In the wake of two recent bomb plots targeting the D.C. Metro, authorities have announced they will begin conducting random inspections of carry-on items.

Using explosive screening chemicals and K-9 units, Metro Transit police will randomly select bags or packages to check for hazardous materials. The random searches, which will be conducted throughout the region's 86 rail stations and 12,000 bus stops "will increase visible methods of protecting our passengers and employees, while minimizing inconvenience to riders," MTPD Chief Michael A. Taborn explained.

Customers can refuse to enter a station if they don't want to be screened, and they can also refuse to have their packages searched. In either case, the passenger will not be allowed to bring those bags into the Metro system. Similar programs are already in place in New York and Boston, and have been upheld by federal judges as constitutional.

Each of these programs was put into place in recognition of the threat posed to the American rail and bus infrastructure. In October, authorities arrested Farooque Ahmed, a 34 year old Virginia man who plotted to bomb the DC Metro. On Monday, authorities arrested another Virginia man, Awais Younis, and charged him with threatening to bomb the D.C. subway system.

With reports that al Qaida is preparing a series of attacks on Western targets, especially in the United States, during the Christmas season, it's important to consider ways to protect these soft targets. The March 11, 2004 Madrid train bombings provide a sense of what a successful attack could look like, killing nearly 200 people and wounding almost 2,000. As Ray Locker, the IPT's Managing Director recently explained, "if you want to paralyze a city or kill a lot of people, a major public transportation system is where you would go."

Following the thwarted attack earlier this year by Ahmed, the head of TSA John Pistole raised the issue of increased security to trains and busses during a press conference. "Given the threats on subways and rails over the last six years, going on seven years, we know that some terrorist groups see rail and subways as being more vulnerable because there's not the type of security that you find in aviation."

Metro announced similar plans for random searches two years ago, but the program was never implemented amid a resulting controversy. The Washington Post is reporting that customers are unhappy about the possible inconvenience of the screening.