July 15, 2009 | Barb Carr

Transportation Fatality Incidents: Was it Fatigue? What is a Sleep Disorder? What is Day Time Sleepiness?

Trolley crash last year in Boston killing the operator. After 14 months of investigation the NTSB faulted the operator for ignoring a red signal along the tracks but directed harsh criticism at the Massachusetts Bay Transportation Authority which operates the train system. Here are a few findings that make you think…..

…likely had a sleep disorder and fell into a “micro-sleep” shortly before the collision

…the NTSB’s conclusion that Edmonds fell asleep is partly conjecture, the board acknowledged.

…concluded there was a “high likelihood” that Edmonds had an undiagnosed sleep disorder

…. she was obese and had doxylamine in her system

…there is a lack of other evidence to explain why Edmonds failed to slow or stop the train, the board concluded

A few suggestions based on the above findings….

The transit authority failed to screen operators for sleep disorders while enforcing a work schedule that could prevent train operators from getting enough sleep, the NTSB said.

The board also noted that the MBTA had not installed systems on its Green Line to prevent two trains from occupying the same stretch of track, the NTSB said.

Some confounding facts…

Edmonds, a part-time trolley operator, had an opportunity for adequate sleep the day of the wreck, although investigators were not able to determine her sleep history.

In addition, Edmonds had been given a break earlier in the day, had not complained to co-workers about fatigue and was found to be free of drugs and alcohol.

“We cannot say for certain that she did have it (sleep apnea),” board member Dr. Mitch Garber said.

What’s wrong with this picture? Based on an investigation of I don’t know and conjecture we have a finding that the company should have tested for Fatigue and Sleep disorders for their operators.

Micro-sleeps are brief, unintended episodes of loss of attention associated with events such as blank stare, head snapping, and prolonged eye closure which may occur when a person is fatigued but trying to stay awake to perform a monotonous task like driving a car or watching a computer screen.

You do not need to have a sleep disorder to have micro-sleeps occur but it is not the same thing as day time sleepiness. So if the Governing body of Safety is telling you should have tested for sleep disorders and set up schedules that reduce micro-sleep what do you do? What is the recognized tool to evaluate Fatigue that is correlated with NTSB findings? How should you set up your schedules to reduce fatigue?

TapRooT® can guide you through these questions BEFORE the NTSB tells you do it by attending our Stopping Human Error Course.

The main focus of the course is on practical solutions to the most common industrial and service industry causes of human error. Fatigue solutions and a recognized measuring tool will be introduced along with many other types of human error needs. We know about these problems because we see them in TapRooT® Classes around the world.

Our next class is in Nashville October 5-6. We offer this class one time a year so this is your chance to register before it fills up.

http://www.taproot.com/summit.php?t=pre-summit#humanerrorSee the CNN article: “Sleep disorder may have contributed to Boston train crash”, http://www.cnn.com/2009/US/07/14/ntsb.train.crash/index.html

A definition of Micro-Sleep link: http://www.sleepdex.org/about.htm


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