K. Jack Riley writes in his paper "Flight of Fancy? Air Passenger Security Since 9/11"
Researchers have estimated that the 9/11 attacks generated nearly 2,200 additional road traffic deaths in the United States through mid-2003 from a relative increase in driving and reduction in flying resulting from fear of additional terrorist attacks and associated reductions in the convenience of flying. If the new security measures are generating similar, or even smaller, substitutions and the driving risk has grown as hypothesized, the new methods could be contributing to more deaths annually on U.S. roads than have been experienced cumulatively since 9/11 from terrorism against air transportation targets around the world.
Happy driving, everybody!
Riley's paper appears as Chapter 12 of The Long Shadow of 9/11: America's Response to Terrorism, edited by Brian Michael Jenkins and John Paul Godges. It was recommended in Timothy Taylor's "Recommendations for Further Reading" in Journal of Economic Perspectives, Vol. 25, No. 4 (Fall 2011), which was blogged about by Scott Sumner here. One of Sumner's commenters claims TSA is not designed to prevent lives, but to protect the macro economy. If this is true, the TSA is a massive tax of the "corporate welfare" variety that gets the 99% all hot in the pants. My privacy is invaded and my body is given cancer so corporations can operate in a slightly-less-risky environment. Why are there no unwashed hippies occupying airport screening lines?