Cal. Veh. Code § 34501
(a)
(1) The department shall adopt reasonable rules and regulations that, in the judgment of the department, are designed to promote the safe operation of vehicles described in Section 34500, regarding, but not limited to, controlled substances and alcohol testing of drivers by motor carriers, hours of service of drivers, equipment, fuel containers, fueling operations, inspection, maintenance, recordkeeping, accident reports, and drawbridges. The rules and regulations shall not, however, be applicable to schoolbuses, which shall be subject to rules and regulations adopted pursuant to Section 34501.5.
The rules and regulations shall exempt local law enforcement agencies, within a single county, engaged in the transportation of inmates or prisoners when those agencies maintain other motor vehicle operations records which furnish hours of service information on drivers which are in substantial compliance with the rules and regulations. This exemption does not apply to any local law enforcement agency engaged in the transportation of inmates or prisoners outside the county in which the agency is located, if that agency would otherwise be required, by existing law, to maintain driving logs.
(b)
(2)
(3) Regulations adopted pursuant to this subdivision do not apply to the following:
(A) The transportation of explosives in an authorized emergency vehicle, as defined in paragraph (1) of subdivision (b) of Section 165, when operated by a peace officer, as defined in Sections 830.1 and 830.2 of the Penal Code, under the following conditions:
(c)