§ 4-3. Construction standards.

(a)

Each street designated by the planning commission as an arterial or commercial industrial street shall be constructed with complete curbing, guttering, and subsurface drainage. Minimum width shall be 30 feet from back of curb to back of curb. The street shall be of LDOTD Class A concrete no less than eight inches thick with a cross slope of no less than one-quarter of an inch to a foot. The base course for this pavement shall be 31 feet in width on six percent minimum by volume lime conditioned soil eight inches thick, or treated as recommended by a qualified engineer based on soil testing of the native soil material. Curb and gutter construction shall be of Class A Portland Cement concrete. The longitudinal slope of the street gutter shall be 0.3 percent minimum.

(b)

Each street designated by the planning commission as a collector, local, or marginal access street shall be constructed with complete curbing, guttering, and subsurface storm drainage. Minimum width shall be 27 feet from back of curb. Cross slopes and longitudinal slopes shall be the same as in (a) above. Curb and gutter shall be of Class A concrete. The street surface shall be a minimum of 23 feet wide two inches thick asphaltic concrete wearing surface on an eight inch soil cement base at least 24 feet wide. The soil cement shall be processed into a lime treated soil 12 inches thick with lime/soil proportion determined by a qualified engineer based on soil testing of the native soil material. Lime treatment may be waived for asphaltic concrete surfaced streets if it can be demonstrated to the satisfaction of the planning commission that the in-situ soil Plasticity Indecies are everywhere less than 15 or,

(c)

At the discretion of the planning commission the street surface may consist of a minimum of 22 feet wide two inches thick asphaltic concrete wearing surface on an eight inch soil cement base at least 23 feet wide. Cross slope shall be the same as in (a) above. The soil cement shall be processed into a lime treated soil 12 inches thick with lime/soil proportion determined by a qualified engineer based on soil testing of the native soil material. Lime treatment may be waived for asphaltic concrete surfaced streets if it can be demonstrated to the satisfaction of the planning commission that in-situ soil Plasticity Indecies are everywhere less than 15. A graded road bed at least 26 feet wide shall have a swale ditch on each side with a longitudinal slope not less than 0.10 percent, a foreslope not steeper than two feet horizontal to one foot vertical and back slope not steeper than one and one-half feet horizontal to one foot vertical. Required culvert pipe sizes to ultimately be installed under driveways must be specified on the preliminary and final plat of the subdivision and included in the subdivision covenants.

(d)

Where boulevards are constructed each lane of a street designated as a local or collector street shall be no less than 22 feet from back of curb to back of curb, with a neutral ground of at least 12 feet. Each lane of a boulevard designated as an arterial street shall be no less than 25½ feet from back of curb to back of curb, with a neutral ground no less than 30 feet. Construction shall be commensurate with the traffic designation by the planning commission.

(Ord. No. 939, 11-10-97)