California Vehicle Code definition of
Residence district
CVC Section 515. A "residence district" is that portion of a highway and the
property contiguous thereto, other than a business district, (a) upon
one side of which highway, within a distance of a quarter of a mile,
the contiguous property fronting thereon is occupied by 13 or more
separate dwelling houses or business structures, or (b) upon both
sides of which highway, collectively, within a distance of a quarter
of a mile, the contiguous property fronting thereon is occupied by 16
or more separate dwelling houses or business structures. A
residence district may be longer than one-quarter of a mile if the
above ratio of separate dwelling houses or business structures to the
length of the highway exists.
CVC Section 235. A "business district" is that portion of a highway and the
property contiguous thereto (a) upon one side of which highway, for a
distance of 600 feet, 50 percent or more of the contiguous property
fronting thereon is occupied by buildings in use for business, or (b)
upon both sides of which highway, collectively, for a distance of
300 feet, 50 percent or more of the contiguous property fronting
thereon is so occupied. A business district may be longer than the
distances specified in this section if the above ratio of buildings
in use for business to the length of the highway exists.
CVC Section 240. In determining whether a highway is within a business or
residence district, the following limitations shall apply and shall
qualify the definitions in Sections 235 and 515:
(a) No building shall be regarded unless its entrance faces the
highway and the front of the building is within 75 feet of the
roadway.
(b) Where a highway is physically divided into two or more
roadways only those buildings facing each roadway separately shall be
regarded for the purpose of determining whether the roadway is
within a district.
(c) All churches, apartments, hotels, multiple dwelling houses,
clubs, and public buildings, other than schools, shall be deemed to
be business structures.
(d) A highway or portion of a highway shall not be deemed to be
within a district regardless of the number of buildings upon the
contiguous property if there is no right of access to the highway by
vehicles from the contiguous property.