Some of the biggest measures -- such as airport-style metal detectors at bus terminals and wanding each piece of baggage -- would take more resources than companies can afford on their own, said Eron Shosteck, a senior vice president for the American Bus Association.
Shosteck said the American Bus Association has been asking the Department of Homeland Security for funds for more than six years. While DHS has awarded nearly $11.2 million in grants to independent bus operators this year, he said, buses need $25 million for next year, according to Shosteck.
"They need to be doing more," Shosteck said.
Wambaugh, the Greyhound spokesperson, echoed that. "There is still much to be done with respect to significantly expanding our security program, but it requires more financial resources that cannot be addressed by the private sector alone."
ABC News contacted the DHS, but the agency has not yet provided comment.
Megan Chuchmach is a 2008 Carnegie Fellow at ABC News in New York. She recently graduated from Columbia University's Graduate School of Journalism.