Where i live there is a lot of snow and when the snow on the streets freeze they come around the snow plows which also spread salt on the street. Salt melts the ice. Which is why there are puddles on the street and not on the steps.
Yeah... I guess you live in California or Florida or somewhere south like that. Roads are sprayed with salt or sand, that's why there are puddles (chemistry 101). The water freezes 'cause it's got no contaminants in it (or very very little). Same reason why there's snow around town.
was the water/puddle moving? If so, it's a lot harder to freeze...also, the street may be warmer than the steps, or maybe it's water because of the friction of tires going over it?
This is not a slip-up. Concrete surfaces freeze much quicker than asphalt surfaces. That's why some bridges have warning signs that say "bridge may be icy". That is why there were puddles instead of ice.
This isn't a slipup because when you see Kevin splashing through water, he is IN the Murphy's house accross the street. He is in the basement. Remember when Marv left the water running? It flooded the house. So the water should not be frozen because it is inside. And as far as I remember, you never see him running through puddles in the street anyway, only in the Murphy's basement.