Good evening. Thank you for inviting me here today to talk to you about the role of driver fatigue in traffic accidents. This is an important topic, one that has long occupied the interest of the Safety Board, and I commend you for convening this symposium to confront the issue and develop new and practical counter-measures to reduce fatigue-related losses.
For many years, the Safety Board has been concerned about the effects of fatigue in all modes of transportation and has addressed this problem through accident investigations, safety studies, and recommendations. In 1995, we co-sponsored with the National Aeronautics and Space Administration a symposium on fatigue countermeasures.
As you may already know, the National Transportation Safety Board is an independent federal agency with two major tasks: to determine the probable causes of major transportation accidents and to issue safety recommendations aimed at preventing accidents. We do this by investigating accidents and by conducting safety studies. We are the eyes and ears of the American people at an accident site.
The Safety Board investigates accidents in all 5 modes of transportation: aviation, railroad, marine, pipeline and highway. In too many of these investigations, we have found fatigue to have contributed to the causes of accidents.
I know that many of you attending this conference are from Alaska and are familiar with the grounding of the U.S. Tankship EXXON VALDEZ in Prince William Sound, near Valdez, Alaska on March 2, 1989. Although there were no human injuries, about 258,000 barrels of cargo were spilled when eight cargo tanks ruptured, resulting in catastrophic damage to the environment and losses to the local wildlife. While damage to the vessel and cargo amounted to more than $28 million, the cost of the cleanup of the spilled oil during 1989 alone was almost $2 billion, probably the most expensive fatigue-related accident in history.
As with most accidents, we found that this catastrophic oil spill resulted from a cascade of errors and circumstances. The probable cause of the grounding of the EXXON VALDEZ was:
- the failure of the third mate to properly maneuver the vessel because of fatigue and excessive workload;
- the failure of the master to provide a proper navigation watch because of impairment from alcohol;
- the failure of Exxon Shipping Company to provide a fit master and a rested and sufficient crew for the EXXON VALDEZ;
- the lack of an effective Vessel Traffic Service because of inadequate equipment and manning levels, inadequate personnel training, and deficient management oversight; and
- a lack of pilotage services.
More recently, the Safety Board investigated a highway accident involving the collision of a propane truck with a bridge column in White Plains, New York. About 12:30 a.m., on July 27, 1994, a tractor cargo-tank semitrailer loaded with 9,200 gallons of propane was traveling east on Interstate 287. As the truck drifted across the left lane onto the left shoulder and struck the guardrail, the tank hit an overpass column. The tractor and semitrailer separated, and the front head of the tank fractured, releasing propane that vaporized into gas. The resulting vapor cloud expanded until if found a source of ignition. When it ignited, according to an eyewitness, a fireball rose 200 or 300 feet in the air. The tank was propelled northward about 300 feet and landed on a frame house, engulfing it in flames.
The truck driver was killed, 23 others were injured, and an area with a radius of approximately 400 feet was engulfed by fire.
We found this to be an example of a classic fatigue accident. The Board found the probable causes to be the reduction in alertness of the driver, consistent with falling asleep, caused by his failure to properly schedule and obtain rest, and the failure of the company to exercise adequate oversight of the driver's hours of service.
These two accidents, which are only two of the many accidents in which fatigue has been a factor, illustrate the tragic results of operating while fatigued. Each of us here knows exactly how it feels to be fatigued and what is does to us. We've all experienced the dramatic effects of extreme fatigue when we've tried to drive an hour longer than we should or even tried to stay up to watch a movie.
With the growth of our 24-hour society, people are exposed more and more to the dangers of fatigue. Today, we need only drive from our home, live near railroad tracks, or board an airplane to face first-hand the potential dangers from operator fatigue. Our society now demands that goods be shipped anywhere in the country - or even around the world - overnight. Many factories have adopted just-in-time materials delivery. Trucking deregulation might have been a boon to businesses and consumers by resulting in lower costs of goods and services, but it didn't alleviate the problem of fatigue for truck drivers. On the contrary, it might have added to the pressures that lead to fatigue.
In general, fatigue leads to diminished performance in many ways:
- As fatigue increases, performance becomes more variable, making performance less reliable.
- Speed of physical reaction time and speed of thought processes are slowed.
- There is a tendency to make mental errors and flawed judgments.
- False responding, or responding when a stimulus isn't present, also increases.
- Memory errors are more likely to occur.
- Finally, vigilance decreases, and motivation is reduced.
The Safety Board has issued about 80 fatigue-related safety recommendations since 1972 to the modal administrations in the Department of Transportation, transportation operators, associations and unions. In 1989, we issued three major safety recommendations to DOT, asking the Secretary to expedite a coordinated research program on the effects of fatigue on all modes of transportation, to develop an educational program and to review hours of service regulations. This is on our list of Most Wanted Safety Recommendations.
The fact of the matter is that while highway crashes cost society over $150 billion a year, no one knows how much of this is attributable to fatigue. But a study of ours indicates that fatigue represents a substantial portion of it.
In 1990, the Safety Board conducted a study of 182 accidents that were fatal to the truck driver. Although the study's main purpose was to assess the role of alcohol and drug use in those accidents, we found that the most frequently cited probable cause was fatigue. We followed up with a second study that examined the factors that promote fatigue.
We used our standard investigative and probable cause determination procedures for investigating 107 single vehicle, heavy truck accidents. In all of these accidents, the driver survived and was able to be interviewed soon after by one of the Board's investigators. The Board carefully examined the truck drivers' duty and sleep patterns for 96 hours before the accident and the regularity or irregularity of their sleep patterns.
We found that the most critical factors in predicting fatigue-related accidents are the duration of the most recent sleep period, the amount of sleep in the past 24 hours, and whether the sleep was continuous or split. As a result of the findings, we recommended a revision of the hours-of-service regulations to give drivers the opportunity to get at least 8 continuous hours of sleep.
In our study, truck drivers in fatigue related accidents had an average of 5 1/2 hours of sleep in the last sleep period prior to the accident. This is about an hour and a half less than what the drivers felt they needed to feel rested. It is also 2 1/2 hours less than the eight hours obtained on average by truck drivers in our study in nonfatigue-related accidents. The findings further indicate that truck drivers involved in fatigue-related accidents obtained less than 7 hours of sleep in the 24-hour period before the accident, compared to more than 9 hours obtained by drivers not involved in fatigue-related accidents.
In drafting the hours-of-service regulations in 1937, the Interstate Commerce Commission wrote:
"It is obvious that a man cannot work efficiently or be a safe driver if he does not have an opportunity to secure 8 hours' sleep. Allowance must be made for eating, dressing, getting to and from work, and the enjoyment of the ordinary recreations."
Sixty years later, that is still our goal.
The Safety Board recognizes that regulations cannot assure adequate sleep. Nevertheless, regulations can and must provide the opportunity to obtain an adequate amount of rest. However, the 8-hour off-duty requirement in the current regulations doesn't do so because it doesn't provide time for eating, travel, personal hygiene, and recreation. And, depending on various factors, including the time of day, a driver may not be able to fall asleep immediately at the beginning of his or her 8-hour off-duty period.
Our study also addressed split sleep patterns. Although the drivers were obtaining 8 hours of sleep, they were obtaining it in small blocks of time - an average of 4 hours at a time. Research shows that sleep accumulated in short time blocks impedes the recovery of performance abilities. The Safety Board recommended elimination of the exemption that allows for split sleep. We are not calling for elimination of sleeper berths. The point is that the sleeper berth exemption encourages less than 8 hours of continuous sleep.
Up to this point I have focused on commercial truck drivers, but they are not the only ones who are in danger of driving while drowsy. Each and every one of us poses a risk if we get behind the wheel of a vehicle while fatigued, or if we stay there until we become fatigued.
Data from the Fatal Accident Reporting System, which is a census of all fatal accidents on public roads, show that there were 1,440 accidents involving driver fatigue in 1994. Over 90% of these fatigue related accidents involved drivers of passenger cars or light trucks. For your information, just over 2% of the accidents occurred in the State of Washington.
However, these numbers probably underestimate the actual occurrence of fatigue in accidents. First of all, not all State police reports include a category of fatigue on their forms. Second, fatigue is difficult to determine; it is not like drug or alcohol testing where a blood test can be given to determine the presence of illegal substances. There is no such test for fatigue. Instead, determination of fatigue relies heavily upon tracing the operators' history to better understand the patterns of their duty and rest cycles, duration of sleep periods and other scheduling information.
I believe that most people have accepted the fact that driving while drowsy creates a danger on the roadways. There are, however, steps that can be taken to minimize the problem.
Earlier I mentioned that the Safety Board and NASA co-sponsored a multi-modal symposium on managing fatigue in transportation. The symposium was attended by nearly 600 people from 16 countries representing all modes of transportation. This event was unique because people from management, labor, academia, and government all worked and learned together. Renowned sleep and fatigue experts talked about the physiological basis for fatigue, sleep disorders, the effect of fatigue on performance and countermeasures to fatigue.
The bottom line is that there is no cure or quick fix to fatigue. The only way to counteract fatigue is to get enough sleep. Sleep loss is cumulative. If you need 8 hours sleep a night but only get 7, at the end of the week you have a sleep deficit of 7 hours. The only way to repay that debt and alleviate or avoid the fatigue associated with it is to sleep. Napping, particularly naps of about 40 minutes duration, have also been shown to be an effective way to promote alertness temporarily. It is important to realize that naps are not a substitute for a longer period of sleep but instead should be viewed as a supplemental sleep period in addition to a full night sleep.
Combating fatigue is a shared responsibility among government, industry, and employees. There is also a family responsibility; demands on a worker's time go well beyond time spent on the job. Families must make sure their needs do not deprive the workers of their much-needed sleep.
Much is known about fatigue, what causes it and what to do to prevent it. It is time to implement this knowledge to prevent fatigue related accidents from occurring.
This symposium is a great example of confronting this issue at the grass roots level. It will take the combined efforts of the federal government, State governments and private industry to eliminate operator fatigue as a major safety issue in all modes of transportation.
Thank you for inviting me, and for your continuing efforts to deal with fatigue in transportation and therefore save lives of our fellow citizens.
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