What is the best way of dealing with drowsy driving?
Posted November 13, 2008
Quiz with bonus essay:
Of the following situations, which poses the greatest danger for a motor vehicle accident (MVA)? Bonus essay: Explain your answer.
A. A 35 year old, 180 lb, man consumes six beers over four hours at a party and drives home.
B. A 27 year old medical intern drives home after working a 36 hour shift in which she got no sleep.
C. Both A and B are equally dangerous.
D. Neither A nor B poses any increased danger of a MVA.
As it turns out the answer is most likely: B.
For a rough estimate, a 180 lb man consuming six beers over a four hour period would have a blood alcohol concentration (BAC) of approximately 0.07%, below the legal limit of 0.08% for driving while intoxicated in the United States. This is not to say it would be safe to drive with this level of alcohol as it would result in impairment of cognitive functioning and most definitely is not advised. (Please note that there are a number of BAC calculators on the internet which take into consideration different factors such as weight and sex that may affect BAC and often given different results for apparently similar input data. While they may give some useful idea about the impact of a given amount of alcohol consumed they are inexact and the best advice is: Do Not Drink and Drive. Period.)
Somewhat surprisingly, however, a number of studies have shown that the loss of more than 24 consecutive hours of sleep (not uncommon in certain work situations where people have, for example, overnight shifts) can result in a level of cognitive impairment in judgment and reaction time equal to a 0.1% BAC, well above the legal limit. Each day many health care professionals drive home after a night of conducting sleep studies or working in an emergency room and may have gone this long without sleep. Even more frightening is the possibility of a chronically sleep deprived individual drinking and then driving so that overall impairment is even greater.
Sleep deprivation results in impairment of cognitive ability and causes significant risk of making mistakes when driving or engaging in potentially dangerous activity. For example, several major industrial accidents in the recent past were associated with sleep deprived workers including the Three Mile Island nuclear power plant accident, the Chernobyl nuclear catastrophe, the Exxon Valdez oil spill, and the Challenger space shuttle disaster.
Drowsy driving is not a small problem. Nearly 1% of the driving population admits to having had a drowsy driving related MVA and over 50% of drivers admit to having driven at some point while drowsy. The National Highway Traffic Safety Administration has estimated that every year there are approximately 100,000 MVAs related to drowsy driving with 76,000 injuries and 1500 deaths as a result.
When considering the number of truck drivers, police officers, health care providers, military personnel, astronauts and other professionals potentially working under conditions of significant sleep deprivation it is clear that there is a considerable risk of serious accidents and deaths because of lack of sleep. You do not want your pilot to be falling asleep as you are landing at a busy airport.
Many people suffer from undiagnosed sleep disorders such as obstructive sleep apnea that can cause daytime drowsiness. There are millions of commercial drivers in the United States and many of them may be driving without adequate sleep or may have sleep disorders that can impair their ability to drive. You do not want your child's bus driver falling asleep while driving the bus because she does not know that she has sleep apnea with daytime drowsiness and is having "microsleeps" without her knowledge. A bus can cover a great deal of distance during a 3 to 10 second microsleep.
There are a number of ways in which anyone can become sleep deprived. Sleep deprivation may be acute, for example, getting no sleep in the previous 24 hours or chronic as when someone regularly gets less than an adequate amount of sleep. After 16 hours of continuous wakefulness performance begins to decline. If adults get less than 5 hours of sleep per night the drive to sleep greatly increases and cognitive functioning declines. An individual with a BAC of 0.07% will have impaired judgment, reasoning ability and memory. He or she will be unable to accurately judge the state of intoxication so as to make an appropriate judgment about the ability to drive. As noted above, a person who has 24 hours of sleep deprivation can have the same level of impaired judgment and delayed reaction time as a person with a BAC of 0.1%.
A significant debate in the sleep medicine field relates to what the appropriate approach should be to this public health problem. One approach is to outlaw driving while sleepy and treat it as a criminal offense in the same way as driving while intoxicated. This has been tried in one state with limited results. Other options involve the use of education, screening (e.g. for sleep apnea in truck drivers) and technology to help alert drivers to the fact that they are too impaired to drive. For example, the relatively "low tech" method of providing rumble strips on highways has already shown evidence of effectively reducing the frequency of drowsy driving accidents. More complex technology may be useful in the future such as measuring brain waves or eyes movements for evidence of drowsiness. The question arises: Would people want such relatively invasive technology incorporated into their cars?
To date New Jersey is the only state to outlaw a specific type of driving while sleepy. This is known as Maggie's law and was enacted following an incident on July 27, 1997 when Maggie McDonnell, a college student, was killed in an automobile accident when struck by a van driven by someone who had not slept in 30 hours and had also smoked crack cocaine. The van driver fell asleep at the wheel at the time of the accident. This led to 2 trials and resulted in the driver of the van being given a $200 fine and a suspended jail sentence as driver fatigue could not be considered as a factor by the juries.
Maggie's mother, Carole McDonnell, could not believe that this degree of irresponsible behavior had led to such a minimal punishment. She campaigned to pass a law to help prevent motor vehicle accidents due to drowsy driving. Maggie's law was eventually passed in 2003 and allows for a significant prison sentence for driving while fatigued which is defined as being without sleep for more than 24 consecutive hours prior to the accident. Of note, in the first two years after its passage only one person was prosecuted for driving while fatigued. This did result in a conviction in 2004 for vehicular homicide with a five year prison sentence. Several other states have considered similar laws but enforcement is difficult as there is no current test to prove conclusively that someone is sleep deprived. This is unlike the situation with alcohol where accurate measures of BAC do exist and are readily available.
A number of difficult questions are raised by efforts to pass laws such as Maggie's law. If such laws are passed around the country would they help and how would they be enforced? Should someone with undiagnosed sleep apnea resulting in unrecognized drowsy driving be treated in the same way as someone who knowingly drove after a prolonged time without sleep? Is 24 hours without sleep an adequate measure of when someone is too fatigued to drive? Should hospitals provide time and space for health care professionals to nap before driving home after all night shifts? And so on.
This obviously is a complex issue and one that presents significant challenges to finding a workable solution. What do you think? Should we as a nation specifically make drowsy driving illegal with serious penalties on the same order as driving while intoxicated or is it better to use other approaches such as better education, more police training and innovative technology to prevent drowsy driving? Let me know.