I dont know how the snow plowing system works, could you explain it to me?

I live in central Jersey, and I’ve never seen such half-ass snow plowing before. One street would be cleared, but they would miss two side streets or do none at all. What is the point of clearing a road, but not clearing the road that allows people to leave their houses? The plows were out and about, but were they just not doing anything?

Some main roads were not plowed until two days after it stopped snowing as well. So instead of just saying that people didn’t do their job, I’d like to fully understand the situation so I don’t make a poor judgment. So what are some reasons one town would do horribly plowing, and another was very efficient?