(a) The proceeds of bonds issued under this subchapter may only be used to pay the cost of the project for which the bonds were issued.
(b) The county shall disburse the proceeds of the bonds in accordance with any restrictions provided in the order authorizing the bonds.
(c) The bondholders have a lien on the proceeds until the proceeds are applied.
(d) The bond proceeds, pending their use for the construction of the project, may be invested in direct obligations of the United States having maturities not more than 91 days from the date of investment.