Transcript TRUCK DRIVER ALERTNESS - Texas Association of

Defining the problem
 To reduce fatal crashes between
trucks and other vehicles, a study was
conducted to identify when most of
the fatalities are occurring and under
what circumstances.
Who’s at “FAULT” in fatal
accidents involving trucks &
other vehicles
 OTHER DRIVER AT FAULT = 71%
 TRUCK DRIVER AT FAULT = 16%
 BOTH DRIVERS AT FAULT = 11%
 NO ONE AT FAULT = 2%
Truck Crash Statistics
In two-vehicle fatal crashes between
large trucks and passenger cars,
• 7% of the truck drivers were under 26
years old
• 2% were over 65
• Less than 1% had a BAC of 0.10% or
greater
Operator Fatigue
A significant number of
vehicle accidents are caused
by
• Driver Fatigue
• Loss of Alertness
• Poor Performance at the
Controls
Fatigue-Related Accidents Cause
• Fatality or severe injury
• Loss of corporate revenues
• Lower productivity
• Place operator’s privileges at risk
• Significant company liability exposure
Operator fatigue, is a state of mind
and body, a response to continued
physical or mental activity or
sleep loss, is characterized by
diminished ability to work, loss of
attention, slower reactions, poor
response, deterioration of attention
or alertness, & impaired judgment.
Fatigue can be caused by
combinations of inadequate
rest, sleep loss and/or disrupted
sleep, displaced biological
(circadian) rhythms, excessive
physical activity or mental
work, and general
psychological stress.
Physical Fatigue
… a temporary loss of muscle
power to respond to demands
…a feeling of tiredness,
soreness, or discomfort
…physical performance
declines
Mental Fatigue
… a feeling of tiredness after
extended or repeated tasks…
particularly non-physical tasks
such as driving
…may include feeling of monotony
or boredom caused by lack of
varied stimulation.
Mental Fatigue
… negatively affects your
level of alertness at the
wheel & leads to poor
driving performance
Chronic Fatigue
… a short term condition that can
be relieved by adequate rest and
sleep; usually we can recover
full alertness in just a few days
with longer sleep (Sleeping
longer on weekends, etc.).
Chronic Fatigue
… results from repeated and
cumulative stress… some
refer to it as “Burnout”
…may require extended
break… several days off
Operator Fatigue Factors
….Quality & quantity of rest or sleep
….Individual physical fitness
….Individual endurance to demanding tasks
….Environmental conditions of heat,
humidity, cold, altitude, etc.
….Performance on sustained work suffers
before that on intermittent tasks
AND
Types of Tasks, Time-of-Day, Personal
Motivation & Individual Differences
Operator Fatigue
Sleep requirements differ for
individual persons, and vary
with age (infants,
adolescents, young adults,
mid-aged adults, seniors).
Operator Fatigue
Most adults maintain normal
alertness, perform near their
best, by obtaining 7- 8 hours
of uninterrupted sleep every
24 hours.
Operator Fatigue
Some people get by with less
sleep (5-6 hours) but often
augment this sleep with naps.
Others think they can get by with
less sleep, but in reality, if their
performance were measured it is
degraded.
Sleep Structure
Normal nighttime sleep involves 4-5
repeated 90 minute cycles of brain
electrical activity (coded into 5
sleep stages) as we restore ourselves
to a refreshed, alert state, or we
recuperate from sleep loss and
fatigue.
Sleep Structure
Rapid eye movement (REM)
or dream sleep and slow
wave sleep (stages 3 & 4 are
deep sleep) seem to be the
most recuperative.
Continuity of Sleep
A period of 4+ contiguous hours
of sleep permits several
uninterrupted 90-minute cycles.
Eight 1-hr sleeps are not the
equivalent to a full 8-hrs of
sleep. Intermittent, broken sleep
is usually detrimental to
alertness.
Sleep Loss or Sleep Debt
When we miss sleep required to
maintain normal alertness, we
accrue a “SLEEP DEBT” which
accumulates each successive 24-hr
day we shortchange ourselves of
anticipated sleep (obtaining only 5
hrs one night minus our required 8
nets 3-hr sleep debt).
Sleep Loss or Sleep Debt
If after several days our sleep
debt accrues to 10-12 hrs
sleep debt (more than one
night’s sleep loss) we begin
to perform as if we missed
an entire night’s sleep.
Recovery Sleep
Paying off a sleep debt
usually does not require
a 1-for-1 replacement of
hours missed sleep.
Recovery Sleep
A “tired” brain quickly goes
into a sleep stages 3 &4
which makes efficient use
of the first long duration
sleep period
Recovery Sleep
Consequently, we spend a
shorter time in the less
restorative sleep stages (1 &
2), but more time in states
3, 4 and REM sleep
Recovery Sleep
After weekly sleep debt of 15+
hrs we might make up a debt
with one or two long
duration recovery sleeps
(10+ hrs) on the weekend.
Rest Breaks
Rest may be a break in activity,
or simply a change of pace or
even a change in activities.
Rest breaks permit us to restore
our energy, break the
monotony, or give our bodies
and minds relief.
Rest Breaks
Frequent Rest Breaks Can Be
Helpful in Any Sustained
Work.
But Rest Is Not the Same As
Sleep,
And It Will Not Substitute for
Needed Sleep.
Circadian Rhythms
… our physiological &
behavior patterns repeat daily
in synchronization with our
internal biological clock.
Circadian Rhythms
…body core temperature,
urine production, hormonal
excretions, digestive
processes etc…. Repeat at
the same time each day.
Circadian Rhythms
…as we wake up from a
night’s sleep, our body
temperature begins
increasing, and gradually
rises through the day until
about 1 to 3 PM when it
levels off somewhat.
Circadian Rhythms
… being awake past mid-night
after no sleep results in feeling
groggy, less alert, and
performance is considerably
degraded in this circadian low
period (midnight to 4 AM)
when our brain would prefer to
be asleep.
Performance Implications of C-R
…best time to obtain sleep is
during the C-R lows (afternoon
siestas or naps are valuable).
…if you cannot sleep during the
C-R lows, taking a rest break
will be beneficial
Work Shift Changes
…sleeping, working, and eating
meals on a new schedule requires
a period of from one to three
weeks for the body to adjust to the
new rhythm, a period during
which the worker is likely to
experience “Shift- Lag” much like
trans-meridian travelers
experience “Jet Lag”.
Work Shift Changes
… forward shift rotations are
easier than backward
rotations.
… as an example, it is
generally easier to adjust to
flying westward by staying
awake longer that day.
Keep In Mind
…sleepiness and fatigue can
be a serious threat to safe
vehicle operation.
…fatigue is physiological and
can be can be affected by
our psychological factors.
Keep In Mind
… plan ahead to get enough
sleep
… be aware of the “brain &
body” principles of fatigue
and sleep loss
Keep In Mind
…plan ahead, both at home,
and on long trips,
…implement fatigue
countermeasures