One of my friends had her teenaged daughters just above the street when the subway blew in London. And you know, there's kids all over the place here," she said. "I would hope it makes a difference, but I don't know. The explosives can be so small."
She also says she isn't planning to stop riding public transportation anytime soon. "No, because I have to get where I'm going, so I get on it. You gotta do what you gotta do."
U.S. transportation officials say the extra security measures will remain in place untill federal officials decide to lower the threat level for mass transit systems.