Minimum.
Blocking traffic isn't simply blocking traffic; based on what we've seen, the person in a stopped vehicle could be the target of violence.
So the motorist is left with two choices: Calmly stay in the car surrounded by the mob and run the risk of being beaten or killed, or run someone (or several people) over in order to get away.
No one in their right mind today will stop when they see a crowd on the road trying to stop you