(a) Installation. Curbs shall be required on all streets in accordance with the construction standards established herein.
(b) Construction.
(1) Curb Alternate No. 1. Straight concrete curbs shall be twenty-four (24) inches in depth, five (5) inches wide at the top and six (6) inches wide at the base and shall have an exposed face of six (6) inches or an acceptable equivalent. Expansion joints shall be provided at least every twenty (20) feet.
(2) Curb Alternate No. 2. Combination straight concrete curb and gutter shall be twenty-four (24) inches wide at the base, fifteen (15) inches high in the back and have an exposed face of six (6) inches or an acceptable equivalent. The curb shall be five (5) inches thick at the top and the gutter portion shall be pitched back to the face for proper drainage.
(3) Curb Alternate No. 3. Combination rolled concrete curb and gutter shall be permitted only on local streets. Curbs shall be twenty-four (24) inches wide at the base, thirteen (13) inches high in the back and have an exposed face of four (4) inches or an acceptable equivalent. The radius of the rolled face shall be a minimum of ten (10) inches.