(a) The provisions of section 1251 of this title shall not apply to directional signal lamps of a type approved by the Commissioner.
(b) All persons with motor vehicles equipped as provided in subsections 1252(a) and (b) of this subchapter shall use the sirens or emergency warning lamps, or both, only in the direct performance of official duties. When any individual other than a law enforcement officer is operating a motor vehicle equipped as provided in subsection 1252(a) of this subchapter, the emergency warning lamps shall be either removed, covered, or hooded. When any individual other than an authorized emergency medical service vehicle operator, firefighter, or authorized operator of vehicles used in rescue operations is operating a motor vehicle equipped as provided in subsection 1252(b) of this subchapter, the emergency warning lamps shall be either removed, covered, or hooded unless the operator holds a senior operator license.