IAAPA2009 International Association of Amusement Parks and Attractions Human Factors in Amusement Safety What is (are?) Human Factors? Human Factors / Ergonomics (HF) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system in order to make systems compatible with the cognitive, physiological, and anatomical needs, abilities and limitations of people. Human Factors is a young science. Internationally, the oldest scientific societies in the field were established 60 years ago. Early Human Factors proved its value in World War II when controls on the flight deck were redesigned to reduce aircraft and crew losses resulting from control misoperation. Since the early implementation of HF in military and aerospace industries, HF has been applied in a wide range of industries and products from process control to manufacturing and office equipment to vehicles. A common understanding of ergonomics focuses on computer workstations, curvy tool handles, and back injury prevention. Well designed products can be a better fit and more enjoyable to 2009 Kathryn Woodcock :: 1:: use, but there is much more to human factors/ ergonomics than comfort. If we look at the interaction between people, tools, environments, tasks, and the social system around them, we can find and eliminate or mitigate mismatches and improve performance in many more dimensions than comfort alone: enjoyment and satisfaction, efficiency and economy, quality and accuracy, well-being and comfort. When other elements of a system are not designed to accommodate human limitations and make use of human capabilities, people are required to adapt, and people are remarkably adaptable. But whenever there is adaptation, there is the chance that the adaptation will fail. People who are physically overloaded can stretch and strive, but eventually they will become fatigued and inefficient, inaccurate, or even injured. People who are cognitively overloaded can miss the cue that they are supposed to do something, or miscalculate under IAAPA 2009 :: Human Factors in Amusement Safety
Success in amusement is all about human factors : : : Human Factors is an expanding science the strain. The problem is not limited to mismatches that are overloads. In monotonous activities, people are strained trying to maintain attention when nothing is happening. People are clever: when they are strained by overload or bored by monotony, they may try to reduce the need for adaptation by making their own adjustments, but that could cause unintended hazards. For all of these reasons, mismatches between people and other elements of a system lead to outcomes such as discomfort and ill-health, errors, and inefficient performance. The business case for HF is based jointly on improved accuracy and efficiency of performance and user satisfaction while decreasing costs of adverse outcomes. Because of the diversity of human sciences involved in HF from anatomy and physiology to cognition and behaviour it can be difficult for endusers in industry to access relevant research. The goal of this workshop is to improve knowledge exchange between the academic and end-user communities about the application of HF to Amusement Safety. Awareness and use of HF is still increasing and evolving. For example, 15 years ago, healthcare ergonomics focused on prevention of musculoskeletal injuries in patient handling, but current initiatives have expanded to include HF-based strategic intervention to prevent medical error. We can take a broad view of HF in amusement as well. A successful business meets the patron s needs, and amusement is no different. As amusement owners, operators and managers know, amusement is in the mind of the patron. An attraction is only successful if it satisfies the patron s expectation for entertainment and enables them to complete the experience safely. A safe ride that isn t entertaining is not much better than an amazing ride that isn t safe. A human factors approach integrates the entire design including show and theme elements that shape the patron s perceptions about what is going on at the attraction and how they can successfully interact with it. HF considers patron communications that affect which attractions a guest will choose to experience. HF provides insight into the dimensions of the user population and how to physically accommodate them. Of course, guests are not the only humans who must perform successfully for a safe and entertaining experience on the ride. Control interface design is just as relevant to ride and show control interfaces as it is to aircraft flight decks that were improved so effectively 60 years ago. HF has also been applied to support and improve maintenance and inspection tasks in many industries, and has an obvious relevance to amusement, where the diversity of equipment can make these tasks complex and challenging. 2009 Kathryn Woodcock : : 2 : : IAAPA 2009 :: Human Factors in Amusement Safety
How do people interact with things around them? Perception is shaped by the characteristics of things in the environment, and influenced by the observations of other people, and the results of past actions. Perception Action Actions are affected by the physical size, strength, and dexterity of the person and the properties of the things that they can act on. The effect of the person s action depends on how closely it matched the correct or desirable action, and how much tolerance the system has for variability in human action. The person s decision considers goals and values and incorporates knowledge about her own abilities, the rules of the environment, and how to use things in the environment, but is strongly influenced by perceptions. Knowledge can be forgotten, or doubted if it conflicts with perceptions. If perception is inaccurate, a person can make the wrong choice for the best of reasons. Why be frustrated with investigations concluding human error? A HF approach can identify characteristics of equipment, environments and Safe when used as intended? Perception (over) rules! activities that can explain and modify human performance. We need to consider not only whether there were rules and whether patrons had the opportunity to have the knowledge what to do and not do, but more importantly, what influenced their perception that their action or inaction was appropriate? What did they expect would happen? To change behaviour, change perception at the time of the action. Leverage the person s goals and give clues about appropriate actions that will help them achieve their goals. As much as possible, give clues built into the inherent properties of things. A button that looks pushable will be pushed quicker than a spot with a label that says push here. A button that looks pushable will likely be pushed even if there is a label that says do not push here. BETTER AVOID PUSH = GOOD PUSH HERE PUSH = BAD DO NOT PUSH 2009 Kathryn Woodcock : : 3 : : IAAPA 2009 :: Human Factors in Amusement Safety
Human Factors Anthropometry Physiology Uses knowledge from Biomechanics multiple human sciences Perception to examine Cognition the interaction of Motivation The person: the rider, the mechanic, the inspector, the ride operator The machines, materials, and tools the person uses or interacts with The environment where the interaction occurs The social context including roles and rewards The goal-oriented activity being performed New perspectives on lingering questions Why would a guest choose to participate in an attraction incompatible with her physical condition? How would a rider be ejected from a ride with functioning restraints? Why would a guest deviate from posted behaviour rules? Why would a ride inspector approve a ride with deficiencies? Why would a ride operator operate the wrong control or the right control in the wrong way, or at the wrong time? 2009 Kathryn Woodcock : : 4 : : IAAPA 2009 :: Human Factors in Amusement Safety
Human behaviour and error People perform actions of three types: All human error is not alike: Automatic actions: familiar and unconscious. These are the outcome of practice, the key to efficiency, and indeed the hallmark of expertise. We want to encourage correct automatic action, but interrupt automaticity when the grasping the control next to it). situation is not the familiar one. Actions that follow procedures based on the situation the person thinks exists. Success required the person to accurately recognize the was him that needed to do it. situation, recall the rule, remember how to apply it, and of course, for the rule itself to be appropriate. Actions that the person improvises based on the perception of the situation and beliefs about the action results. Success requires accurate knowledge about the environment, equipment, and situation, and enough time to analyse and make the decision. Physical slips: the person had the right intention, but did not execute it accurately (such as tripping, knocking something over when reaching for something else, or activating a control when Lapses: the person should have done something but did not realize it was time to do it, did not realize it needed to be done, or did not realize it Mistakes: the person decided to do (or not do) something based on a misunderstanding of the situation, or a misunderstanding of the effect of the decision, forgetting necessary information, or the choice of an inappropriate goal. Therefore error prevention needs to be customized to the type of error that occurs. We can only do this if we collect that information. Rider behaviour and other mismatches between riders and rides account for the majority of serious reportable rider injuries. For example, in Ontario Canada, the amusement ride accidents that can be classified through investigation by the regulatory agency TSSA consistently comprise about 75% related to human factors, particularly involving patron actions. Over and above these, device failure and other malfunctions can be the result of human performance in design, manufacture, maintenance, inspection, or operation. Warnings Goals Experience Rules Sensations THEN NOW The human cognitive capacity can overflow in high-intensity situations. The intense and immediate input from the senses can squeeze out older knowledge, especially if it conflicts with intuition from goals and experience. 2009 Kathryn Woodcock : : 5 : : IAAPA 2009 :: Human Factors in Amusement Safety
Physical match and physical-cognitive interaction Physical fit is important for comfort and containment of the rider. Ride design standards identify restraint selection for different acceleration conditions, and for young riders. Designers can also use anthropometric data to avoid unintended and undesirable contact between rider and fixed and moving objects, and riders and other guests. HF prefers to design around the vulnerable extremes of the population, as there is no average person. A person who is average in one way can be considerably non-average in other ways. After accommodating as much of the population as we can, we may then limit the allowable users to those who are safely included. Amusement ride height limits attempt to exclude riders who are too young to behave properly. The more we can learn about the relationship between maturity, age, height, and other body dimensions, the more reliable rider height limits will be. Maintenance and inspection Maintenance and inspection can be challenging to learn with the wide variety of amusement devices. Expertise can take years to build. It helps to see a device frequently, but this is not always possible for regulatory inspectors. Due to the physical nature of the work, and sometimes the design of the checklist, checklists are often impractical to use while performing the inspection. Human Factors suggests building reminders and clues into the environment to bridge expertise acquisition, support inspectors with infrequent exposures, and reduce the memory load for all. Providing clear systems models will help the inspector judge whether an observation is a discrepancy. 2009 Kathryn Woodcock : : 6 : : IAAPA 2009 :: Human Factors in Amusement Safety
Human interfaces and ride control Like many types of machinery, amusement device control interfaces are primarily designed to correspond to the electrical and mechanical systems within the ride, not particularly to the ride operator s tasks. Automated modes are often provided that require minimal system knowledge, but in many cases operators must learn, remember, and implement combinations of control inputs for infrequent situations, typically emerging problems when accurate and rapid response is critical. Task-driven control interfaces would reduce the training and improve accuracy compared with circuit-driven interface design. Other amusement interfaces that require similar skill and practice are intended to hinder success! Photo Brian Katt Human Factors to go! A systems designer or manager can make important improvements in performance and well-being through conscious consideration of the needs and characteristics of human users. Most observant designers and managers already know intuitively where the mismatches are. However, the most common response is to remind the users to avoid making errors and to shift responsibility onto the user for accurate performance. Instead, the designer or manager could integrate more user-centred features that inherently reduce errors. Careful consideration of human factors at the right time can reduce the cost of user-centred design to little more than poor design. Individual ergonomic products will reduce specific individual problems such as back fatigue, eyestrain, or wrist pain, but for positive gains in performance, a human-factors analysis needs to examine the whole system, not just purchase components. Designers and managers can use professional advice from human factors engineers / ergonomists (consult directories from national societies such as the Human Factors and Ergonomics Society hfes.org). 2009 Kathryn Woodcock : : 7 : : IAAPA 2009 :: Human Factors in Amusement Safety
Dr. Kathryn Woodcock, P.Eng. Dr. Kathryn Woodcock is an Associate Professor at Toronto's Ryerson University, teaching, researching, and consulting in the area of human factors and ergonomics. Her research interests include the application of human factors/ergonomics to occupational and public safety issues of performance, error, investigation and inspection, and to disability and accessibility. She heads the THRILL lab, established in 2002, which has been researching and developing applications of Human Factors / Ergonomics to amusement ride safety. Dr. Woodcock has taught graduate and undergraduate industrial engineering and ergonomics at Rochester Institute of Technology (New York) and the University of Waterloo (Canada). Outside of academia, she managed accident prevention research and policy in the workers compensation system and for ten years previously was an executive in the health care sector. Dr. Woodcock is a registered Professional Engineer with degrees from University of Waterloo and University of Toronto, a member of national and international professional societies in human factors/ergonomics. In addition to scientific presentations, she is a regular contributor to the Ontario Technical Standards and Safety Authority annual Amusement Device Safety Forum, and has presented on related matters at NAARSO and ASTM F-24 meetings. THRILL Lab School of Occupational and Public Health Ryerson University 350 Victoria Street Toronto Ontario Canada M5B 2K3 For contact information please visit www.ryerson.ca/thrill 2009 Kathryn Woodcock : : 8 : : IAAPA 2009 :: Human Factors in Amusement Safety