Concrete curb and gutter shall be paid per lineal foot. The unit price shall include the cost of the concrete, excavation, preparing the subgrade, subgrade treatment, setting and removing forms, backfilling, final finish, curing of the concrete and joint construction and all other labor and materials incidental to concrete curb and gutter construction. The lineal footage of the concrete curb and gutter shall be computed as the measurement along the back of the curb.