Last year driver fatigue caused one in five fatal crashes on our
roads. From a momentary loss of concentration to feeling tired or
sleepy, driver fatigue can lead to losing control of your vehicle. The
risk of a fatal fatigue crash is four times greater between 10pm and 6am
than for the rest of the day.
Fatigue is a general term commonly used to describe the experience of
being "sleepy", "tired" or "exhausted". Fatigue is both a physiological
and a psychological experience.
Driver fatigue can severely impair judgment and can affect anyone. It
is particularly dangerous because one of the symptoms is decreased
ability to judge our own level of tiredness. Other symptoms vary between
drivers, but may include:
yawning. poor concentration. tired or sore
eyes. restlessness. drowsiness. slow reactions. boredom. feeling
irritable. making fewer and larger steering corrections. missing road
signs. having difficulty in staying in the lane. micro sleeps.
It is
important to note that driver fatigue is not simply a function of time
spent driving but relates to many factors including hours since last
slept (hours of wakefulness) and time of day or night.
When?
High risk times for fatigue-related fatal crashes are:
Night-time/early morning
10pm-6am
Afternoon
1pm-3pm
Fatigue-related crashes at these times of the day coincide with dips
in the body's circadian rhythms, which program us to feel sleepy at
night when we would normally be asleep and to a lesser extent in the
afternoon hours.
Fatal crashes identifying fatigue as a factor are more likely to
occur during public and school holiday periods. Nearly 30 per cent of
all fatal fatigue accidents occur during public or school holidays.
Where?
Most fatigue-related crashes occur on country
roads. In 1998-2002, 79 per cent of fatigue-related fatal crashes
occurred on country roads.
Fatigue-related crashes also occur in urban areas. In 1998-2002, 21
per cent of fatigue-related crashes occurred on urban roads in Ireland.
Of all fatal crashes where fatigue was identified as a factor, 37 per cent involved head on collisions.
Driver Reviver / Rest Areas
To help reduce driver fatigue,.
STOP, REVIVE, SURVIVE
Rest areas are places where you can park safely, get out of your car
and refresh yourself before continuing your journey. Rest areas are
available 24 hours a day, all year round and are clearly
signposted. Service centres, petrol stations, parks and country towns
are other places you can stop and take a break from driving. Micro sleep
A microsleep is a brief and unintended loss of consciousness
characterised by head snapping, nodding or closing your eyes for more
than a couple of seconds. Microsleeps occur when you try to stay awake
to perform a monotonous task such as driving.
Micro sleeps can last from a few seconds to several minutes and often people are not aware that a micro sleep has occurred.
During a 4 second microsleep a car travelling at 100km/h will go 111 metres while completely out of the driver’s control.
The sleep & wake cycle
The best way to prevent driver fatigue is to make sure you have
enough sleep before driving regardless of the length of your trip. There
are 3 sleep factors to consider before deciding whether or not to start
driving.
1. Circadian rhythms
Circadian rhythms are physiological cycles that follow a daily
pattern. We are "programmed" by our circadian rhythms to sleep at night
and to be awake during the day.
During night time hours and to a lesser extent during afternoon
"siesta" hours, most types of human performance are significantly
impaired, including our ability to drive.
Problems occur if we disrupt our natural sleep cycles (eg by staying
awake during the night), do not get enough sleep, or get poor quality
sleep.Circadian rhythms cannot be reversed. Even if you have been
working nightshifts for many years, your body will still be programmed
to sleep at night.
2. Sleep debt
The human body requires a certain amount of sleep each night to
function effectively. The average amount of sleep a person needs is 8
hours. When we reduce the number of hours we sleep at night we start
to accumulate what is called a 'sleep debt'.
Sleep debt is defined as the difference between the hours of sleep a person needs and the hours of sleep a person actually gets.
For example, if a person needs 8 hours of sleep per night but only
gets 6 hours of sleep one night, they have a sleep debt of two hours.
These lost hours of sleep need to be replaced.
When we have sleep debt, our tendency to fall asleep the next day
increases. The larger the sleep debt, the stronger the tendency to fall
asleep.
Sleep debt does not go away by itself. Sleeping is the only way to reduce your sleep debt.
3. Sleep inertia
Sleep inertia is the feeling of grogginess after awakening and temporarily reduces your ability to perform even simple tasks.
Sleep inertia can last from 1 minute to 4 hours, but typically lasts 15-30 minutes.
The severity of sleep inertia is dependent on how long you have been asleep and the stage of sleep at awakening.
Effects can be severe if a person is very sleep deprived or has been
woken from a deep sleep stage. However, sleep inertia can usually be
reversed within 15 minutes by activity and noise.
Sleep inertia can cause impairment of motor and cognitive functions and can affect a person's ability to drive safely.
Sleep inertia can be very dangerous for people who drive in the early morning hours and shortly after waking up from a sleep.