"There was a study done about a year ago. Almost everyone knows we have the siren alert, but almost nobody knows what they mean or how you're supposed to respond," said University of Hawai'i at Hilo oceanography professor Walter Dudley, author of the book "Tsunami!"

The alert means you should turn on a radio or television to find out what the emergency is and how to respond to it.

If it is a tsunami alert, you are urged to check the maps in the phone book to find out if you're in a tsunami inundation zone, and if so, to get out of it. If you see ocean water receding, or hear the sound of rushing water, don't wait. It's that simple. Head inland by as direct a route as possible.

But in the 1994 tsunami alert, people traveled laterally within the tsunami zone to get from one place to another, they clogged roads trying to get to their homes or to vantage points to view the tsunami, and a few actually traveled toward the coast. Many were caught in traffic jams on coastal roads. Many were unable to get out of tsunami zones because they were stuck in traffic.

Waikiki is such a congestion problem that it's the only place where Civil Defense authorities don't want people to try to leave. They recommend "vertical evacuation." Reinforced concrete buildings survive tsunamis well, and Waikiki residents and visitors are urged to get to the third floor or higher.

State Civil Defense tsunami program manager Brian Yanagi said that Americans' addiction to their cars is part of the problem.

"In Waikiki, it's the practical issue of thousands of tourists trying to take their cars, and I know if they leave, they'll want to take their cars," he said.

Not only tourists behave that way. Kailua resident Fred Barnett suggested that evacuation of Kailua and Lanikai would be gridlocked because of road and sewer construction projects.

"Nobody would get out of here alive. Pity those poor Lanikites," Barnett said.

One recommendation from emergency authorities is to stop thinking about your car. In Lanikai, for instance, the road out of the area is within the tsunami zone. People there should simply head inland and uphill. In most parts of Lanikai, a block mauka is sufficient.

If you're outside a tsunami zone, don't make potential traffic worse.

"Stay put. Don't get in your car," Yanagi said.

"Only in tsunami evacuation zones should people be moving inland, and you can even walk out," he said.

Dudley said most parts of Hawai'i are geographically constructed so that even a large tsunami won't go very far inland.

"We don't live on flat islands where there's nowhere to hide. In the tsunami zone, it's real dangerous, but just outside of it, you're pretty safe," he said.

One of the greatest threats is a locally generated tsunami, like the one caused by the 1975 Kalapana earthquake, because the tsunami follows the quake with little delay. But even in that case, Big Island residents have the additional warning of feeling the quake. If you feel a quake and you're near the water, start walking, Dudley said.

"In 15 minutes you can walk a mile. People shouldn't live in fear. They should just be informed."