Dealing with fatigue

NHTSA data indicates that in recent years there have been about 56,000 crashes in the US annually in which driver drowsiness or fatigue was cited by the police. Annually, an average of roughly 40,000 nonfatal injuries and 1,550 fatalities resulted from these crashes. Sleep is a neurobiological need with predictable sleepiness and wakefulness.

The loss of one night's sleep can lead to extreme-term sleepiness, while habitually restricting sleep by 1 to 2 hours a night can lead to chronic sleepiness. Sleeping is the only way to reduce sleepiness. Sleepiness causes auto crashes because it impairs performance and it can ultimately lead to the inability to resist falling asleep at the wheel. Critical aspects of driving impairment associated with sleepiness are reaction time, vigilance, attention and information processing.

Subjective and objective tools are available to approximate or detect sleepiness. However, unlike the situation with alcohol-related crashes, no blood, breath or other measurable test is currently available to quantify level of sleepiness at the crash site. Although current understanding largely comes from inferential evidence, a typical crash related to sleepiness has the following characteristics:

• The problem occurs during late night/early morning or late afternoon.
• The crash is likely to be serious.
• The crash involves a single vehicle on the roadway.
• The crash occurs on a high-speed road.
• The driver does not attempt to avoid the crash.
• The driver is alone in the vehicle.

Although evidence is limited or inferential, certain chronic, predisposing factors and acute situational factors are recognized as increasing the risk of drowsy driving and related crashes. These factors include:

• Sleep loss.
• Driving patterns, including driving between midnight and 6 a.m.
• Driving a substantial number of miles each year and/or a substantial number of hours each day.
• Driving in the late afternoon hours and driving for longer times without taking a break.
• Use of sedating medications, especially prescribed anxiolytic, tricyclic antidepressants and some antihistamines.
• Consumption of alcohol, which interacts with and adds to drowsiness.

Helpful behaviors include:

• Plan to get sufficient sleep.
• Do not drink even small amounts of alcohol when sleepy.
• Limit driving between midnight and 6 a.m.
• As soon as you become sleepy, stop.
• Take a short nap (15 to 20 minutes)
• Let a passenger drive.¹