The Federal Motor Carrier Safety Regulations require employers to ensure that their drivers operate commercial motor vehicles (CMV) safely. As such, driving while ability or alertness is impaired, or likely to become impaired, by fatigue, illness, or any other cause is prohibited. An exception is made, however, in cases of "grave emergency" where the hazard to occupants of the CMV or other users of the highway would be increased by compliance with this requirement. In such cases, the driver may continue to operate the commercial motor vehicle to the nearest place at which that hazard is removed.