Carnegie Mellon University

Recalled Toyotas

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What's the Real Risk?

Driving Toyota

Toyota has recently made headlines due to a problem with the accelerator sticking on certain vehicles. Nineteen fatalities have been linked to the issue, and Toyota has recalled 2.3 million cars in the U.S. for repairs, which has caused a sense of panic for recalled car owners and the general public.

To put things in perspective, Carnegie Mellon University Professor Paul Fischbeck, a risk expert, calculated the risk of driving a recalled Toyota and found that the accelerator problem increases the driving risk by only 2 percent.
      
"There hasn't been a discussion about the actual risk of driving one of Toyota's recalled vehicles," said Fischbeck, a professor of social and decision sciences and engineering and public policy. "Even the messages from the Transportation Secretary have been confusing. First, it's a recommendation not to drive the cars in question at all. Then, that was retracted. I think it's important for people to realize that when you look at the actual risk of driving one of these cars, it's actually very low."
      
Consumers also may want to reconsider parking their recalled Toyotas until repairs have been made. "Replacing driving by walking really increases the risk of dying," Fischbeck said. "Walking a mile is 19 times or 1,900 percent more dangerous than driving a mile in a recalled Toyota. Driving while using a cell phone would increase risk much more than the chance of having a stuck accelerator."
      
In the U.S., there is a little more than one fatality for every 100 million miles driven. The average U.S. vehicle logs about 13,000 miles each year. Based on these averages, for the 2.3 million Toyotas being recalled, there are about 340 fatalities every year for causes unrelated to the accelerator. The accelerator problem is adding about six deaths every year to this total — meaning that the accelerator problem is increasing the driving risk by about 2 percent.  
      
The relative increase in driving risk depends on the individual driver. For a 35-year old woman (some of the safest drivers on the road), driving risk is very low (less than half the national average), so the additional risk from stuck accelerators would increase their driving risk by 3.5 percent. For a teenage male driver whose risk is 3.5 times greater than the national average, the driving risk only increases 0.5 percent because of the problem.
      
If every vehicle on the road in the U.S. had this problem, there would be an additional 600 deaths every year. Driving a recalled Toyota for about a half mile less per day would be the same as if you drove in a vehicle without the problem.  
      
Thinking about risks in terms of gambling, the chance of dying in a year because of the accelerator problem is about two in a million. This is the same as flipping 19 coins one time each and getting 19 heads.
      
Of course, people die from many things other than automobile crashes. The additional risk from the accelerator problem increases an individual's annual risk of dying by less than 0.5 percent. And because the risk of dying in a given year increases with age, for retirees the additional risk is less than 0.01 percent.
      
"Bottom line, it is important to keep risks in perspective," Fischbeck said. "The stuck accelerator problem does make driving riskier and needs to be fixed. But at the same time, the increased risk is very small."

Related Links: Social & Decision Sciences  |  Engineering & Public Policy