Edit: I found a paper from 2007 that claims there were 129 extra driving fatalities in the last quarter of 2002 due to harsher airport security. http://aem.cornell.edu/faculty_sites/gb78/wp/JLE_6301.pdf (page 27)
Or that backscatter X-ray machines odds of giving you cancer are roughly equal to those of dying in a terrorist attack: http://cosmiclog.msnbc.msn.com/_news/2010/11/16/5477568-are-...
Edit: I found a paper from 2007 that claims there were 129 extra driving fatalities in the last quarter of 2002 due to harsher airport security. http://aem.cornell.edu/faculty_sites/gb78/wp/JLE_6301.pdf (page 27)