Last year was the first one in a while that made Americans stop, pause, and ask themselves if they could survive the end of the world. Whether you're a Silicon Valley billionaire or a regular schmo making minimum wage, it's worth considering a bug out bag in 2018—some insurance against the apocalypse. If you're an entire American city, however, your prepper sack needs more than batteries and a good knife. Things are shifting quickly in the world of urban mobility.