California Code, Streets and Highways Code - SHC § 2558

(a) Subject to subdivision (b), a service authority may issue revenue bonds pursuant to Chapter 6 (commencing with Section 54300) of Division 2 of Title 5 of the Government Code, or Chapter 5 (commencing with Section 4950) of Part 3 of Division 5 of the Health and Safety Code, as nearly as practicable, for the implementation and maintenance of a motorist aid program and shall pledge revenues to be received from fees referred to in Section 2555 as security for the payment of principal or of interest or other amounts due on those revenue bonds.  In addition, a service authority that has entered into one or more leases or lease-purchase agreements for facilities of a motorist aid program may also pledge, as security for the payment of amounts due under the leases or agreements, revenues to be received from those fees.  The pledge of revenues provided for in this subdivision shall be a first and prior lien and, without any action other than the adoption by the members of a resolution providing for the pledge, the lien of the pledge shall attach and become perfected as to each fee imposed pursuant to Section 9250.10 of the Vehicle Code as and when the fee becomes due and payable.  However, if a service authority has, at the same time, existing obligations under one or more issues of revenue bonds, one or more leases or lease-purchase agreements, or both, the respective priorities of the liens of pledges of revenue shall be determined on the basis of the respective dates on which resolutions providing for those pledges were adopted, with the highest priority being accorded the pledge of revenues provided for in the earliest of those resolutions.  Bond proceeds shall not be used for operation of a motorist aid system of call boxes.

(b) A service authority may issue revenue bonds for each county within its jurisdiction.