DUI requires evidence that a person is impaired by a drug. A person who is not under the influence of a drug, but is tired, emotionally distressed, distracted or otherwise unable to safely drive a car due to factors other than the use of a drug is not guilty of DUI.

There are other charges applicable to that situation, namely reckless driving, and in some states a lesser offense of careless driving. Schawb was additionally charged with reckless driving, a charge that does fit his alleged conduct.