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Most Auto Accidents Caused By Drivers, Not Defects

Cell phone use while driving is one distraction that can contribute to driver-induced accidents. Research shows that drivers are at least partly to blame for accidents about 90 percent of the time and wholly to blame more than half the time. Robert F. Bukaty/AP hide caption

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Robert F. Bukaty/AP

Cell phone use while driving is one distraction that can contribute to driver-induced accidents. Research shows that drivers are at least partly to blame for accidents about 90 percent of the time and wholly to blame more than half the time.

Robert F. Bukaty/AP

Driving a Toyota may feel pretty risky these days, given all the scary stories about sudden acceleration, failing brakes and recalled vehicles. But that feeling has a lot more to do with emotion than statistics, experts say. That's because defective vehicles are almost never the cause of serious crashes.

"The whole history of U.S. traffic safety in the U.S. has been one focusing on the vehicle, one of the least important factors," says Leonard Evans, a physicist who worked for General Motors for three decades and wrote the book Traffic Safety.

To Err Is Human

Studies show that the vehicle itself is the sole cause of an accident only about 2 percent of the time. Drivers, on the other hand, are wholly to blame more than half the time and partly to blame more 90 percent of the time.

A look at data on Toyotas from the National Highway Traffic Safety Administration confirms this pattern. The data show that in the decade ending in 2008, about 22,000 people were killed in vehicles made by Toyota or Lexus, Evans says. "All these people were killed because of factors that had absolutely nothing to do with any vehicle defect," he says.

During that same period it's possible, though not yet certain, that accelerator problems in Toyotas played a role in an additional 19 deaths, or about two each year, Evans says. And even if an accelerator does stick, drivers should be able to prevent most crashes by simply stepping on the brakes, Evans says. "The weakest brakes are stronger than the strongest engine," he says.

'More Frightened Than We Need To Be'

Given all we know about the potential risks from Toyotas, we're far more frightened than we need to be, Evans says. But that's not surprising, says David Ropeik, a risk communication consultant in Massachusetts and the author of the book Risk.

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"We don't calculate risk based on our probabilistic chances of something bad happening," Ropeik says. "Instead, much of our perception of risk comes down to how much we trust a person or company making a particular product." And Toyota has lost people's trust, in part because media reports have suggested the company was not upfront about known problems with some of its vehicles, he says.

People also tend to think something is especially dangerous if it's being imposed on them, Ropeik says. "Imposed risk always feels much worse than the same risk if you choose to do it yourself," he says. "Like if you get into one of these Toyotas and they work fine but you drive 90 miles an hour after taking three drinks. That won't feel as scary even though it's much riskier."

You might think people who drive cars that haven't been recalled, or weren't made by Toyota, would feel safer. "But that's not how our minds work," Ropeik says. Instead, bad news about one car maker's product is likely to shake confidence in all cars, he says.

Something similar happened a few years ago with a medical device, Ropeik notes. The news media began reporting that one company was having problems with its implantable defibrillators and seemed to be trying to hide those problems. "When that hit the news, people with defibrillators from all major manufacturers rushed to the hospital to have them all taken out of their hearts," Ropeik says. So Toyota's problems are likely to shake people's confidence in all cars, he says.

Of course, if people's fear of getting in their cars causes them to avoid driving, they really will be less likely to have an accident.