Drowsy driving

By: Drivers.com staff

Date: Wednesday, 01. April 2009

At some time or another, nearly every driver has the experience of almost falling asleep at the wheel. Yet it's difficult to combat this highly dangerous problem, partly because of drivers' resistance and partly because there is no available test to quantify the level of sleepiness when crashes do occur.

One effort to come to grips with the dangers of drowsy driving is a March 1999 report to the U.S. Congress about a joint collaboration between the National Highway Traffic Safety Administration (NHTSA) and the National Center on Sleep Disorders Research (NCSDR).

Although no driver is immune, says the report, three broad population groups are at highest risk, based on evidence from crash reports and on drivers' own descriptions of their sleep behavior and driving performance. These groups are: younger people (ages 16 to 29), especially males; shift workers whose sleep is disrupted by working at night or working long or irregular hours; and people with untreated sleep apnea syndrome (SAS) and narcolepsy.

The report says that 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 usually involves a single vehicle leaving a high-speed road
• the driver makes no attempt to avoid the crash and is usually alone in the vehicle.

Among the risk factors are a person's driving patterns, which may include driving between midnight and 6 a.m., driving a substantial number of miles each year and a substantial number of hours each day; driving in the late afternoon hours (especially for older persons); and driving for long periods without taking a break.

Adding to the risk is the use of sedating medications, especially prescribed anxiolytic hypnotics, tricyclic antidepressants, and some antihistamines, also the consumption of alcohol.

"The public needs to be informed of the benefits of specific behaviors that help avoid becoming drowsy while driving," the report adds.

Helpful behaviors include planning to get sufficient sleep, not drinking even small amounts of alcohol when sleepy, and limiting driving between midnight and 6 a.m.

"As soon as a driver becomes sleepy, the key behavioral step is to stop driving-for example, letting a passenger drive or stopping to sleep before continuing a trip" the report says. "Two remedial actions can make a short-term difference in driving alertness: taking a short nap (about 15 to 20 minutes) and consuming caffeine equivalent to two cups of coffee. The effectiveness of any other steps to improve alertness when sleepy, such as opening a window or listening to the radio, has not been demonstrated.

"A more informed medical community could help reduce drowsy driving by talking to patients about the need for adequate sleep, an important behavior for good health as well as drowsy-driving prevention." The detection and management of illnesses that can cause sleepiness, such as SAS and narcolepsy, are other health care-related countermeasures.

The report adds that information could be provided to the public and policymakers about the purpose and meaning of shoulder rumble strips, which alarm or awaken sleepy drivers whose vehicles are going off the road. These rumble strips placed on high-speed, controlled-access, rural roads reduce drive-off-the-road crashes by 30 to 50 per cent. However, rumble strips are not a long-term solution for sleepy drivers: any wake-up alert is an indication of impairment-a signal to stop driving and get adequate sleep before driving again.

"Employers, unions, and shift work employees need to be informed about effective measures they can take to reduce sleepiness resulting from shift work schedules. Countermeasures include following effective strategies for scheduling shift changes and, when shift work precludes normal nighttime sleep, planning a time and an environment to obtain sufficient restorative sleep."

To assist the educational campaign in developing its educational initiatives, the report recommends addressing three priority areas:

1. Educate young males (ages 16 to 24) about drowsy driving and how to reduce lifestyle-related risks.
2. Promote shoulder rumble strips as an effective countermeasure for drowsy driving.
3. Educate shift workers about the risks of drowsy driving and how to reduce such risks.

A follow-up project by Harvard School of Public Health resulted in a series of focus groups to explore the educational needs and motivations of the two potential target populations recommended by the expert panel: young males and shift workers.

The young men had a variety of levels of education and types of employment, but were nearly unified in their attitudes about sleep and drowsy driving. They reported sleeping between five and seven hours a night and were aware that drowsiness was a hazard when driving. However, they seemed to accept these risks as part of their lifestyle, and appeared to be unwilling to change either their sleep routines or their driving behavior.

Shift workers reported getting less sleep than the young men (four to six hours per 24-hour period) with sleep being fragmented into two or more occasions. Shift workers were acutely aware of the risks of driving when sleepy, many of them having had personal experiences with falling asleep when driving home and not remembering substantial parts of the trip.

In contrast to the young males, however, the shift workers seemed eager to learn how to improve their sleep and appeared to be motivated to change their routines if they could be more rested as a result. However, many expressed frustration with factors "beyond their control" that interfered with their getting adequate and restful sleep.

To see more drowsy driving information, visit the NHTSA's drowsy driving program, or see the Drivers.com section on Fatigue.

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