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.

Whos at FAULT in fatal accidents involving trucks & other vehicles ë OTHER DRIVER AT FAULT = 71% ë TRUCK DRIVER AT FAULT = 16% ë BOTH DRIVERS AT FAULT = 11% ë 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 operators 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 & leads to poor driving performance … 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 tasksAND 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 hrs sleep debt (more than one nights sleep loss) we begin to perform as if we missed an entire nights 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 nights 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