Closed circuit television video (CCTV) surveillance systems need to be introduced or enhanced in the public areas within United States’ mass transit systems. London’s extensive system was used very successfully in the investigation of the July 2005 terrorist attacks on its subway and bus systems. That effective investigatory use of CCTV is very likely to be a significant deterrence to future terrorist activities on London mass transit. The United States must be prepared in the event of similar attacks on its soil. As roughly twenty times more people travel by mass transit than by air, it is time for this nation’s transportation security focus to shift to mass transit, and to use CCTV widely in public mass transit systems.