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Flying still safer than driving, even in wake of Sept. 11

For any distance long enough that flying is an option, traveling on major airlines is far less dangerous than driving on even the safest available roads, an analysis by U-M Transportation Research Institute (UMTRI) researchers shows.

The conclusion holds true even when the latest statistics—including the deaths of passengers on the four planes hijacked on Sept. 11, 2001—are taken into account, Michael Sivak and Michael Flannagan write in the January-February issue of American Scientist magazine.

The researchers published a similar analysis in 1991, which documented a substantially lower risk of flying compared with driving in the United States. But in light of the Sept. 11 hijackings and continued threats of terrorist attacks, many Americans have become skittish about flying, so Sivak and Flannagan decided to recalculate the risks.

In their analysis, the researchers considered scheduled domestic passenger operations of 10 major U.S. airlines and travel by cars, light trucks, vans and sport utility vehicles on rural interstate highways—the main type of roadway that would be used as an alternative to flying and a type of road that is particularly safe per distance traveled.

Their calculations showed that driving the length of a typical nonstop flight—1,157 km or 719 miles—is 65 times as risky as flying. In fact, "for this type of flying to become as risky as driving, disastrous airline incidents on the scale of those of Sept. 11 would have to occur about once a month," says Sivak, head of UMTRI's Human Factors Division.

"We don't mean to sound melodramatic," says Flannagan, a senior associate research scientist at UMTRI, "but we want to convey the significance of that number. What's probably most important to note is how dangerous driving is. More than 42,000 lives are lost in road traffic accidents in the United States every year. That's an amazing number of deaths, especially considering that many of these are healthy, young people who otherwise would have had long life expectancies."

The researchers also note that most of the Sept.11 fatalities were not passengers in the four planes, but people in targeted buildings and on the ground. "We don't want to minimize the tragedy of Sept. 11," Flannagan says. "We're just making the point that from the perspective of personal safety, domestic flying on major airlines is still far safer than driving. There's a disconnection between the popular perception of risk and what the data really indicate. We're trying to contribute at a rational level to this issue that people are chewing over on a psychological level."

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