Defining the problemDefining 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 “Who’s at “FAULTFAULT” in fatal ” in fatal accidents involving trucks & accidents involving trucks & other vehiclesother vehicles

OTHER DRIVER AT FAULT = 71%TRUCK DRIVER AT FAULT = 16%BOTH DRIVERS AT FAULT = 11%NO ONE AT FAULT = 2%

Truck Crash StatisticsTruck 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 FatigueOperator FatigueA significant number of

vehicle accidents are caused by • Driver Fatigue

• Loss of Alertness

• Poor Performance at the Controls

Fatigue-Related Accidents Cause 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 FatiguePhysical Fatigue… a temporary loss of muscle

power to respond to demands

…a feeling of tiredness, soreness, or discomfort

…physical performance declines

Mental FatigueMental 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 FatigueMental Fatigue

… negatively affects your level of alertness at the wheel & leads to poor & leads to poor driving performancedriving performance

Chronic FatigueChronic 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 FatigueChronic Fatigue

… results from repeated and cumulative stress… some refer to it as “Burnout”

…may require extended break… several days off

Operator Fatigue FactorsOperator 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

ANDAND

Types of Tasks, Time-of-Day, Personal Motivation & Individual Differences

Operator FatigueOperator Fatigue

Sleep requirements differ for individual persons, and vary with age (infants, adolescents, young adults, mid-aged adults, seniors).

Operator FatigueOperator Fatigue

Most adults maintain normal alertness, perform near their best, by obtaining 7- 8 hours of uninterrupted sleep every 24 hours.

Operator FatigueOperator 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 StructureSleep 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 StructureSleep 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 SleepContinuity of SleepA 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 DebtSleep Loss or Sleep DebtWhen 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 DebtSleep 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 SleepRecovery Sleep

Paying off a sleep debt usually does not require a 1-for-1 replacement of hours missed sleep.

Recovery SleepRecovery Sleep

A “tired” brain quickly goes into a sleep stages 3 &4 which makes efficient use of the first long duration sleep period

Recovery SleepRecovery 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 SleepRecovery 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 BreaksRest BreaksRest 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 BreaksRest 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 RhythmsCircadian Rhythms

… our physiological & behavior patterns repeat daily in synchronization with our internal biological clock.

Circadian RhythmsCircadian Rhythms

…body core temperature, urine production, hormonal excretions, digestive processes etc…. Repeat at the same time each day.

Circadian RhythmsCircadian 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 RhythmsCircadian 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-RPerformance 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 ChangesWork 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 ChangesWork 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 MindKeep 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 MindKeep In Mind

… plan ahead to get enough sleep

… be aware of the “brain & body” principles of fatigue and sleep loss

Keep In MindKeep In Mind

…plan ahead, both at home, and on long trips,

…implement fatigue countermeasures