The Street Centerlines layer is a series of lines (or polylines) digitized along the center of streets. These lines connected at intersections creating a street network. Each line carries attributes for the street name, address range, road class, jurisdiction and other data items.

Street centerlines are one of the most fundamental and useful G.I.S. layers. There are many applications that require accurate and comprehensive street centerlines datasets.
Main applications:
Networking (routing, navigating etc.)
Geocoding - assigning a geographic location to an address based on the address ranges stored in the street data.