The Department of Homeland Security recently announced changes in its approach to passenger screenings at airports, in an effort to increase security after the failed bomb plot on Christmas Day. However, statistically, it is more likely that a terrorist would target a subway system or public buses than an airplane. And a week after two coordinated bombings on the Moscow subway, many cities are concerned about securing their surface-level public transportation systems.

To talk about the threat facing ground transit systems, we speak to Brian Michael Jenkins, the director of the Mineta Transportation Institute’s Transportation Security Center. We also talk with Paul Browne, the Deputy Commissioner of Public Information for the New York City Police Department.

Brian Michael Jenkins says the chances of being the victim of a terrorist attack are still slim and Americans should not be fearful about using their public transit systems.