"Maintain a sense of vigilance and of awareness if you're travelling by train, by mass transit, by air," said Secretary of Homeland Security Janet Napolitano. She was at the Trenton Transit Center on Monday reminding holiday travelers to keep their eyes open.
It's a national campaign to get the public's help to stop domestic terrorists before they strike.
"During the past decade, 80% of the terrorism plots prevented in our country were direct result from citizen tips and routine police work," said Sen. Frank Lautenberg (D).
Officials point back to May when alert vendors in New York noticed a smoking car with no driver, reported it to police and helped to foil the potential bombing of Times Square.
So what kinds of things should raise a red flag?
"There might be a box that is not routinely there, there might be activity underway with an individual that appears to be very suspicious," said Lt. Col. Jerome Hatfield of New Jersey State Police Homeland Security.
Napolitano was asked a lot of questions about the controversial full-body screeners and intrusive pat-downs that have caused so many complaints at airports. Napolitano says screening methods could be modified in the future, but don't expect any changes this week.
"All of those things we are appreciative of, sensitive to, but in the end we've got to make sure that we are doing what we can and should to adequately screen passengers," Napolitano said.
Some wonder about the wisdom of screening airline passengers so closely and train passengers not at all.
"There's no screening on trains. Anyone can get on a train with any type of bag they want," said Stephanie Mackenzie of Fox Chase.
But transit police say security will be stepped up over the next few days: sniffer dogs will be patrolling train stations, response teams will be on alert and there will be increased patrols on trains and in the stations.
"We conduct random baggage inspections on our system, all over the system, we also have behavioral assessment officers that are out looking for suspicious activity," said Dep. Chief Joseph Kelly of the NJ Transit Police.