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Sleep is an essential part of life. Insufficient or
non-restorative sleep has detrimental consequences for health, work
performance, mood and motivation. Excessive daytime sleepiness (EDS)
is manifest in a population not experiencing deep restorative sleep.
EDS may be the consequence of short or long-term sleep deprivation
common in shift-workers or busy truck drivers who drive long, monotonous
routes and face deadlines. Regardless of its cause, EDS has potentially
serious consequences for these individuals as the risk of having a
road accident is dramatically increased.
Road traffic injuries in developing countries particularly affect
the productive (working) age group (15-44 years) and children. (A
developing country is defined as a country that has an annual per
capita gross national product (GNP) less than US$9361 (£6456),
based on 1998 figures from the World Bank. Most low and middle income
countries fall into this category.) Globally, in 1998, 51% of fatalities
and 59% of disability adjusted life years lost due to road traffic
injuries occurred in the productive age group. Fatality rates among
children are especially high in developing countries, as shown in
fig 2. In 1998 the fatality rate for children aged 0-4 years was
29.5 per 100 000 population in South East Asia and low income countries
of the western Pacific region, compared with 4.5 deaths per 100
000 population in high income countries. For older children, aged
5-14 years, the fatality rate was 28.1 per 100 000 population in
Africa compared with 4.8 for North America, western Pacific countries,
and high income countries in Europe.
Sleepiness in drivers is known to be an important factor contributing
to motor vehicle accidents and injuries. Published estimates of
the contribution of sleepiness to accidents vary considerably. In
the United States 6% of all vehicle accidents are thought to be
sleep related, in the UK 20%, in France the figure is 10% and in
Australia it is 33%. In a survey, conducted in South Africa, 25%
of truck drivers admitted to being involved in an accident as a
result of sleepiness and up to 37% of all road fatalities may be
attributable to driver sleepiness.
South Africa has one of the highest road accident death rates in
the world! The number of fatalities on South African roads has risen
from 7260 in 1998 to more than 10,000 in 2004 i.e. 10 Times the
number of Deaths compared to the UK! Applying data from the USA,
UK and SA and other countries, we can predict that driver sleepiness
was a factor in about 4000 of these fatalities. Of these 4000 sleep-related
fatalities, about a 1000 are directly related to Driver Fatigue
and Sleepiness.
Factors associated with Sleep Related Vehicle Accidents
(SRVA)
The Institute for Traffic Management and Research in New
York has identified the following five factors as the essential
factors contributing to long-haul drivers falling asleep at the
wheel:
| 1. |
Driving Schedule -driving performance among truck
drivers declined with an irregular schedule, more than 8 hrs
of driving for regular schedules, and more than 5 h of driving
for irregular schedules; |
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| 2. |
The time of day is predictive of sleepiness-related
driving among truck drivers -The US-Canadian Driver Fatigue
and Alertness Study found that the strongest and most consistent
factor influencing driver fatigue and alertness was time of
day, rather than time on task or cumulative number of trips; |
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| 3. |
The quantity and quality of sleep - a person’s
tendency to fall asleep during normal waking hours is increased
and psychomotor performance declines with fewer hours of sleep
and successive days of restricted sleep; |
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| 4. |
The Presence of Obstructive Sleep Apnoea (OSA)
A condition of interruptions or pauses in breathing whilst asleep
– signs of this disorder include obesity, snoring, sleep
interrupted by intermittent gasping for breath, and excessive
daytime sleepiness. |
Groups at high risk of causing Fatal SRVA’s:
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Young Drivers |
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Commercial Drivers / Shift Workers |
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Drivers who consume Alcohol and/or Drugs |
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Drivers with Sleep Disorders particularly OSA |
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Drivers with other Medical Disorders |
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