"I honestly thought my time was up," one London commuter said.
Those images from struck a chord with many Americans who take trains or buses.
But are they afraid now? ?
To get a sampling of feelings, The Early Show correspondent Melinda Murphy went to New York's Times Square, the heart of one of the busiest commuter areas in the nation.
Each day, Murphy reports, people take more than 25 million trips on commuter trains, buses and subways throughout the United States, a third of them in and around New York.
Of those, most live in the New York metropolitan area, many are tourists, and all are faced with the same question: Should they be in fear while on trains and buses?
One woman told Murphy she didn't hear about London until she got to work: "Otherwise, I know I would have been pretty worried about it."
A teen said, "It's scary, man, to ride the train knowing that you could get bombed."
Another man remarked, "I am concerned yes. But, I mean, we still have to do what we have to do."
But should people worry, Murphy wondered.
It's hard not to, she says. After all, some of the deadliest terrorist attacks since September 11th have happened on mass transit systems around the world.
Yet, William Millar, president of the American Public Transportation Association insists, "Public transit in America is one of the safest forms of transportation. It's very important that our customers around the country be vigilant, (but) they should not be fearful. Riding the public transit is a safe experience most of the time."
In fact, in the wake of what happened in London, mass transit systems across the U.S. have .
Even so, Murphy observes, commuters are wary.
Asked if he thinks an attack like the ones in London and Madrid are going to happen in the U.S., one man admitted, "We all, in the back of our minds, think that. But you can't live your life like that."
"The reality," says author Dr. Marc Siegel, "is that the risk of this happening to any one of us individually is extremely remote. And that's what we have to keep in mind."
Siegel wrote a book about fear titled "False Alarm."
He says, "It's very healthy to be savvy and to be aware, but fear is not healthy unless it's in response to an imminent danger."
In fact, says Murphy, unfounded fear can actually be destructive and can even make you sick. Staying calm is important, especially for children.
"Are you worried about riding the subway in New York?" Murphy asked one boy.
"A little bit?"
"What worries you?"
"That they would explode or something like that."
"Parents know that they have to set a good example for their children," Siegel says. "So don't act afraid. If you're not feeling afraid, your children won't feel afraid."
But not everybody reacts with fear.
One woman commented to Murphy, "The terrorists are doing what they're doing. Why aren't we able to stop it? I'm more angry than frightened. I'm very angry."
So how should people manage their emotions?
It turns out, Murphy says, the key is information.
"We should be informed," Siegel suggests. "We are better off informed. We are calmer when we know what is going on, but don't obsess on this. …Stick to your regular activities. Keep working."
One commuter couldn't agree more, telling Murphy, "You have to continue to live your life, and if you don't do that, they win."
That sentiment was echoed by many of the people Murphy spoke with Thursday, and Times Square was bustling with commuters Friday morning. Business as usual.