Thanks for your post which explicates why they are blocking the roads, PA Engineer.
It is to keep the "technicals" (those small trucks with gunmen) OUT.
This is what many on FR have tried to explain for years, that in a scenario where it all goes to hell, thugs will leave their own environs and go looking for food, ammo, and "stuff" to loot.
These people are trying to keep the Bad Guys out of their neighborhood.
BS