All on the road are there and choose to put themselves at risk. Children, family, and neighbors of hard drug abusers do not choose to be at risk.
When "children family and neighbors" choose to leave their private property, they choose to put themselves at risk. When an uninvited person enters your personal property, they have tresspassed, a right they do not have. You have the right to use defensive force once someone has illegally entered your property.
Of course, you seem as if you would rather have the government punish someone for their behavior rather than let the friends and family make the choice of being around that person any longer. You know, life is full of tough choices. Make them yourself!
The children, family and neighbors of people who drink to excess, handle money irresponsibly, have multiple unprotected sex partners or drive recklessly also do not choose to be at risk. Nevertheless, they are at "physical, financial, and psychological risk" when a loved one engages in these behaviors. Where does the distinction arise?