Section 24-241. Emergency signal devices

(a) No person shall operate or use
  or cause to be operated or used any emergency signal device,  except  on
  an  authorized  emergency  vehicle  when  such  vehicle is in the act of
  responding to an emergency; provided  that  such  device  shall  not  be
  operated  for  a  period  of time longer than is necessary to respond to
  such emergency. Notwithstanding the foregoing, such a device on a  motor
  vehicle  shall be lawful if designed and used solely as an audible motor
  vehicle burglar alarm in accordance with section  24-238  and  a  device
  attached  to  a  vehicle for the purpose of providing an audible warning
  when the vehicle is backing  up  shall  be  permitted  even  though  the
  audible warning may consist of a gong or bell sound.
    (b)  No  person  shall  operate  or permit to be operated an emergency
  signal device installed on an authorized  emergency  vehicle  that  when
  operated  at  the  maximum  level  creates a sound level in excess of 90
  dB(A) when measured at a distance of fifty feet from the center  of  the
  forward  face  of such vehicle. Within one year after the effective date
  of this subdivision and every two  years  thereafter,  emergency  signal
  devices  installed  on authorized emergency vehicles shall be tested and
  certification shall be submitted, in a form approved by the  department,
  that  such  devices  meet the standard set forth in this subdivision for
  operation at maximum level. Notwithstanding  the  foregoing  provisions,
  where compliance with the provisions of this subdivision would create an
  undue hardship, the owner or operator of an authorized emergency vehicle
  may  submit  a  plan to the commissioner for emergency signal devices to
  meet the standard set forth in this subdivision within two  years  after
  the  effective  date  of  this subdivision. Such plan shall be submitted
  within one year after the effective date of this subdivision in lieu  of
  the   required  certification.  This  subdivision  shall  not  apply  to
  authorized emergency vehicles of the police department, fire  department
  or authorized emergency vehicles responding to medical emergencies.