Most people are aware of the intrinsic dangers of drinking and driving but have not come to appreciate that drowsy driving can be just as fatal. Being awake for 18 hours is equal to a blood alcohol concentration (BAC) of .08 percent, which is the standard in many states to declare the drive legally drunk. To help convey to you the enormity of the problem let me cite you some statistics: 100,000 crashes each year are caused by fatigued drivers; 55 percent of drowsy driving crashes are caused by drivers less than 25 years old; according to the National Sleep Foundation's (NSF) Sleep in America poll, 60 percent of Americans have driven while feeling sleepy and 37 percent admit to actually having fallen asleep at the wheel in the past year. NSF's 2000 Sleep in America poll reported that when they are driving drowsy, 42 percent of those surveyed said they became stressed, 32 percent got impatient and 12 percent tended to drive faster.

Frighteningly, many drivers cannot tell if or when they are about to fall asleep. If sleepiness comes on while driving, the rationalizing self statement kicks in, "I can handle this, I'll be fine." Nonetheless, they are putting themselves and others in grave danger. Like alcohol, sleepiness slows reaction time, decreases awareness, impairs judgment and increases your risk of crash. Safe driving requires a person's complete attention and focus.

Let's define some terms so that we are sure we share a mutual understanding of what we are dealing with. Understanding the meaning of drowsy driving or driver fatigue relies upon on how the concept of "fatigue" is defined. Fatigue is a general term commonly used to describe the experience of being "sleepy," "tired," "drowsy," or "exhausted." While all of these terms have various meanings in research and in our own conceptualizations, they tend to be used interchangeably in the traffic safety and transportation fields.

There are many underlying causes of sleepiness, fatigue, and drowsy driving, including sleep loss from restriction or too little sleep, interruption or fragmented sleep; chronic sleep debt; circadian factors associated with driving patterns or work schedules; undiagnosed or untreated sleep disorders; time spent on a task; the use of sedating medications; and consumption of alcohol when already tired. These factors have cumulative effects and a combination of any of these can greatly increase one's risk for a fatigue-related crash.

Sleepiness or fatigue causes the following: impaired reaction time, judgment and vision; problems with information processing and short-term memory; decreased performance, vigilance and motivation; increased moodiness and aggressive behaviors.

In addition to the dangers of driving under the influence of fatigue, several states are considering legislation that would allow police officers to charge drowsy drivers with criminal negligence if they injure or kill someone while driving if they have not had adequate sleep. Clearly such legislation is in its early stages as the subjectivity and ambiguity inherent in such actions are obvious. For example, there is no test to determine sleepiness as there is for intoxication, i.e., a "breathalizer." There is little or no police training in identifying drowsiness as a crash factor and self-reporting is unreliable.

What are some of the warning signs that should tell a driver to stop and rest?: your eyelids droop and your head starts to nod; yawning becomes almost constant and your vision seems blurry; you blink hard; daydreaming, wandering/disconnected thoughts; trouble remembering the last few miles driven; missing exits or traffic signs; drifting from your lane; tail-gaiting, or hitting a shoulder rumble strip and feeling restless or irritable.

A final thought, that being while it is not universal as yet a NSF poll found 96 percent agreeing that information about driving while drowsy should be included in tests for a driver's license.