It's a function of the urban design. In neighborhoods that are planned around residences having off-street parking, it's not necessary, and many have a blanket

It's a function of the urban design. In neighborhoods that are planned around residences having off-street parking, it's not necessary, and many have a blanket "no overnight street parking" rule. In others, almost no residences have off street parking and there are few if any commercial garages, so everyone parks on the street. Reducing the curb space available for parking forces the least patient street parkers to give up their cars.