Streets and Highways Code § 33138

The authority may sell bonds at a price below the par or face value, provided that the discount on any bonds so sold shall not exceed 8 percent of the par value thereof.

The interest rate on the bonds shall not exceed 8 percent, payable semiannually. The sale shall be conducted in compliance with Chapter 10 (commencing with Section 5800) of Division 6 of Title 1 of the Government Code.