(1) The provisions of this chapter do not apply with respect to the use of zero emission buses purchased by a transit agency or by a federally recognized Indian tribe to provide public transportation services.
(2) For the purposes of this section.
(a) "Transit agency" means a city-owned transit system, county transportation authority, metropolitan municipal corporation, public transportation benefit area, unincorporated transportation benefit area, or regional transit authority.
(b) "Zero emissions bus" means a bus that emits no exhaust gas from the onboard source of power, other than water vapor.
(3) The exemption under this section expires after the last day of the calendar month immediately following the month the department determines the total amount of exemptions under this section and RCW 82.08.994 issued reaches or exceeds $14,000,000.