Anti Sleep Alarm
A recent study by the Sleep Research Centre indicates that driver fatigue causes up to 20% of accidents on monotonous roads. This suggests that there are several thousand casualties each year in accidents caused by drivers falling asleep at the wheel.
An earlier study of road accidents between 1987 -1992 found that sleep related accidents comprised 16% of all road accidents, and 23% of
accidents on motorways.
Research by the TRL found slightly lower proportions of sleep related accidents: 9% - 10% of accidents on all roads, and 15% of accidents on
motorways involved driver sleepiness. In this study, 29% of drivers reported having felt close to falling asleep at the wheel at least once in the previous twelve months.
An earlier (1984) TRL study9, of 2,000 HGV and PSV drivers involved in accidents, found that driver fatigue was a factor in 11% of these accidents.
In the USA, several studies in recent years have produced various estimates of the level of sleep related road accidents. The National Highway
Traffic Safety Administration (NHTSA) estimate that there are 56,000 sleep related road crashes annually in the USA, resulting in 40,000 injuries and 1,550 fatalities.
One study calculated that 17% (about 1 million) of road accidents are sleep related. A 1995 study suggested that 2.6% of accidents caused by driver inattention were due to fatigue.
A study of road accidents on two of America’s busiest roads indicated that 50% of fatal accidents on those roads were fatigue related. Another study claims that 30% - 40% of accidents involving heavy trucks are caused by driver sleepiness.
An analysis of road accidents between 1990 and 1992 in North Carolina found 5,104 accidents in which the driver was judged to have fallen asleep. This was about 0.5% of all road accidents during that period. A survey of 205 drivers in another State found that 31% admitted having dozed off at least once while driving during the preceding twelve months. Younger drivers were especially prone to doze off, and men were twice as likely as women to fall asleep at the wheel.
VicRoads, an Australian road safety organisation, estimates that 25% - 35% (and possibly up to 50%) of road crashes are sleep related16. A 1994 study, estimated that driver sleepiness accounts for 6% of road accidents, 15% of fatal accidents and 30% of fatal crashes on rural roads.
A study of motorway accidents in Bavaria18 estimated that 35% of fatal motorway crashes were due to reduce vigilance (driver inattention and fatigue).
Between 1996 and 1998, 114 fatal road crashes (8% of all fatal crashes) and 1,314 injury road crashes (5% of injury accidents) were thought to be fatigue related. A study of 370 heavy motor vehicle crashes in 1997, found that driver fatigue was listed as a contributing factor in 7% of accidents.
A questionnaire survey of 9,200 accident-involved drivers found that 3.9% of the accidents were sleep related, but almost 20% of night-time accidents involved driver drowsiness.
An assessment of road accidents between 1984 and 1989 found that up to 1% were recorded as sleep related, but the real figure was likely to be much higher as many accidents recorded as other types of driver error were likely to have been related to driver fatigue.