This is the kind of sign that they (sometimes) put up before a movie shoot. This one has a lot of information, usually it is only the "No Parking" notice, like the orange one you can just see the bottom of.
View of the set (at 36th street and 10th ave). The Ford dealership is fake, they put up the signs, flags and letters in the days before.
I think these are spare cars...
10th avenue and the side streets were lined with car "extras", which were very dirty.
Flowers were camouflaged, perhaps because the disease (or something) in the movie wipes out all life.
Another view of the set. A large truck came by to spray the street with water before the shoot began.