§ 509-k. Ill or fatigued operator. No driver shall operate a bus and a
motor carrier shall not permit a driver to operate a bus while the
driver's ability or alertness is so impaired, or so likely to become
impaired, through fatigue, illness or any other cause, as to make it
unsafe for him to begin or continue to operate the bus. At the request
of the driver or the motor carrier such illness, fatigue, or other cause
shall be certified by a qualified physician. However, in a case of
grave emergency where the hazard to occupants of the bus or other users
of the highway would be increased by compliance with this section, the
driver may continue to operate the bus to the nearest place at which
that hazard is removed.