Geeta Citygirl just figured something was wrong with her phone when she realized the greetings she was sending as the ball dropped New Year's Eve weren't getting through.

In Los Angeles, a half-dozen New Year's text messages bounced back to Reggie Cameron on Wednesday, more than 24 hours after he thought he sent them out.

In fact, so many people tried to send text messages on New Year's Eve that networks got jam-packed and many of the missives arrived hours later — or not at all.

"Think of any traffic artery during rush hour: You have a large number of people who are trying to access it at the same time," said Joe Farren, assistant vice president of public affairs for CTIA-The Wireless Association, a wireless industry group. "It's really no different with regard to wireless networks."

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Millions and millions of messages did get through New Year's Eve, and a minor delay in a holiday wish is hardly the end of the world.

But there have been multiple occasions in recent years when getting in touch with loved ones was more vital — the Sept. 11 attacks, the 2003 blackout, Hurricane Katrina.

"What happens where there is an emergency?" asked Scott Midkiff, professor of electrical and computer engineering at Virginia Tech. "This has been a big problem with the voice cellular system. It will probably become more of a problem with text messaging."

The cell phone carriers say they are working to expand their systems' capacity. Jeffrey Nelson, spokesman for Verizon Wireless, said the company invests almost $6 billion annually in the wireless network.

But the number of cell phone subscribers in the U.S. nearly doubled between the end of 2001 and the end of 2006, growing from 128 million to 233 million users, Farren said.

Analysts said last month that Americans may have spent more in 2007 for the first time on their cell phones than on land lines and pay phones. And people are using their cell phones in growing ways — for text messages, video messages, e-mail and Web access.

In an emergency, it could be a concern, Cameron said.

"I didn't have a connection using cell phones for several days, and that was really frightening," he said of living in New York after the Sept. 11 attacks. "I didn't talk to my parents for a week and a half."

"It's definitely a really big question mark," said Rajan Shah, who sent his New Year's text messages before the clock struck midnight to beat the rush. "It really makes you rethink technology and whether we are able to be connected through a global catastrophe."

Text messages already use a different transmission system from cell phone calls. There may be a way to differentiate among types of information or to create a separate system for people to use in emergencies.

Farren said emergency networks in place and now being expanded allow emergency service personnel to maintain voice cell phone service in times of need.

But that doesn't help average Joe trying to find Mrs. Joe.

The next step may be some consumer education, Farren said.

"In an emergency situation, you really should stay off your phone" if possible, he said.

Emergencies by definition are so unusual that building a full backup network could be cost-prohibitive, Farren said.

"If you're asking everyone to spends billions to billions to build a secondary network, someone's got to pay for it," Farren said.

But the wireless field is constantly changing, he noted. "As innovation continues, I'm sure some of these questions will be addressed."

It's not a strict technology issue, Midkiff said.

"It's people having to think a little bit differently about how you communicate," he said. "Maybe there's a need for some different models."