(b) If a local educational agency determines that the purchase or contracting of a zero-emission schoolbus is not feasible due to both terrain and route constraints, the local educational agency may request a one-time extension for a term not to exceed five years, in order to meet the requirements in subdivision (a), provided that both of the following conditions are met:

1. (1) The local educational agency can reasonably demonstrate that a daily planned bus route for transporting pupils to and from school cannot be serviced through available zero-emission technology in 2035.
2. (2) The State Air Resources Board, in consultation with the department and the State Energy Resources Conservation and Development Commission, receives and evaluates a local educational agency’s request, and grants a one-time extension based on the local educational agency reasonably demonstrating the condition in paragraph (1).

(c) Commencing January 1, 2040, if a frontier local educational agency determines that the purchase or contracting of a zero-emission schoolbus is not feasible due to both terrain and route constraints, the frontier local educational agency may request annual extensions, with the last extension expiring on January 1, 2045, in order to meet the requirements in subdivision (a), provided that both of the following conditions are met:

1. (1) The frontier local educational agency can reasonably demonstrate that a daily planned bus route for transporting pupils to and from school cannot be serviced through available zero-emission technology in the period in which the annual waiver is sought.
2. (2) The State Air Resources Board, in consultation with the department and the State Energy Resources Conservation and Development Commission, receives and evaluates the frontier local educational agency’s request, and grants an annual extension based on the frontier local educational agency reasonably demonstrating the condition in paragraph (1).

(d) For purposes of this section, the following definitions apply:

1. (1) “Frontier local educational agency” means a local educational agency that meets either of the following conditions:

   1. (A) The total number of pupils in average daily attendance at all of the schools served by the local educational agency is fewer than 600.
   2. (B) Each county in which a school operated by the local educational agency is located has a total population density fewer than 10 persons per square mile.
2. (2) “Local educational agency” means a school district, county office of education, or charter school.