I think the plan is to act fast, like within the first hour of an event. Many people will probably be in state of denial or disbelief, and may not act right away. So those first couple of hours may be critical. If there's a little warning, or immediately after a major event, my first plan is to gas up the car if the pumps are working. And definitely stay off the freeway. With earthquakes though, all bets are off. Thats why I never let the tank go below 1/2 and keep a 3 day kit in the car. Depending how bad it is, it may take that long to get home. And hopefully home is still standing.