California Code, Health and Safety Code - HSC § 1797.120

(a) The authority shall develop, using input from stakeholders, including, but not limited to, hospitals, local EMS agencies, and public and private EMS providers, and, after approval by the commission pursuant to Section 1799.50, adopt a statewide standard methodology for the calculation and reporting by a local EMS agency of ambulance patient offload time.

(b) For the purposes of this section, “ambulance patient offload time” is defined as the interval between the arrival of an ambulance patient at an emergency department and the time that the patient is transferred to an emergency department gurney, bed, chair, or other acceptable location and the emergency department assumes responsibility for care of the patient.