2010 California Code
Vehicle Code
Article 3.5. Headsets And Earplugs

27400.  A person operating a motor vehicle or bicycle may not wear a
headset covering, or earplugs in, both ears. This prohibition does
not apply to any of the following:
   (a) A person operating authorized emergency vehicles, as defined
in Section 165.
   (b) A person engaged in the operation of either special
construction equipment or equipment for use in the maintenance of any
highway.
   (c) A person engaged in the operation of refuse collection
equipment who is wearing a safety headset or safety earplugs.
   (d) A person wearing personal hearing protectors in the form of
earplugs or molds that are specifically designed to attenuate
injurious noise levels. The plugs or molds shall be designed in a
manner so as to not inhibit the wearer's ability to hear a siren or
horn from an emergency vehicle or a horn from another motor vehicle.
   (e) A person using a prosthetic device that aids the hard of
hearing.