It all depends on the type of SHTF event. EMP yes the cities will be hell, Cyber were the electricity goes down well all the cars and & trucks still work so I see many going to the rural areas. Sun Flare well you have 24 to 48 hours before it hits so many will leave the cities too. Civil war or civil unrest many will leave the cities. The same goes for economical collapse many will leave the cities. So an EMP or something that will happen like the next hour is what will create hell in the cities.