I remember during the Cuban Missile Crisis, we would NEVER let the gas tank get lower than half in case we had to get out of town. Being a little tike, I don't know if many had much plans beyond that or if they even thought about foodstuffs or other survival. However, many built bomb shelters that probably wouldn't have sustained much of anything, but then we all knew that crouching under our school desks would be the saving of America.
Heck, I don't let our gas tanks get below 1/2 tank, either...and keep six weeks' worth of food and water on hand, as well.