The Impact of Sleepiness on Accidents
Sleepiness increases attention lapses, slows reaction time and cognitive processing, and makes the drowsy driver as dangerous as one who is impaired by alcohol. This was demonstrated by results from studies with adults who were exposed to extended periods of wakefulness and then subjected to grammatical reasoning and psycho-motor testing. After 24 hours of wakefulness, the subjects’ performance was equivalent to that seen in persons who are legally intoxicated (blood alcohol concentration, .10%). Moreover, fatigue can augment the effects of alcohol and medications. Ingesting 1 oz of alcohol after being restricted to only 4 hours of sleep has the effect of ingesting several alcoholic drinks, resulting in severe impairment.
The National Highway Traffic Safety Administration (NHTSA) estimates that at least 100,000 crashes and 1500 deaths annually are attributable to sleepiness/fatigue. This equates to an automobile accident every 5 minutes and a fatal accident every 6 hours. These crashes alone represent $12.5 billion in lost productivity and property damage. Drowsiness also plays a role in crashes assigned to other causes. NHTSA estimates that another 1 million crashes (1 of 6 of the total) result from driver inattention, and clinical studies show that sleep deprivation and fatigue make such attention lapses more likely to occur. Even the sleep changes that are associated with daylight saving time and during the holiday seasons, with the added stresses of shopping, parties, traveling, and year-end workloads, can result in more accidents.