The Washington Metro system will start randomly inspecting bags at subway entrances within the next few days.
Metro says the program is based on similar policies in Boston and New York and is just another part of the system's continuous effort to improve security.
Metro police and officers from the Transportation Security Administration will randomly select bags or packages to check for hazardous materials. They'll use special technology and K-9 units trained to detect explosive materials.
Metro says items generally won't have to be opened for inspection unless the equipment suggests a need for a closer look.
If riders refuse bag searches, they won't be able to bring their items into the system.