Sharraxaadda

I thought that when snow plows are moving snow if there is a park on one side of street that snow would all be plowed to that side. I came home and found a 4 foot wide windrow in front of my driveway when there is a park across the street. I have lived in this house for 36 years and this is the first time they have ever done that! Someone please explain to me why the snow was not plowed over to the park!