Fatigue Awareness for Transit
Operations
Transportation Disadvantaged Conference Amber B. Reep
Center for Urban Transportation Research, University of South Florida
Funded by the Florida Department of Transportation’s Florida Transit Training & Technical Assistance Program (RTAP)
www.floridartap.org
Course Overview
• What is Fatigue• Factors that Affect Fatigue• Signs and Symptoms• Types of Fatigue• Driving Affects on Sleep Deprivation• Incidents Related to Sleep Disruption• Strategies to Maintain Alertness
How many hours of sleep did you get last night?
A. 8 or more hours
B. 7 hours
C. 6 hours
D. Less then 5 hours
Why Should We Care about Fatigue?
• 33% of all drivers have fallen asleep at the wheel of something during their lifetime
• 56% of shift workers have fallen asleep on the job
• 55% of adults stated they experienced daytime drowsiness
The Human Toll• 100,000 fatigue related
collisions per year• 1,544 fatigue related
deaths per year
• Imagine:– A Boeing 727 crash
every six weeks
– Titanic sinking once a year
– The World Trade Centers being destroyed every two years
What is Fatigue?
• Fatigue is a complex state characterized by a lack of alertness and reduced mental and physical performance, often accompanied by drowsiness
• Misconception: Fatigue is not just falling asleep
Fatigue Signs and Symptoms
• Forgetfulness• Poor
communication• Impaired decision-
making skills• Lack of alertness• Nodding off• Slow reaction time• Microsleep
• Withdrawn
• Depressed
• Moody
• Quick to anger
• No sense of humor
• Lack of interest
• Always tired
Factors That Affect Fatigue
• Sleep loss and/or disturbed sleep
• Disrupted biological clock
• Excessive physical activity
• Excessive mental or cognitive work
• Monotony or familiarity
• Quality & quantity of sleep
Factors That Affect Fatigue (cont’d)
• Continuous hours of being awake
• Illness• Time of day/circadian
effects• Sleep disorders• Environmental
conditions (hot or cold)• Nutrition
Physical Fatigue
• A decrease in physical performance
• A feeling of muscle discomfort
• Lack of energy
Mental Fatigue
• Tired and drowsy due to loss of sleep• Loss of concentration and/or alertness• Diminished levels of creativity and logic
Accumulating a Sleep Debt
• Sleep loss is cumulative and builds a debt
• Most people get 1 to 1.5 hours less sleep per night than they need
• People whose sleep was restricted to 4 to 5 hours per night for one week needed two full nights sleep to recover vigilance, performance, and normal mood
• How do you get out of sleep debt? SLEEP
Circadian Rhythms
• Circadian rhythms are important in determining the sleeping and feeding patterns of all animals. Patterns of: core body temperature, brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle. – melatonin secretion by the pineal gland and– core body temperature.
Overview of biological circadian clock in humans.This diagram depicts the circadian patterns typical of someone who rises early in morning, eats lunch around noon, and sleeps at night (10 p.m.). Although circadian rhythms tend to be synchronized with cycles of light and dark, other factors - such as ambient temperature, meal times, napping schedule and duration, stress and exercise - can influence the timing as well.
What causes circadian disruptions?
• Shift work• Irregular schedules• Emergencies• Illness• Children• Storms• Telephone• Restless Spouse
Biological and Social Effects on Shift Workers
• 60 to 80% affected by chronic sleep problems
• 4 to 5 times more likely to have stomach disorders
• 80% affected by chronic fatigue
Biological and Social Effects on Shift Workers (cont’d)
• 5 to 15 times more likely to suffer from mood swings and depression
• Divorce and spousal abuse rates higher• Drug and alcohol abuse rates higher
Driving Drowsy Affects Performance Like Driving Drunk
• 19 hours without sleep is similar to a BAC of .05%
• 24 hours without sleep is similar to BAC of .10%
0
0.02
0.04
0.06
0.08
0.1
0 hours 19 hours 24 hours
Pe
rce
nt
(%)
Who’s At Risk?
• People with lack of sleep• Driving patterns
– Midnight till 0600 am– Mid-afternoon– Many miles– Many hours– Monotony
Incidents Related to Sleep Disruption
• Chernobyl 1:23 am• Bhopal 12:40 am• Three Mile Island 4:00 am• Exxon Valdez 12:04 am• Most single vehicle 3-5 am
truck accidents
Incidents Related to Sleep Disruption (cont’d)
• Most mistakes by omission 3-5 am– Surgeon– Nurses– Postal Works– Telephone Operators– Railroad Employees
Counter Measures• Create an optimal sleep environment
– Pillow and Mattress– Bedroom Location– Cool room– Family Ground rules– NO LIGHT– Quite– White noise– Routine
• Strategic naps• Proper nutrition and exercise• Prepare for schedule changes• Readjust your body clock
Supervising Employees
• Do you really notice the operators?• Do you talk to them?• Could you send a fatigued operator home?
Strategies to Maintain Alertness
• Drive defensively• Eat something light on your layover• Physical discomfort
– Heat– Cold– Uncomfortable seat
• Physical fitness• Rumble strips
Be Proactive
• Maintain/encourage healthy life style• Compensate and be aware of shift changes• Understand your bodies sleep needs• Maintain your sleep environment
– Minimize light, disruptive sounds, etc.