This layer was created for addressing, routing applications, base maps, and general mapping purposes, both for internal and external use. This line layer contains centerlines of all paved and unpaved roads, ramps, and bridges in the City of Cambridge. Each centerline segment contains attributes including street name, street type, address ranges, and one-way designations.

For more information and download links see:
http://www.cambridgema.gov/gis/gisdatadictionary/trans/trans_centerlines.aspx