(a) No person shall drive a commercial motor vehicle, as defined in Ohio R.C. 4506.01, or a commercial car or commercial tractor, as defined in Ohio R.C. 4501.01, while the person's ability or alertness is so impaired by fatigue, illness, or other causes that it is unsafe for the person to drive such vehicle. No driver shall use any drug which would adversely affect the driver's ability or alertness.
(b) No owner, as defined in Ohio R.C. 4501.01, of a commercial motor vehicle, commercial car or commercial tractor, or a person employing or otherwise directing the driver of such vehicle, shall require or knowingly permit a driver in any such condition described in division (a) of this section to drive such vehicle upon any street or highway.
(ORC 4511.79)