Garrick Blalock, Vrinda Kadiyali and Daniel H. Simon, writing in the journal Applied Economics (June 2009 – Volume 41, issue 14, pg. 1717) came to a fascinating conclusion. After the highly dramatic 9/11 attacks, many travelers elected to go by automobile, in preference to taking airplanes (as the airlines know all too well – their business really suffered after 9/11). One little-known aspect of these decisions, however, is that by going on the road instead of by air, passengers expose themselves to far greater risk. Indeed, in the US, close to 40,000 fatalities occur each year (according to the Fatality Analysis Reporting System. The number of airplane related fatalities worldwide, in contrast is less than a thousand deaths, according to recent reports. The disparity in how dangerous the two modes of transportation are prompted the researchers to ask whether a side effect of the terrorism attacks (fear of flying) increased the risk exposure of people who chose to drive, rather than fly.
They controlled for time trends, weather, road conditions and other factors and found that 327 additional driving deaths per month in late 2001 could be attributed to a shift in preference away from airplanes and toward road transportation. While the effect weakened over time, the authors speculate that a smany as 2,300 driving deaths may be attributable to the attacks.