(1) As used in this section and ORS 368.710, “county road fund” means a separate fund in the county treasury designated to receive deposit of revenues that are dedicated to roads or road improvements.
(2) The county road fund must be used in establishing, laying out, opening, surveying, altering, improving, constructing, maintaining and repairing county roads and bridges on county roads.
(3) County funds derived from any ad valorem tax levy may not be used or expended by the county governing body upon any roads or bridges except:
(a) Funds derived from a levy within the permanent rate limit of section 11 (3), Article XI of the Oregon Constitution, or the statutory rate as provided in ORS 310.236 (4) or 310.237, if a voter-approved county serial levy dedicated to road improvements was used in determining the rate limit; or
(b) Local option taxes levied under ORS 280.040 to 280.145.