Is street a proper noun or common noun?

The noun 'street' (lower case s) is a common noun, a general Word for any public thoroughfare, usually paved, in a village, town, or city.

The noun 'Street' (capital S) is a proper noun, part of the name of a specific street (Main Street), the name of a person (DELLa Street, secretary to fictional attorney, Perry Mason), or the name of a thing "On The Street Where You Live" (song by Lerner and Loewe).