Understanding Crowd Dynamics and Management
By Rafael M. Alunan III

In the wake of the Ultra tragedy, I am printing excerpts of articles written by John J. Fruin, Ph.D., P.E., in the hope of providing national and local policy makers and implementors a better perspective of crowd dynamics and management. Knowledge can spell the difference between life and death and disaster avoidance in the future.

The Causes and Prevention of Crowd Disasters

"Crowds occur frequently, usually without serious problems. Occasionally, venue inadequacies and deficient crowd management result in injuries and fatalities. The loss of individual control as well as psychological and physiological problems are some consequences of extreme crowding. A simple model with the acronym "FIST" provides a basic understanding of crowd disasters.

Force: Crowd forces can reach levels that is almost impossible to resist or control. Virtually all crowd deaths are due to compressive asphyxia and not the "trampling" reported by the news media. Forces are due to pushing, and the domino effect of people leaning against each other. Horizontal forces sufficient to cause compressive asphyxia would be more dynamic as people push off against each other to obtain breathing space

Information: In the broad systems sense, information has many forms. It includes all means of communication, the sights and sounds affecting group perceptions, public address announcements, training and actions of personnel, signs, and even ticketing.

Space: The configuration, capacity, and traffic processing capabilities of assembly facilities determine degrees of crowding. Space includes standing and seating areas, projected occupancies, and the practical working capacities of corridors, ramps, stairs, doors, escalators, and elevators.

Time: A simple illustration of timing is the more gradual and lighter density arrival process before an event, compared to the rapid egress and heavy crowd densities after an event.

Crowds occur frequently in modern society: major sporting, religious, entertainment or political events; transportation terminals such as international airports, seaports and train stations; business and exhibition centers; and large shopping malls. Usually large gatherings take place without serious problems. Occasionally, the combination of inadequate facilities and deficient crowd management results in injury and death.

The lethal potential of crowds is illustrated by descriptions of major crowd incidents. This sampling shows that crowd incidents occur in a wide variety of venues and different circumstances. Minor incidents resulting in crowd induced falls and other injuries occur much more frequently.

— Air Raid Shelter. In 1943 during World War II, 173 persons died of compressive asphyxia and 92 injured in a London Underground air raid shelter.

— Funeral Procession. Untold numbers were killed in Moscow during a massive procession of 3 million people viewing the body of Joseph Stalin after his death in 1953.

— Sporting Event Egress. In 1971, 66 people were killed and many injured at the Ibrox Park Stadium in Glasgow, Scotland. In 1981, 24 Greek soccer fans were killed in the Athens stadium. In 1982, 340 people were reported killed at a match in Moscow's Lenin Stadium.

— Sporting Event Ingress. In 1989, 94 persons were asphyxiated and 174 injured at the Hillsborough Stadium in Sheffield, England. In 1985, 10 were killed and 30 injured in a Mexico City incident similar to that at Hillsborough. In 1991, nine persons were asphyxiated in a pileup at the bottom landing of a gymnasium stair at the City University of New York. Police in the street outside the venue did not establish communications with inside security, and were unaware of the evolving disaster, even though the stair could be seen from the street.

— Riot. In 1985 a riot by English and Italian fans in the stands at a European Cup final at Heysel Stadium in Brussels, Belgium precipitated a flight of spectators that resulted in 38 deaths by asphyxia and 437 injured.

— Weather. In 1988 more than 100 persons died and 700 others were injured at Nepal's National Stadium in Katmandu. A sudden violent hailstorm caused 30,000 spectators to flee the open grandstand but found the exit gates were locked.

— Religious Events. Time and again hundreds are killed in a crowd crush during the annual pilgrimage of Muslims at Mecca, Saudi Arabia. In 1986, 46 pilgrims died in Hardwar, India on a crowded bridge across the Ganges River. During the 1980 world tour of the Pope, 13 people were killed in two African cities in crowd rushes.

— Power Failure. In 1981 45 persons died 27 of them children, in the Quitab Minar tower, New Delhi, India. The 800-year-old tower is a popular tourist attraction and museum. A blackout, combined with what some witnesses said were cries that the tower was falling, triggered a sudden exodus of 300 to 400 people.

— Food Distribution. In Bangkok 19 persons died as a crowd of 3,000 assembled to obtain packages of free food. The crowd was attempting to press through a gate approximately 4m (13 ft.) wide into a meeting hall where the food was being distributed. A contingent of 20 police officers assigned to control the crowd was overwhelmed by the crush.

— Entertainment Events. In 1979, 11 young rock music fans were asphyxiated in a crowd crush outside the Cincinnati Coliseum. Only 10,000 could be accommodated by the venue while 8,000 more were still waiting to enter the general admission event. Many were waiting for hours with inadequate lavatory facilities. A warm-up band started playing, and the fans outside thought the concert had begun. Only two doors were opened for entry. In 1991, 3 rock music fans died of compressive asphyxia at a festival in Salt Lake City, Utah. Fans standing in an open area in front of the concert stage pressed forward, causing some to fall, and others to be forced on top of them.

— Escalators and Moving Walkways. In 1964 one child was killed and 60 children injured at the outlet end of a Baltimore, Maryland Stadium escalator. A pileup resulted at the exit, with many severely lacerated by the moving escalator steps. At the 1970 Japanese World Expo, 42 people were injured at a moving walkway exit when someone fell and drove others into the pileup."

Crowd management

"Most major crowd disasters can be prevented by simple crowd management strategies. The primary crowd management objectives are the avoidance of critical crowd densities and the triggering of rapid group movement.

Although the terms crowd management and crowd control are often used interchangeably, there are important differences. Crowd management is defined as the systematic planning for, and supervision of, the orderly movement and assembly of people. Crowd control is the restriction or limitation of group behavior. Crowd management involves the assessment of the people handling capabilities of a space prior to use. It includes evaluation of projected levels of occupancy, adequacy of means of ingress and egress, processing procedures such as ticket collection, and expected types of activities and group behavior.

Crowd control may be part of a crowd management plan, or occur as an unplanned reaction to a group problem. It can include extreme measures to enforce order, such as the use of force, arrest, or threat of personal injury. It may employ barriers that alter the space available for occupancy and patterns of group movement. Inappropriate or poorly managed control procedures have precipitated crowd incidents rather than preventing them. For example, police reacting to a group of unruly persons at a rock concert, herded spectators into areas where there were no means of egress.

Crowd managers must determine a wide range of information about a venue and the people occupying it before a group assembly occurs. Included is an assessment of the nature of the group, experience with similar groups, potential behavior patterns, projected occupancy, facility processing rates, staffing, and means of communication between staff and with the crowd.

Crowds can attract participants who come to observe and to peacefully enjoy the event, predators in search of victims, and people with other psychological or social agenda. Constant monitoring of crowd behavior is necessary for good crowd management. A proactive type of management is required, anticipating and resolving problems before they occur, rather than reacting when it could be too late.

Real time information about the status of crowd conditions in large assembly spaces is critical. A centralized crowd management and communications center should be set up for this purpose. The ideal center should provide a maximum view of the venue, supplemented by video camera access to blind spaces, pressure points, and major movement pathways.

Full communications coordination should be provided between all venue staff, local police, fire, and emergency medical services, and any on-site radio or television media. Radio frequencies, telephone numbers, and similar communications information and related procedures should be in a printed form distributed to all staff.

The training of crowd management personnel is of vital concern. Often casual labor is employed at large events. These employees may only receive vague instructions, usually about controlling certain crowd behaviors. Even permanent staff may have limited training in crowd management, recognition of potentially dangerous crowd problems, and the handling of accidents and other emergencies.

Training should include instructions on the basics of normal and emergency crowd movement and assembly; initial handling of accident victims, altercations and other crowd incidents; communications procedures and use of communications equipment; avoidance of actions that would incite or trigger dangerous crowd behaviors; and conduct and demeanor during an emergency. All personnel should be provided with a quick reference pocket guide to reinforce guidelines and communications procedures.

Response to crowd incidents must be rapid, authoritative, and provide clear and unambiguous information about the emergency and required group actions. Dispersion by multiple routes away from the cause of a crowd incident is preferred over concentrated paths of movement. The summoning of emergency services must be initiated immediately, and not left until the scope of the incident is determined. Victims of compression asphyxia can be revived only if resuscitation begins quickly.

Actions by performers such as late cancellation, walking off stage, encouraging fans to move closer, throwing souvenirs to the audience, or other actions have precipitated inappropriate or hazardous group reactions. Entertainers should be fully informed of their own responsibilities for maintaining order, and the problems associated with inciting potentially dangerous group behaviors. Performers must provide advance notice of cancellation, before patrons begin entering the venue. Communication with the crowd should not be delayed if cancellation occurs after entry. Announcements should clearly establish refund policies, exit routes, and need for orderly movement.

Tickets are an important crowd management information factor. Reserved section and seat tickets determine specific area occupancy, and routes of entry and egress. Tickets also provide a means of instructing patrons on rules of conduct expected within the venue. Major art exhibitions have managed crowding by arrival time ticketing, valid only during a specific time period.

A legal view of crowd management responsibilities requires that crowd participants be informed of foreseeable dangers associated with crowd behaviors and/or assembly facilities.

Litigation proceedings have shown that concert managers are aware that festival seating events cause some to faint from heat exhaustion, and furthermore, that these persons are virtually inaccessible within the crowd. This knowledge requires that crowd participants be warned of crowding hazards, and be instructed in aid procedures.

Architects and engineers typically give minimal attention to the movement of people in initial building design, beyond compliance with local building codes. Code compliance does not guarantee that a building will function well during normal assembly use or emergency egress. Designing for crowd management requires that projected maximum occupancy levels of a space be correlated with the movement capabilities of all corridors, stairs, ramps, escalators, and other facilities.

Designers have the responsibility of preparing the initial crowd management plan as part of the life safety evaluation of a new venue. The plan should establish the assembly and people movement capabilities of all aspects of the venue, movement patterns, identify possible problem areas, and generally describe how the design will accommodate normal and emergency crowd movement. Traffic capacities of corridors, stairs, passenger conveyors, and waiting spaces, have been established by a number of sources.

Access tree diagrams, or schematic line illustrations of pathway configuration, pedestrian volume and direction, are useful planning tools. The tree diagrams show the capacities of doors, corridors, stairs, escalators, landings, and identify pressure and conflict points. Pathway alignments should be simple and direct, and not circuitous or offset from the normal straight line of sight. Arrangements that result in unbalanced use of egress or ingress routes, dead ends, or similar confusing and irregular pathway choices, are not acceptable.

Dispersed and equally balanced ingress and egress points are preferred over a single centralized location. The influence of external facilities on the volume and direction of movement must be considered. Concentration of parking or transit on one side of a venue will focus internal movement towards that side, resulting in unbalanced traffic demands. Architectural statements, aided by directional graphics, should be used to visually define and clarify what processing functions are taking place. Ticketing should be separated from admissions, and the flow between them sequential, uni-directional, and without crossing conflicts.

Pressure points are locations where a change in pathway processing capacity, normal directions of movement, or a confluence of traffic streams, results in conflicts or accident exposure. Examples include directional changes where there are inadequately guarded openings to lower levels, at stair approaches, and landings at the discharge or outlet ends of escalators. Crowd pressures at such locations have resulted in people being pushed over guardrails, down stairs, or in structural failure of guardrails.

Alternative power sources for lighting and communications are required. The New Delhi tower museum crowd incident is an example of the confusion resulting from a combined lighting and communications failure. A public address system tied to only one source could be lost when most needed.

Emergency room space and equipment sufficient to handle routine accidents and larger crowd incidents is required. Lives have been unnecessarily lost in large crowd incidents by the lack of simple equipment such as stretchers and oxygen. Many venues accommodate the population equivalent of a medium sized city, requiring that the medical centre be equipped to provide skilled response to cardiac, spinal injury cases and other emergencies. Means of communication with local emergency medical services, their response times and ability to handle a mass crowd disaster should be established as part of the crowd management plan.

The rationale for time based crowd management strategies is the control of pedestrian demand rates so that traffic flow does not exceed the capacity of any element of the venue. The objective of temporal strategies is to keep pedestrian densities below critical levels. Restaurant reservations and the arrival time ticketing method used for museum exhibits are familiar examples of time based crowd management.

It may be necessary to meter, or throttle the arrival rate demand at facilities with limited processing capacity. Examples could include stairs, narrow corridors, escalators, ticket gates, pressure points, or other locations where excessive arrivals will cause hazardous overcrowding. Metering must be carefully applied because it will cause waiting lines and crowding on the approaches to the metered facility. The approach area should be large enough to accommodate expected demands and to establish formal queue lines. Communication is a critical aspect of metering control. Personnel involved in the metering operation should be in constant communication with each other and alert to any interruptions in flow.

Early opening of a venue to extend the ingress arrival process, and post event entertainment or other strategies to lengthen the egress process, reduces crowding within the venue and traffic pressures on external transit, road, and parking facilities."

Conclusions

"The crowd incident model and its derivative guidelines show that many crowd disasters could have been avoided by simple advance planning and management techniques. Reliable real-time communication between those responsible for crowd management, and authoritative communication with the crowd, are also critical elements in defusing a potentially lethal crowd incident. These strategies are also the least costly means of preventing crowd disasters.

Crowd managers have an awesome responsibility for the safety of large numbers of people. Yet there is little formalized training in crowd management principles and techniques. Police training focuses on crowd control, and not generally on crowd management. It is recommended that every venue accommodating more than 500 persons be required by law to have a certified crowd manager on staff. In order to become certified the candidate would undergo formalized testing on the basics of crowd management and handling of emergencies."

The Ultra tragedy could have been avoided but it seems that on February 4 and the days preceding it, poor crowd management and control, delayed responses and delayed emergency management combined in a deadly mix that resulted in over 70 dead and 600 injured. Whether local authorities, events organizers and venue managers will learn from this tragic lesson remains to be seen given the long trail of tragedies that have struck the Filipino soul time and again.

In time, a full report will be rendered and accountabilities will be held. From the looks of it, there is enough blame to be shared by everyone concerned. Despite efforts to hide its share of culpability, the local authorities of Pasig will have much to answer for, in much the same way that they will have to explain why a shabu "restaurant" had been operating for years under their very noses.

It is horror stories about repeated mindlessness, incompetence and criminal negligence of public duties that drive erstwhile normal and peaceful people to lose their equanimity and consider extra-legal means to drive out entrenched public service failures permanently out of their lives. Frankly, it truly amazes how the Filipino can absorb so much punishment and be so forgiving. It is both a blessing and a curse.

And if claims are true that the Filipino has had enough and is willing to silently give his blessing to what whisperers say will be a "constitutional rescue" — whatever that means — it becomes tempting, in sadly distressing times like these, to send word to "them" that it is their sacred obligation to emerge victorious and ensure that real change gets underway. Otherwise, we will have a bigger tragedy in our hands. ***