaluation (Ho, Shaw, Lin, Chiu, 2008; Slovic, 1987).

In natural hazards, risk perception depends on the characteristics of the hazard itself and on the features of the victims and generally of the people leaving around. Of course environmental disasters vary according to different features (for example they can be predictable or unpredictable, more or less geographically located) and the human response to them change as well. Ho and colleagues’ research (2008) is interested to better understand this point. Taking into consideration floods and landslides in Taiwan, as they do, risk perception of the two hazards is very different depending on the differences between them. Floods are a natural phenomenon that occurs as a predictable annual event and usually it ends with lots of damage that cause high economical loss but relatively few human casualties. There are several preventative measures that people can adopt trying to reduce the financial loss, like position sand bags, move belongings to the upper floors, and so on. On the other hand, landslides are random events and their main concern is the human casualties. People main contrast this type of hazard with a unique measure: evacuation. These differences result in differences in risk perception. Ho and colleagues (2008) for example founded out that “a higher sense of controllability (know mitigation actions, able to control) can effectively reduce the perceived disaster impacts for the landslide victims, but not for the flood victims” (Ho, Shaw, Lin & Chiu, 2008, p. 640).

Victims’ characteristics that affect risk perception are: previous experience with disasters, gender and education (Gustafson, 1998; Sjöberg, 2000; Ho, Shaw, Lin & Chiu, 2008). People that have experienced the hazard before reports higher level of fear, consider the hazard to be more life threatening and perceives a higher occurrence rate of disasters. Females experience more fear associated to the hazard, think that it is more life threatening and are more scared regarding financial loss than males. This is probably because women are more sensitive, more physically vulnerable and have lower socio-economic status than males. Higher level of education means that people are more able to understand instructions and information and have higher level of controllability. Others personal dimension that the research have been considered during the last 15 years are: age (Hermand et al., 1999), training in science (Karpowicz-Lazreg & Mullet, 1993), income (Flynn et al., 1994; Palmer, 2003), religious orientation (Sjöberg & af Wahlberg, 2002), political preferences (Sjöberg, 2000), culture (Mullet et al., 2005), risk attitude (Vollrath et al., 1999; Sjöberg, 2003), personal experience with the hazard (Barnett & Breakwell, 2001;Rogers, 1997), values (Sjöberg, 2000), social trust (Siegrist et al ., 2000; Vicklund, 2003), anxiety (Bouyer et al ., 2001; Källmèn, 2000), self-efficacy (e.g., Kouabenan, 1998; Källmèn, 2000), locus of control (e.g., Källmèn, 2000), worldviews (Bouyer et al., 2001; Brenot et al., 1998), new age beliefs (Sjöberg & af Wahlberg, 2002), environmental beliefs (Sjöberg, 2003), the viewpoint (risk for self or risk for others) taken by the person (Hermand et al., 2003; Sjöberg, 2000), and finally the classical personality factors (Sjöberg, 2003).



Individual Factors in Evacuation:Knowledge and training



As shown in the previous section, there are some factors related to the occupant that are relevant in the evacuation process. In this chapter some of them will be presented more in detail. Primarily, research findings about knowledge and training in evacuation will be provided. Then, there will be a focus on risk perception, taking into account all the factors that affect it. Finally, some information of the role of occupants’ perceptions and attitudes about emergency measures during an evacuation will be reported.

Knowledge and training

There is another crucial factor in evacuation that has to be taken into account: knowledge of the emergency procedures and training (Gershon et al., 2007; Kuligowski, 2008). “During the evacuation process, a high level of knowledge related to fire safety procedures, staircase location, and building layout, coupled with ongoing sensory cues that indicated that the situation is dangerous, supported the evacuation process” (Gershon et al., 2007, p. 171). Kuligowski (2008) has demonstrated that if an occupant has knowledge of fire training the likelihood of perceiving a cue and of defining the situation as a risk increases. Moreover, the time needed for the perception and interpretation of the cue phases is lower and all the evacuation process results to be quicker and more efficient. Another element that plays a key role is an informative evacuation alarm system that gives more detailed information about what is going on. Different from a normal alarm with a ringing bell, an informative evacuation alarm system also provides a human voice specifying the type of hazard, the affected areas, and other information that even trained people can’t know. The main advantage of this type of alarm is that it can reduce the time spent in the interpretation of the cue. The more occupants are well trained and informed about what is happening and what they are expected to do, the quicker and more efficient the evacuation will be (Benthron & Frantzich, 1996). Shields and Proulx (2000) have underlined the difference between trained and untrained occupants. Trained, prepared and experienced people are facilitated in recognition, rationalization and effective actions, while untrained or inexperienced people resort to unstructured information and acquiesce to authoritative instructions or other leadership when available.

A drill is a method of practicing an evacuation from a building in case of different hazards and so of training people to be prepared in case of an emergency. Drills are made to be as realistic as possible: usually the alarm sounds and the building is evacuated exactly like in a real emergency situation. Drills purposes are to measure the time needed to evacuate, to ensure that it is reasonable (in case it is too much the problem with the evacuation process is identified to be remedied) and to train occupants. Drills and other specific emergency trainings are the best way to make people aware of evacuation protocols and procedures, as well as possible means of egress from the building (Kuligowski, Gwynne, Butler, Hoskins & Sandler, 2012). Nevertheless, even though drills are scenarios that realistically recreate the emergency situation, some processes and behaviors differ in real evacuations and in drills. As Bode and Codling (2013) state: “Evacuation drills are perhaps the closest proxy for evacuations. However, if these drills are to be highly realistic, they are potentially dangerous to participants and therefore not ethical. When risks to participants are avoided, drills are unlikely to convey the real stress to which evacuees are exposed” (Bode & Codling ,2013 ,p. 348). Drills don’t have the stress components of the ambiguity of some emergency situation, not even the physiological or psychological exposure to some hazard’s effects like smoke, or falling objects (Bryan, 1999). Taking into account this weak point, drills are a good tool to build an efficient emergency management anyway and staff training is a worth making investment and has to be included in the emergency management (Shields & Proulx, 2000).

Previous experience also plays an important role in facilitating the evacuation (Gershon et al., 2007). Indeed it can be considered as a kind of previous training. Moreover, prior individual emergency experience could fill gaps in organizational preparedness, and, on the other hand, a high level of organizational preparedness could compensate for deficiencies at the individual’s preparedness level (Gershon et al., 2007).

According to Aubé and Shield (2004) not only the knowledge about the emergency procedures, but also the knowledge of the environment is important for an effective evacuation. Nevertheless, some type of buildings, such as hotels, commercial buildings, stadiums, etc. are only occasionally used by people that obviously can’t be familiar with the environment. In these cases “using security personnel or other key persons that can help the evacuation of the crowd is the most practical way to enhance the security of a crowd” (Aubé & Shield, 2004, p. 602).


Factors in evacuation response: an integrative model

Factors in evacuation response: an integrative model 


The hazard response performance depends not only on human actions. A recent review about human behavior in emergencies, in particular in fire situations, attests that it mainly derives from 3 factors: danger factor, human factor and environmental factor (Kobes et al., 2010).

The danger factor refers to the characteristics and type of the hazard. The hazard may be due to: nature (see Figure 3) or human being (see Figure 4). In particular, Kobes and colleagues (2010) have focused their attention on fire characteristics, dividing them in: perceptual feature (elements which can be seen, smelt or heard that influence the time it take to discover the fire), fire growth rate and heat, smoke yield and toxicity.  For other type of hazards characteristics will be different but always present. For example, earthquake could cause the falling of objects or part of the building that can obstruct the escape route and delay the evacuation. Other type of disasters like tornados could cause problems to the light system delaying the evacuation process due to the lack of light. Moreover, it has to be taken into account that different precautionary and protective actions can be performed to face these different types of hazards and people perceive them differently (Slovic, 1987).

Figure 3 – Natural hazards

Figure 4 – Human hazards

The human factor is composed by individual features, social features and situational features (see Figure 5).

Individual features include: personality (Kobes et al., 2010), knowledge and experience (Gershon et al., 2007; Kobes et al., 2010; Kuligowski, 2008), powers of observation (Kobes et al., 2010), powers of judgment (Kobes et al., 2010), mobility (Kobes, et al., 2010; Shields & Proulx, 2000), disability (Boyce, Shields & Silcock,1999a, 1999b, 1999c; Proulx, 2002), gender (Boyce, Purser & Shields, 2011), age (Spearpoint & MacLennan, 2012), body mass index (Spearpoint & MacLennan, 2012), race and ethnicity (Fothergill, Maestas, & DeRouen Darlington, 1999).

With personality, Kobes and colleagues (2010) refer to the following dimensions: leader or follower, level of stress resistance and self-efficacy. They state that, in the event of fire, the majority of people adopt the role of a follower, waiting for others to act. Moreover, people differ in terms of level of stress resistance and this can affect the evacuation process because too much psychic stress can impair cognitive processes and delay the response. Finally, “selfefficacy influences the choices that people make, the effort that they put in, how long an action is persisted with if obstacles are encountered (and people fail) and feeling. This is related to Bandura’s Social Cognitive Theory” (Kobes et al., 2010, p. 6).

Observation is crucial to estimate the threat of danger validating the cue. People who have a pronounced power of observation and judgment is faster in perceiving the cue by seeing, hearing, smelling or feeling it and this will result in a faster interpretation and validation of the cue before starting evacuating (Kobes et al., 2010).

Age has a direct effect on the evacuation speed (Spearpoint & MacLennan, 2012). Indeed there are multiple functional limitations associated with ageing that affect walking capacity (Ayis, Ebrahim, Williams, Juni & Dieppe, 2007). A slower walking pace will result in a slower and less efficient evacuation. With a global population facing an increasing ageing problem, age is getting more and more a crucial aspect that can have a weight in calculating and predicting evacuation times. Ageing has also a consequence that has an effect on the evacuation performance: the increase in the risk of falling and the development of the fear of falling (Stel, Pluijm, Deeg, Smit, Bouter & Lips, 2003). This is because “functional limitations can directly predict the risk of falling and hence the lack of confidence that would be associated with reaching safety in an evacuation” (Spearpoint & MacLennan, 2012, p. 1677). Fear of falling increase the possibility of plug flows that can be very dangerous in the evacuation process because will results in higher evacuation times.

Also obesity affects walking capacity and have an effect on the speed of the evacuation performance (Spearpoint & MacLennan, 2012). Medical studies have shown that the degree of fat mass is directly linked with increases in musculoskeletal pain and arthritic conditions. These elements lead to several functional limitations and also affect walking speed. “The increase in obesity and thus body size also relates to a marked increase in the potential for plug flow where there is no room on the landings for people to rest. Group altruism can be a further cause of plug flow where an obese person may need help” (Spearpoint & MacLennan, 2012, p. 1682).

Both age and obesity affect occupants’ mobility, which can be considered as the capacity to move out of the building. As it is easy to understand, reduced mobility causes delays in evacuation (Kobes et al., 2010).

Gender can also play an important role in evacuation performance, such as when males give priority to women and children or staff guiding other occupants (Boyce, Purser & Shields, 2011).

Other individual characteristics that are involved in the response are race and ethnicity. The interesting review by Fothergill and colleagues (1999) divided the response to a natural hazard into several categories in order to clarify the difference between several racial and ethnic groups in the US. The hazard response is divided into: risk perception, preparedness, warning communication and response, physical impacts, psychological impacts, emergency response, recovery, reconstruction. For example, the authors report that Afro-Americans are more fatalist then Anglos (white Americans) regarding earthquakes, and feel that there is little or nothing one could do to protect against them. Moreover, Hispanics are more likely than the others ethnic groups to use social networks for disaster information and they find mass media to be reliable more than Anglos and Afro-Americans. These are only some example from the review by Fothergill and colleagues (1999) that indicate how also aspects like race and ethnicity are relevant occupants’ characteristics that affect the hazard response.

Some studies have addressed the problem of elderly occupants or people with disabilities (Boyce, Shields & Silcock, 1999a, 1999b, 1999c; Proulx, 2002). Clearly these categories of occupants present specific characteristics that affect their mobility. The ideas that have been developed to solve this problem include the use of particular elevators or the creation of rooms in which they can shelter waiting for people to rescue them (Proulx, 2002).

Knowledge and experience are also important individual factors. Their contribution to the evacuation process will be explained in detailed in the next chapter of this literature review.

Social features incorporate: affiliation (Kobes et al., 2010), task fixation (Graham & Roberts, 2000) and role/responsibility (Boyce, Purser & Shields, 2011; Kobes et al., 2010).

Talking about affiliation, there are empirical evidences from studies investigating evacuation from residential buildings that family members respond as a group, often delaying the evacuation time (Kobes et al., 2010).

Other studies have pointed out that people engaged in tasks are inclined to first finish the job before performing other type of actions such as evacuating (Graham & Roberts, 2000).

Finally, what Kobes and colleagues (2010) report in their literature review is that “in the first instance people adhere to the role expectations appropriate to the function of the building where they are located […] Moreover, those who have organizational responsibilities for a building, by virtue of their roles or positions, such as waitresses and deportment managers, are also inclined to assume these duties during an emergency situation.

Situational features comprise: alertness (Kobes et al., 2010; Shields & Proulx, 2000), familiarity with the layout (Benthorn & Frantzich, 1996; Kobes, et al., 2010; Shields & Proulx, 2000), stress, perceived threat, fatigue (Averill et al., 2007; Galea et al., 2008; Spearpoint & MacLennan, 2012).

Evacuation can be a really demanding task from the physical point of view in case of high buildings with lot of floors and stairs. People sometimes would need to take a rest because of fatigue, and this problem will increase in the future due to the growing of a sedentary lifestyle with people not used to physical efforts (Spearpoint & MacLennan, 2012). Breaks caused by fatigue will have a delay effect on the evacuation process that has to be taken into account.

Occupants that are familiar with a building know how to move within it because they use it daily. Usually they are also aware of the safety procedures and emergency plan. However, familiarity with the building doesn’t lead automatically to the knowledge about emergency plan. So familiarity can be considered as a facilitating factor for the likelihood of an efficient evacuation. Nevertheless it is not a sufficient indicator. It is well known that the preference of most occupants is to evacuate through the way they came in (Benthorn & Frantzich, 1996).

Alertness is described as “the involvement of people with the activities being carried out within the building, or their interaction with the other occupants of the building which can affect their awareness of other circumstances. For instance, if people are in bed and asleep, their response to a fire alarm is likely to be considerably delayed” (Shields & Proulx, 2000, p.99). Kobes and colleagues (2010) also underline that alertness could be reduced by the consumption of alcohol, drugs and narcotics.

Figure 5 – Human factors

The environmental factor is composed by situational features and engineered features (see Figure 6). It provides the primary conditions for the possibility of surviving a hazard.

Situational features comprise: occupant density of the space (Aguirre, 2005; Kobes et al., 2010), wayfinding/route choice (Kobes et al., 2010) and maintenance of escape routes (Kobes et al., 2010).

Occupation density refers to the number of people in a building. Previous researches have defined that there is a direct correlation between high occupation density and a high probability of fatalities in case of disasters (Aguirre, 2005; Kobes et al., 2010).

Way-finding has already been debated in the previous chapters of this paper. Here we will only add some environmental factors that can help the way-finding process: visual access, level of architectural differentiation, layout, familiarity, presence of signage and location marking (Kobes et al., 2010).

The last point is composed by the maintenance of the escape routes. As it easy to understand, keeping the escape routes free and practicable is a basic and necessary factor to obtain a successful evacuation (Kobes et al., 2010).

Engineered features include: building lay out (e. g. number of floors), its installations (e. g. stairs, evacuation lifts, sky bridges, refugee floors, emergency exit that automatically open), emergency materials, but also its size (e. g. high rise buildings) and the type of building (residential or commercial).

In case of evacuation from buildings, an important aspect is the high of the building. Buildings greater than 23 meters are considered as high-rise buildings. The research considers this type of building as a separate category and deals with them independently. Evacuating from them, indeed, is more complex and need more time, and new variables have to be analyzed (like the choice of stairs or elevators) so that strategies, procedures and egress models for simulating high-rise buildings evacuation scenario are usually different from the others (Gershon et al., 2007; Hassanain, 2009; Zmud, 2007). Scholars studying high-rise building evacuation focalize on elements like stairs (stairs design in general, number of stairs, stairs width and length, merging streams of occupants in the floor-stair interface), special evacuation lifts, sky bridges that can be used to evacuate people at a level different from the ground floor to reduce the vertical evacuation travel distance (only in case of fires) and refuge floors (only in case of fires) (Ronchi & Nilsson, 2013).

Design features change depending on the type of building: office occupancies are different from health care facilities and different from hotels or residential apartments. For example, “from a design perspective, office buildings have generally open concept floor plans, which cause a reduction of the possibility to contain the fire within a compartment […] Fire systems are generally well-maintained, and may include recorded voice messages and fire alarms” (Ronchi & Nilsson, 2013). In residential buildings people are familiar with the environment, while in hotels not.

Some facilitating characteristics in buildings are the presence of focal points or emergency exits that automatically open in case of emergency (Benthorn & Frantzich, 1996; Shileds & Proulx, 2000).

Figure 6 – Environmental factors




Human behavior in evacuation : Decision making

Human behavior in evacuation : Decision making


During the decision making phase (Kuligowski, 2008) or the cognition stage (Galea et al., 2010) occupants can decide between different options. One of these is to evacuate the building.

According to Gershon and colleagues (2007), who have conducted an analysis on the World Trade Center 9/11 evacuation, the evacuation decision-making is composed by the decision to initiate the evacuation and to go on with the evacuation until reaching the area outside the building.

The decision to initiate the evacuation depends on several factors that can be grouped in three levels of analysis: individual, organizational and environmental. At the individual level there are some conditions that will facilitate the decision to leave and other that will impede this kind of action.

In the specific case of the WTC 9/11 evacuation the first were: emergent perception of risk formed by sensory cues, intuition, prior experience in WTC in 1993 (a previous terroristic attack), thought of a terrorist event, knowledge about how to exit and the communication with significant to leave the building.

On the other hand, the barriers were: a low knowledge level about the building layout or the emergency procedures, delaying behaviors (such as calling others or gathering personal belongings), fear of physical capabilities and the fact of being new to the job with a subsequent hesitation for fear of consequence of leaving. Similarly, at an organizational level the authors founded that an occupant instructed by a person in authority or by a colleague to leave were more likely to decide to evacuate.

Also a person with an authoritative voice shouting the directions to egress the building was a facilitator.

On the contrary, no guidance or ambivalent or contradictory messages played an important role on the occupants’ decision to not evacuate.

Taking into account the environmental level, important factors were: hearing, seeing or feeling the explosion or a flash of light or the plane hitting the first building or smelling smoke; while factors that have prevent the decision were communication failures and the fact of no receiving environmental cues.

Also the decision to progress with the egress can be analyzed using the 3 different levels.

Considering the individual, the decision to keep on leaving was more likely in case of: high degree of fire safety knowledge, prior experience, building knowledge, good footwear, the presence of a leader or a crowd to follow and the heeded encouragement by others to keep moving.

At the organizational level of analysis, it was found that management behaviors (executive used bullhorn to order evacuation, people left and kept going) but also first responders in the lobby assisting with directions out of the building and encouraging evacuees to keep going were facilitator to the decision of proceeding with the evacuation.

Regarding the environment, clearly, strong environmental cues, supportive social milieu on staircase and good condition of the stairwell were crucial factors in the progress of the evacuation process




Human behavior in evacuation

Human behavior in evacuation  

How people behave during an escape is referred as evacuation behavior. Lots of scholars have tried to develop a comprehensive and integrative model of human behavior in evacuation from buildings (Gershon et al., 2007; Kobes et al., 2010; Kuligowski, 2008) and most of them have concentrated their attention on the individual actor, taking into account issues like individual threat perception, individual decision making in crisis (Aguirre, 2005).

Another characteristic of this type of studies is that they usually concern evacuation in case of fire (Aubé & Shield, 2004; Benthorn & Frantzich, 1996; Graham & Roberts, 2000). A possible explanation is that fires occur more often than other disasters like earthquakes or hurricanes and that they don’t depend on any geographical position. So they are more common. As will explained later on, the type of hazard can change the behavioral response, but lots of findings can be applied to different situations of evacuation. In this literature review we will present two recent different behavioral models for evacuation, one presented by Kuligowski (2008) and the other one developed by Galea, Dreere, Sharp, Filippidis and Hulse (2010). They are not in contrast with one another, but they only differ regarding the terms used and some details.  Kuligowski (2008) suggests an interesting conceptual model of the behavioral process for evacuation from building fires consisting of 4 phases:



Figure 1 – Kuligowski’s evacuation process


    1. perception of the cue/s – this phase involves occupants receiving cue/s (which can be physical or social) that makes them aware that something in their environment has changed. This step is usually characterized by uncertainty, misunderstanding and inefficiency. The degree of uncertainty regarding the danger of the situation delays the beginning of the evacuation (Kobes et al., 2010). At first occupants get information about the change in the situation. This can be done by direct observation, such as smelling smoke or perceiving the building’s shaking, or by indirect information, like a fire alarm (Benthorn & Frantzich, 1996).
    1. interpretation of the cue/s, situation and risk – occupants attempt to organize the perceived cue/s into a framework to construct a meaningful story based on it and to make sense of the situation by imagining what is happening. The interpretation of the cue is not always rational. Indeed, there is a persistent and strong normalcy bias that emerge in this stage, in which occupants misunderstand the cue and interpret it as a normal feature of daily routine (Aguirre, 2005). Is crucial to nullify this bias for occupants to start the evacuation. Moreover, it has to be taken into account that cues are interpreted differently in different buildings (Benthorn & Frantzich, 1996). For example, smoke in a restaurant kitchen is not interpreted as an evidence of fire but as a normal occurrence;
    1. decision making – at first, occupants look for options about what to do, by performing mental simulation, and then choose one of them. This phase is influenced by time pressure that stresses occupants and limits their mental resources in choosing the best option. Usually, when occupants become aware of the situation, the arousal level increase, but it shouldn’t be neither too high or too low. If it gets too high, the tendency of stop thinking and acting in panic rises. If it gets too high, occupants might ignore the danger (Benthron & Frantzich, 1996).
    1. action – occupants perform some types of physical act, which can be evacuating but also waiting, seeking information, alerting or assisting others or preparing for evacuation. One element of this phase is way-finding. “Way-finding, within the building evacuation context, describes the process by which an individual located within an unfamiliar and arbitrarily complex enclosure attempts to find a path which takes them to a place of relative safety or at an exit leading them to the exterior of the enclosure” (Xie, Filippidis, Galea, Blackshields & Lawrence, 2009, p. 289). According to Arthur and Passini (1992), way-finding is a cognitive process composed of the following abilities: a cognitive-mapping or information generating ability, a decision-making ability and a decision executing ability. The first is needed to understand the environment, the second to decide what to do and the third one to effectively perform the action choose. This formalization implies also the possibility to modify the plan while the process is going on, for example in case of unforeseen. Other authors have considered the way-finding as composed of different stages. Downs and Stea (1973), for example, propose to divide the way-finding process in: spatial orientation, the selection of the initial route from the starting point to the target (for example the exit door), continuous monitoring of the route taken and the ability to recognize when the target has actually been achieved. Research on way-finding has found out that people use specific criteria to choose the path to follow. Some of them are the same in all the different environments, others not. For example, shortest distance or fewest turns are important factors both in outside and in inside environment. On the other hand, most scenic/aesthetic route and first noticed route are criteria only used in case of urban based way-finding (Golledge, 1995). According to Kuligowski (2008) on 30 evacuation models reviewed, only 2 included some wayfinding features. This neglect results in less realism of the evacuation models, because they assume that all the individuals know exactly all the features of the environment in which they are. “The introduction of way-finding into evacuation simulation potentially overcomes the problem of unrealistic evacuation dynamics by generating more complex existing behaviors with resulting added complexity in occupant flow dynamics” (Veeraswamy, Lawrence & Galea, 2009, p. 511).

Galea, Dreere, Sharp, Filippidis and Hulse (2010) consider the first 3 elements presented by Kuligowski (2008) in the same phase, called response phase, separated from the evacuation movement phase (see Figure 2).

The response phase is comprised of 3 stages: notification, cognition and activity. The notification stage is similar to what Kuligowski (2008) calls the perception of the cue phase. Indeed, in this step, a cue conveys to the occupants that an unusual and potentially dangerous event is occurring and that they have to evacuate. The notification stage ends with the beginning of the cognition stage, which is analogous to the interpretation of the cue and decision making phases. Nevertheless, Galea and colleagues (2010) specify three different types of decisions about how to react:

    1. the cue is not enough strong or clear to convey to the occupants the immediate need to evacuate, so they come back doing what they were engaged to do. In this case, the cognition stage continues until one of the other two possible responses occur;
    1. the occupants understand the need to evacuate. They stop with other tasks and start evacuation movements without undertaking any other activity;
    1. the occupants recognize that the notification cues indicate that something potentially dangerous is occurring in their environment and as a result undertake a series of Action and/or Information Tasks.

If occupants decide to react following the third point, the activity stage starts. This phase could occur in parallel with the cognition stage and they can affect each other: activities leading to new cognitions and vice versa. So occupants can go and come back between these two stages, they can return to the cognition stage to understand new developments of the situation or interpret new information and change the next course of actions planned. During the activity stage, occupants perform the Action Tasks or the Information Tasks that have developed during the cognition stage. Some examples of Action Tasks can be: shutting down a work station, packing work items, packing/collecting personal belongings in the immediate vicinity, physically moving to another location to perform an action (e.g. fight fire, collect an item). With Information Tasks Galea and colleagues (2010) mean seeking, providing or exchanging information concerning the incident or required course of action and may include, calling someone on the phone to seek or provide information, seeking or providing information in person, engaging with electronic media (e.g. television, radio, text services, etc), investigating the incident. The activity stage starts with the beginning of the planned tasks and ends with their conclusion. The end of the activity stage also marks the conclusion of the response phase and the successive beginning of the evacuation movement phase.

Figure 2 Retreived from Galea et al., 2010

The response phase involves several behavioral aspects like the perception of the incident, the perception of the seriousness of the incident, the disengagement of the person from what he/she was doing, the collection of goods and the investigation of the incident before leaving the building (Gwynne, Galea, Parke & Hickson, 2003).

This response phase produces a delay time in beginning the evacuation process. It can go from a few seconds to some minutes and sometimes the pre-evacuation time is even greater than the actual time needed to evacuate (Gwynne et al., 2003). Predicting this delay is essential to be able to calculate realistic evacuation times. The delay varies according to the type of the alarm system in place, the time of the day, the presence of additional cues that can support the evacuation like instructions or smoke (Gwynne et al., 2003). Moreover, the response delay varies also according to the characteristics of the occupants, the hazard safety features and the type of occupancy (Proulx & Fahy, 1997). Indeed, office and residential buildings are diverse environments and have different characteristics. Differently from residential occupancies, in offices people are usually not responsible for others like children, elderly people or family members in general that need assistance. Working people are capable adults that don’t have to take care of other people and when the emergency alarm rings, they can suddenly start rescuing themselves. Another feature of office buildings is that people are usually awake, dressed and active. For this reason the time needed to start the evacuation is lower. They don’t need to wake up or to get dressed, activities that are more usual if people are resting at home. Moreover, people working in office buildings are usually trained for emergencies. Most of the times they know emergency procedures and regularly receive trainings or do drills, while occupants of residential occupancies don’t. Finally, people working need less time to interpret the cue and understand that is time to evacuate because in the office environment usually it is possible to rapidly observe others and interact with colleagues about how to face the emergency (Proulx & Fahy, 1997).

During the evacuation movement phase occupants perform the actions needed to exit the building. The most important element of this phase is the exit choice. Benthorn and Frantzich (1996) conducted an interesting experiment to test their Theory of Choice by Distance and Familiarity, revealing the preference for the normal exit instead of the emergency exit. This is due to the tendency to choose the known before the unknown, and in case of known routes the familiarity has more importance than the width or length. Moreover, the authors investigated the condition in which, instead, occupants chose the emergency exit: “if the distance to the normal exit was twice the distance to the emergency exit and if that exit was open almost all the persons chose that exit” (Benthorn & Frantzich, 1996, p. 5). What unexpectedly emerged from this study is that people are not aware of the reason of the exit choice, leading the authors to suppose that the decision process was on an unconscious level.

According to Frantzich (as cited by Kobes et al., 2010), the time needed for movement purposes is well documented, meaning that it is possible to measure the time needed to egress different types of buildings and occupants.



Human Behavior in Evacuation: Evacuation


Evacuation from buildings is not only about measuring the time needed to exit or emergency exits’ width. Indeed, actors of the evacuations are human beings that are affected by social and psychological processes that affect the exit from the building.  This chapter will start with a brief explanation about what an evacuation is, of the different classifications used over the times and some information about Italian legislation about evacuation. Then, the two main models of human behavior in evacuation developed by Kuligowski (2008) and Galea, Dreere, Sharp, Filippidis and Hulse (2010) will be presented in detail. Later, some findings from the literature about decision making in evacuation will be reported. Lastly, the final section will provide an integrative model of factors playing a role in the evacuation process.


Evacuation is the primary protective action utilized in large-scale disasters such as hurricanes, floods, tsunamis, volcanic eruptions, releases of hazardous or nuclear materials, and high-rise building fires and explosions. Although often precautionary, protecting human lives by withdrawing populations during times of threat remains a major emergency management strategy” (Sorensen & Sorensen, 2006, p. 183). Evacuation refers to the withdrawal actions of occupants from a building or generally people from a specific area because of a real or potential hazard. The time needed to evacuate can vary from a few seconds to minutes or hours, depending on several factors connected to individuals, hazards and the area’s or building’s characteristics. Nevertheless, speed is the key factor in evacuations: the faster occupants understand the need to evacuate and move quickly to the safe place, the more successful the evacuation will be. Incident analyses have shown that a delayed evacuation results in a larger number of fatalities (Fahy & Proulx, 2001). The first studies about evacuation identified 4 different types of evacuations (Drabek & Stephenson, 1971):

    • invitation – someone outside the area of risk or the building provide the means or urge to leave,
    • choice – individuals processing warning information, deciding to leave and then taking action,
    • default – involves behaviors dictated by actions other than seeking safety from the hazard,
    • compromise – people following orders even if they don’t want to or don’t feel it necessary to leave.

Other authors chose to classify evacuations by crossing two dimension of evacuation: timing and period of evacuation (Perry, Lindell & Greene, 1981). They distinguished between:

    • preventative – pre-impact and short term,
    • protective – pre-impact and long term,
    • rescue – post-impact and short term,
    • reconstructive – post-impact and long term.

Ronchi and Nilsson (2013) categorized the different egress strategies from a building into 4 types:

    • total evacuation – it occurs in case of evacuation of all occupants at once from the building to the designated area of safety. The application of this strategy strongly depends on the use of the building, its characteristics, and the number of occupants.  phased evacuation – when the first strategy is not practical and there is the necessity to control and optimize occupants flow, groups of people can be evacuate in different time, with priority of who is nearer to the hazard (especially in case of fires). This solution works only if there are effective means of communication within the building, trained staff and safety equipment available in the building.
    • defend-in-place – when evacuating is too risky, or in case of people with disabilities, sheltering can be the best strategy. A key aspect in this case is the communication between the rescuers and the rescued that has to be efficient for the operation’s success. ? delayed evacuation – it takes place when evacuees are temporarily waiting in dedicated areas in order to be reached by rescuers. Also in this case, this strategy is useful in case of occupants with disabilities or for health care facilities.

Italian legislation about evacuation considers some norms to manage fire emergencies, exposed in the Decreto Legislativo 81/08 art. 43 DM 10/03/98. It establishes that inside each productive activity, such as factories, offices, plants or public administration, must have an emergency and evacuation plan. This plan is made by both the employer and the RSPP (Responsabile del Servizio di Prevenzione e Protezione, literally translatable in responsible of the protection and prevention service) and must include at least the following points:

    • business activity description,
    • recognition of the persons involved in the emergency management,
    • recognition of the risks connected with the environment or the activity,
    • recognition of the preventive or protective measures present,
    • fire load calculation,
    • fire risk classification (high, medium, low),
    • evacuation manners, ? safe places indication,
    • indication about the fire equipment controls,
    • emergency management, ? drills register.

Italian legislation doesn’t provide special norms for evacuation in case of earthquake, but most of the schools, factories, companies or even trade unions offer special evacuation plan in case of earthquake (for example the document “Linee Guida per la tutela della Sicurezza e Salute dei lavoratori  a seguito di Evento Sismico” from CGIL Pesaro).






After the earthquake occurred in the area of Modena and Bologna provinces (Emilia- Romagna region, Italy) the interest in planning an effective emergency management in evacuation has grown both for residential buildings and for industrial and commercial buildings.

At 4:03 a.m. of May, 20th, 2012, a seismic shock with a magnitude of 6.1 degrees on the Richter Scale occurred at 6.3 km depth in the area of Finale Emilia (Modena province) and it caused the death of 7 people, 4 of which were workers died under the collapse of recently constructed workshop. After that, another strong earthquake occurred at 9 a.m. of May, 29th, 2012 with epicenter between Medolla and Cavezzo (Modena province) with a magnitude of 5.8 on the Richter scale. Several aftershocks hit the area of Bologna, Modena and Ferrara provinces in the weeks after the first seismic event. The amount of the victims rose up to 27 two weeks after the second strong earthquake, and most of the death were workers. The earthquake caused serious damage: structure of historical significance collapsed, as well as lots of residential buildings, factories and firms. The damage of the earthquake was estimated to be of 13 billions and 273 millions of Euros.

After this strong event that also deeply affects Emilia-Romagna’s economy, due to the high amount of victims between workers, the interest in build an effective emergency management in evacuation has grown both for business people and scholars.

In general, Italy is recognized as a seismic area because of its position between the African and Euroasiatic lithospheric plates. Nevertheless, Emilia-Romagna, and in particular the provinces in which the shocks occurred, is classified by the Italian National Institute of Geophysics and Volcanology as a low risk area. The most dangerous seismic areas in Italy are located in the center and in the south of the peninsula. The lack of physical exposure to earthquake has produced the lack of experience in people from Emilia-Romagna, so that they were not ready to manage the emergency.

Research in the field of building evacuation began in the first part of the last century and gained particular momentum since the last four decades (Bryan, 1999; Pauls & Jones, 1980). The first topics of interest have been the movement of people in corridors, on stairs and through doors, but also occupant density and travel speed (Kobes, Helsloot, de Vries & Post,

2010). On the basis of these studies the design and technological measures with which to ensure emergency safety in buildings are nowadays known and used. From the end of the 20th century, the study of evacuation from building become to be a field of study also for social sciences, and also a behavioral perspective was developed.

The empirical understanding of evacuation from buildings is complex and it requires a multi- disciplinary approach, so that several different research areas, such as mathematics, engineering, sociology and psychology are committed in this field of study. Most of the studies about emergency management and evacuation from buildings have focused primarily on calculating and predicting evacuation movements using engineering models, tools and computational simulations. Nevertheless, predicting occupants’ behavior is as important as designing buildings structures to develop a more safety evacuation plan. “Evacuation models are often used in the safety design process in the context of the performance-based design approach. They may be employed both to compare different safety designs as well as define the adequate egress strategies of a building” (Ronchi & Nillson, 2013, p. 6).

“Most of the evacuation simulation models that exist are based upon calculations in which the distance to exits, walking velocity and flow rate capacity of corridors, doors and stairs are decisive. This is the result of prior research, which predominantly focused on these aspects of evacuation. Few simulation models are based on human behavior in evacuation scenarios, such as the preferences for specific routes or exits, or the time needed to gather and interpret the information” (Kobes, et al., 2010, p. 4).

Evacuation models measure evacuation performance by calculating how long it takes for occupants to evacuate a building. Muhdi (2006) has counted 28 different egress models based on the level of complexity in occupant behavior. Most of them are based upon calculations in which the distance to exits, walking velocity and the flow rate capacity of corridors, doors and stairs are decisive. Nevertheless they don’t consider all factors and processes related to human behavior. These models only calculate the time needed to perform each action of the evacuation process, for example standing up, queuing and reaching escape routes. This kind of approach simplifies too much the evacuation process (Kuligowski, 2008). “[…] we know that real evacuation decision making and movement is significantly more complex than water flowing in pipes or snooker balls rolling on a snooker table” (Shields & Proulx, 2000, p. 103). For example, most of the models that try to calculate the time needed to reach the emergency exit assuming that people immediately start evacuating after hearing the warning sound. This is an inaccurate belief and a minimalistic approach that ignores the cognitive, perceptual, psychological and social processes that are associated with evacuation movements, visual access, way-finding and spatial behavior of occupants. Indeed, people need time to understand if the sound they are hearing is really the alarm sound, These models, moreover, don’t consider the pre-evacuation period, that is labeled as “the period from the point when the occupant is notified that there is something wrong until he begins to travel an evacuation route out of the building” (Kuligowski, 2008, p. 7). In that period of time, which occurs before starting evacuation, people interpret the situation and assess the risk. Other models, in addiction, attempt to estimate the number of emergency exit needed according to the structure of the building or the occupants’ number. Such models don’t consider results from previous psychological researches, for example the fact that people under stress tend to choose the same exit used to enter the building (Kobes, Helsloot, de Vries & Post, 2010). Another psychological factor that these models neglect is, for instance, that it is not the actual length of an escape route which determines which way out of a building is chosen, but how it is perceived by the occupants (Kobes et al., 2010).

Luckily, things are changing: “it is now recognized that evacuees are thinking and feeling beings, which react according to factors associated with the past, present and future, and can respond in a multitude of ways to the same incident, either independently or collectively with others” (Schmidt & Galea, 2013, p.12). A comprehensive model of evacuation should be able to predict individual behavior but also group dynamics that are likely to occur during an emergency. Leadership is one of such group dynamics that still has to be investigated to understand his role in emergency management. Some findings in previous researches have demonstrated that it plays a key role accelerating the time needed to evacuate (Gershon, Qureshi, Rubin & Raveis, 2007) or helping other occupants in the interpretation of the situation (Kuligowski, 2008). Nevertheless, other studies are needed in order to identify how the leader should manage the situation, which skills he/she should have, and how the communication leader-members shuld be. What it’s clear is that a leader could be an important resource for an effective emergency management.





A Leader’s Perspective : Abstract



Lo scopo di questo studio pilota esplorativo è stato quello di fare luce sulla leadership come risorsa in casi di emergenza, come l’evacuazione dagli edifici.

Anche se la psicologia ha approfondito la comprensione dei fattori psicologici coinvolti in situazioni di emergenza, ci sono ancora diverse lacune nella letteratura, e la leadership è uno di questi argomenti trascurati.

Così, questa ricerca ha cercato di concentrarsi sugli aspetti legati alla leadership e le relazioni utili a costruire un modello di un buon leader in caso di evacuazione.

I dati sono stati raccolti attraverso un questionario nel mese di ottobre 2012, pochi mesi dopo il forte terremoto che si è verificato nella zona di Bologna e provincia Modena (Italia).

A tale studio hanno partecipato i team leader (37 capi squadra, manager di linea e squadra di primo intervento ) di una organizzazione multiculturale situata nella zona terremotata.

Questo studio fornisce alcuni risultati interessanti circa le variabili che entrano in gioco durante una situazione di emergenza: leadership trasformazionale, conoscenza circa il piano di emergenza, atteggiamento positivo verso di essa, fiducia in se stessi e la risposta della squadra di emergenza.

I risultati mostrano che ci sono correlazioni positive tra le variabili, e che il livello di fiducia in se stessi può essere previsto dal livello di leadership trasformazionale e l’atteggiamento positivo verso il piano di emergenza.

Gli articoli che verranno pubblicati prossimamente sono in lingua inglese.