It's likely because people are moving to urban areas, where driving isn't as necessary, in mass. Living in a rural area you really have no choice but to drive if you want to do anything other than sit at home with your parents everyday. And rural population is dropping.

They aren't resting, they are dead. They ain't getting back up, man.

>Let the dead bury the dead

So like.. Just don't bury anybody? We just gonna start leaving bodies where they die or something, because that sounds pretty unsanitary. And if the dead start digging the dead back up I think we got some more serious matters at hand.