Question of the Week

April 17, 2006


Everything was working as it should. There was nothing wrong with the ride. Yet, if the ride was functioning properly, then why did it end in tragedy?

"Thu Apr 13, 2006 9:10 PM BST ORLANDO, Florida (Reuters) - A 49-year-old German woman died after riding a rocket simulator at Walt Disney World's Epcot theme park in Florida, the second person to die in less than a year after riding on Mission: SPACE, state officials said on Thursday. State regulators said Disney had told them the woman, who died Wednesday evening, may have had some prior health problems including high blood pressure and chronic headaches. ... The attraction uses spinning centrifugal force to create the sensation of a rocket launch. 'They didn't see anything out of the ordinary ... Disney was satisfied that it was behaving normally.' Mission: SPACE reopened to the public on Thursday morning, Disney said in a statement. In June 2005, 4-year-old Daudi Bamuwamye of Pennsylvania died after riding Mission: SPACE with his mother and losing consciousness. An autopsy by a Florida medical examiner's office determined that Bamuwamye had an undiagnosed heart defect which put him at risk of sudden death under stress. Mission: SPACE was inspected by Disney after Bamuwamye's ride, found to have no mechanical problems and also reopened the following morning."
Reuters News

Two cases of illness -- at least one of which was undiagnosed -- that ended in death when combined with a ride. How is it that a ride that is working as it should would cause such problems for its riders?

"The thrill of a good roller coaster: you hold your breath, your hair blows in the wind, and your heart races as you speed along the track. A report in an issue of Neurology (January 11, 2000) suggests that some giant roller coasters can do even more...they may cause the brain to bleed and the blood to clot in what is called a subdural hematoma. A subdural hematoma is caused by the rupture of blood vessels near the surface of the brain. Blood gets trapped between the meninges (coverings of the brain) and the brain. The hematoma causes pressure on the brain, which may cause headaches and vomiting."

With all the possible medical concerns,

"Many people wonder whether coasters are safe. ... From a physics standpoint, coasters are quite safe. For instance, in an inversion, the forces always conspire to keep the rider in the car. Coaster designers calculate the forces on the coaster to make it feel dangerous, but really be quite safe. However, these calculations are done assuming the rider does nothing unusual. If you stand up in a sit-down coaster, the designer's calculations will no longer apply. Then, negative G's may be enough to eject you. On a curve, your center of gravity may end up above the side of the car, and you will be in serious danger of being thrown out. If treated with respect, coasters are quite safe. The chances are very slim that you will be hurt on a coaster if you ride it correctly. If you do something foolish, though, you greatly increase your chances of injury."

Rides are designed to offer fun by pushing the limits in a controlled environment. With so many variables, it is difficult to completely control any environment...

"Complex Rides + Complex Humans = Complex Safety Issues
* Millions of patrons visit amusement parks and carnivals in the United States each year. ...
* Injuries range from stubbed toes and bruised knees to death and dismemberment.  Because of the strong forces exerted by the machinery, the extent of injury from an amusement ride accident is often a matter of luck.  If a
rider is tossed into a bush, for example, he might walk away without injury. But if that same rider is ejected into a wall, the outcome will be far more serious. The causes of ride-related injuries, and the strategies for preventing them, are equally diverse. ...
Common Causes of Ride-Related Injury
* Youth and Inexperience
* Water Slides, Go-Karts, and Other Patron-Directed Rides
* Patron Daze, Wiggle Worms, and Horseplay
* Size Mismatch Between Patron and Ride
* Intensity of Motion and Emotion
* Equipment Failure
* Operational Issues
* Sales vs. Safety:  Conflict Between Marketing Message and Reality
* Ride-Specific Risk Factors"

There are so many variables. There are so many issues to take into consideration. Riders need to know what the rules are for each ride; and they need to know why those rules are there in order to know how those rules pertain to their lives.

"Thursday, 10 January, 2002... CPSC figures show injuries on fixed-site amusement parks increased by 95% between 1996 and 1999, while attendance only increased by 6.5%. They estimated the risk of sustaining an injury which needed hospital treatment was one in 15m rides, and the risk of being fatally injured was one in 150m rides. During the past 10 years, there have been 15 reports in medical literature of life-threatening brain injuries caused by riding rollercoasters. Several of the authors of these reports have said giant roller coasters produce enough G-forces to cause brain injury. Potential head injuries include subdural haematoma, a serious injury characterised by blood under a membrane surrounding the brain. Rides could also cause other health problems including seizures and back injuries. The researchers of this latest study believe federal legislation passed in 1981, which exempted large, fixed-site amusement parks from reporting injuries or undergoing accident investigations by the CPSC, led to the actual number of injuries per year to be underestimated."

Rides and riders are abundant. Injuries are few (as a percentage of total ridership), and vary greatly in severity. That said, there are still many variables to consider. Machines can malfunction, but even when they are working perfectly there can be tragedies. Ride operators can make mistakes or fail to complete all safety check. Riders sometimes choose not to follow the rules, and sometimes don't know the limitations of their own bodies.

"Human error is always a concern when devising machinery to be used by humans. Accepted theory suggests that systems be designed to provide error prevention, error capturing, and error tolerance. Woodcock and Tsao found that each of these is present in amusement rides, and each may also fail:
* Ride designers and owner/operators furnish certain error prevention mechanisms (restraints, warnings signs to deter certain behaviors and promote safe behaviors)
* Safety margins in ride design, installation, and operation help ensure a high degree of error tolerance .
* Ride operators perform error capturing functions such as enforcing height limits, guiding guests during load/unload, checking restraints, monitoring for unusual conditions, and performing an emergency stop if necessary. Woodcock and Tsao make the point that 'operator's vigilance is not a perfect "antidote" for rider error ... In addition, operators themselves may make errors.' "

Questions of the Week:
What do people need to take into consideration when deciding which rides to enjoy? How is this different for different people? What do you need to know about your own health when making that decision? What are the responsibilities of the park and the employees to keep the rides safe for those who ride? What responsibilities do the riders have? What would you say to someone who is not concerned because, "These accidents are rare; it could never happen to me"? What would you say to someone who won't ride any rides because, "They are too dangerous"?

Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.

I look forward to reading what you have to say.

[email protected]
Health Community Coordinator
Access Excellence @ the National Health Museum

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