A Curiosity Question

We all know that overnight alternate side of the street parking exists in Hudson so that the street sweeper can come through in the dead of night to clean the streets. So why, in recent weeks, has the street sweeper been coming through in the late morning, when the alternate side rules are no longer in effect and cars can be parked legally on either side of the street?

This picture was taken on Allen Street at 11:16 a.m. this morning.