Fighting fatigue: to improve the safety of the transportation system, multimodal partnerships within USDOT are addressing problems caused by sleep deprivation

Public Roads, Sept-Oct, 2003 by John Sullivan, J., IV

One person's lack of sleep Call contribute to another's lack of safety on the Nation's roads. According to the National Highway Traffic Safety Administration's (NHTSA) Senior Research Psychologist Jesse Blatt, fatigue and sleep deprivation contribute to about 100,000 police-reported highway crashes, causing more than 1,500 deaths annually in the United States. And the National Transportation Safety Board also has linked operator fatigue with a number of costly public incidents, including the Exxon Valdez grounding and the collision of subway trains on the Williamsburg Bridge in New York City.

Sleep deprivation and operator fatigue are critical safety issues that cut acres all modes in the transportation industry. Fatigue affects physical and mental alertness, decreasing an individual's ability to operate a vehicle safely and increasing the risk of human error that could lead to fatalities and injuries. As with drugs and alcohol, sleepiness slows reaction time, decreases awareness, and impairs judgment. Long hours at the wheel make truck drivers particularly prone to drowsy-driving crashes, but fatigue and sleep deprivation also affect other transportation operators such as railroad engineers, airline pilots, and ship captains.

"The incidence of fatigue is underestimated in virtually every transportation mode because it is so hard to quantify and measure," says Dr. Steve Popkin, leader of the Fatigue Monitoring and Countermeasures Research Team at Volpe National Transportation Systems Center in Cambridge, MA.

"Data on fatigue-related crashes is hard to come by," he adds, "because it is difficult to determine the degree to which fatigue plays a role in crashes. For example, if a motorist is unharmed in a crash, the increased arousal following the incident usually masks the impairment that could assist investigating officers in attributing the crash to sleepiness."

The modal administrations within the U.S. Department of Transportation (USDOT) are collaborating through partnerships, research and development, education and awareness campaigns, and policy changes to address fatigue-related crashes. In addition, the Federal Motor Carrier Safety Administration (FMCSA) and the Federal Railroad Administration (FRA) are partnering with an Australian researcher to explore how strategies from "down under" might prove valuable in the United States.

Fatigue and Highways

Sleepiness impairs driving performance, affecting reaction time, vigilance, attention, and information processing. In a poll conducted by the National Sleep Foundation in 1999, 62 percent of adult survey respondents reported driving a car or other vehicle while feeling drowsy in the previous year. Twenty-seven percent reported that they had dozed off while driving. Twenty-three percent stated that they knew someone who experienced a fall-asleep crash within the past year.

In 1998, the National Heart, Lung, and Blood Institute, the National Center oil Sleep Disorders Research, and NHTSA published a report on drowsy driving. According to the report, Drowsy Driving and Automobile Crashes: Report and Recommendations, the typical sleep-related crash has the following characteristics: The crash occurs during late night, early morning, or mid-afternoon on a high-speed road; a single vehicle leaves the roadway; and the driver is alone in the vehicle and does not attempt to avoid die incident. Most at risk for sleep-related crashes are young people (ages 16 to 29, especially" males) who tend to stay tip late, sleep too little, and drive at night. Truck drivers, shift workers, frequent travelers, individuals using sedatives, and people with undiagnosed or untreated sleep disorders also are at risk.

Unlike the situation with alcohol-related crashes, investigators do not have measurable tests (blood or breath) to help them quantify levels of sleepiness. Also, because sleep deprivation increases the likelihood of attention lapses, drowsiness or fatigue may play a role in crashes attributed to other causes as well.

"When we're tired," says Popkin, "our ability to think and react swiftly is diminished. To compensate, we limit the amount of information we use for driving, for example, fixating on the road ahead instead of using the mirrors or glancing at the dashboard or traffic controls. An investigator may report that the driver ran a red light causing a crash, but in reality it happened because the driver wasn't appropriately vigilant due to his state of sleepiness and fatigue. We are working to come up with a way to determine the fatigue component, but we're not nearly there yet."

Installing shoulder and centerline rumble strips is one engineering method that the Federal Highway Administration (FHWA) supports and State departments of transportation use to reduce the likelihood of crashes. The combination of jarring motion and loud noise alerts drivers when they cross over a rumble strip, helping prevent drift-off-road crashes. (See "Rumbling Toward Safety," page 28.) In fact, according to NHTSA's Drowsy Driving report, rumble strips placed on high-speed, controlled-access rural roads can reduce run-off-the-road crashes by 30 to 50 percent.