They don't seem to be the brightest ducks....coming home too early and resting in the path of oncoming traffic based on the tire marks
Other than coming back too early, they're actually pretty smart. They hang out where they do because it's where most people go in and out of the supermarket. Very few people use the entrance on the other side. The ducks want to be where the people are passing because some of those people will feed them.
In fact, although the ducks ignore most people, they recognize and enthusiastically greet the people who regularly feed them. They also evaluate other people for the likelihood of handouts. If you crouch down to their level, or even stand and smile at them, they'll walk up to you
en masse.
They also walk up to old people in general and children in general, presumably because they've learned that old people and children are more likely to feed them. They also recognize the store workers who bring the garbage around to the rear of the store at the end of every shift.
As for the cars, they do move out of the way when a car or truck needs to get down the alley. They just clear a path through the flock and fill it back in again when the vehicle passes. They like keeping that wing-span distance between them. They don't get much closer together nor farther away than that.
The way things are going, it may be a couple of weeks before the river thaws enough for duckly duties. We're still dropping down below 0 F most nights and staying in the low to mid teens during the day. We had one day this past week when the temperature soared to a sweltering high of 33 F, but before that, it has been consistently below freezing for about three weeks.
Rich