MINNEAPOLIS, MN --- Eight years after the September 11 attacks, researchers are still learning how those terrible events affected us. A number of studies have shown that people who lived closest to the sites of the terrorist attacks experienced heightened levels of stress and anxiety in the months following the attacks. Research has also indicated that elevated levels of stress can greatly impact day-to-day behaviors such as driving. 

Psychologist Alexander J. Rothman and his colleagues at the University of Minnesota analyzed records obtained from the U.S. Department of Transportation to see if there was any relation between geographic location and the rate of fatal traffic accidents that occurred in the three months immediately following the September 11 terrorist attacks.

Statistical analysis of the data yielded a number of interesting findings, which are reported in Psychological Science, a journal of the Association for Psychological Science. 

The authors found that there was an increase in the rate of traffic fatalities in the three months following the 9/11 attacks, but only in the Northeast, the region closest to the terrorist attacks on the World Trade Center. A follow-up analysis showed that there was a significant increase in the rate of traffic fatalities in the months following September 11 in the state of New York. This pattern of findings is consistent with the premise that stress-related reductions in the quality of driving led to a spike in the rate of fatal traffic accidents. 

In addition, the authors analyzed the traffic records to see if there was an increase in the rate of fatal traffic accidents involving drugs or alcohol. Compared to the same time period in the previous year, there was a 100 percentage point increase in the rate of drug- and alcohol-related fatal traffic accidents in the Northeast. 

The findings suggest that being close to the location of a traumatic event, such as the 9/11 attacks, may increase psychological stress, which may, in turn, impair one's driving ability and thus lead to an increase in fatal traffic accidents.

The authors noted that in this study, they "demonstrated the importance of considering various potential causes of behavioral changes after terrorist events occur." They concluded that "in general, thinking more theoretically about factors that shape people's responses to stressful events should help researchers anticipate behavioral reactions to terrorism."