The Jones family feels lucky to be living in Alexandria, VA, close enough to commute to the nation's capital but removed enough to feel "residential." Washington DC's reputation for horrendous traffic is well-founded but the Jones family has its commuter routine down for a seamless morning kickoff. Mr. Jones enjoys his daily walk to the local bus, which drops him at the metro stop where he hops the commuter rail to his office in DC. Mrs. Jones takes the same route into the DC Amtrak station, where she takes the "heavy rail" to her office in Baltimore. Commuter rail passes are subsidized by employer sponsored programs and are a standard component of the family budget. The Jones family also uses the MARC train to visit family who live in Northern Maryland. Mass transit is often a wise economical alternative to the family gas-guzzling SUV, particularly on the terminally congested DC beltway. Unfortunately, the very regularity and convenience which makes mass transit such a mundanely fundamental part of our everyday lives also makes it an attractive "soft target" for terrorist attack, as has been repeatedly demonstrated overseas. Explosive attacks on buses in Israel occur with historical and horrifying frequency. 1995 brought the world's first major chemical terror attack on the Tokyo subway system and repeated terrorist attacks on Paris' commuter rail system. The Madrid railway attacks of 2004 and the infamous "7/7" attacks on London's subway and bus systems provide other examples of the potential devastation within mass transit's densely packed and extremely busy confined spaces. As traditional targets become more "hardened" by enhanced security measures and funding for protective initiatives, terrorist tactics have morphed to address these soft targets - notably mass transit.  Read the monograph.