The following vehicles are exempt from licensure under this subtitle: Vehicles, typically referred to as wheelchair vans, equipped with a hydraulic lift used exclusively for transporting, in wheelchairs, patients who do not require equipment or trained personnel available in an ambulance; Ambulances owned by, operated by, or under the jurisdiction of a unit of State or federal government, a political subdivision of the State, a volunteer fire company, a volunteer ambulance company, or a volunteer rescue squad; and Ambulances traveling through the State, regardless of frequency, exclusively for the purpose of interstate travel. If SOCALR believes that an ambulance operating in this State may be required to be licensed under this subtitle, SOCALR may conduct an investigation to determine whether the ambulance service or ambulance is required to be licensed.