The "per se" alcohol concentration in North Dakota is 0.08 percent. For CMV Drivers, the alcohol concentration is 0.04 percent, and for operators under 21 years of age, the alcohol concentration is 0.02 percent.
If someone is operating a vehicle with lower alcohol concentrations than those listed, that person may be charged with DUI if under the influence of alcohol and/or drugs renders them incapable of safely driving.
ND Century Code Chapter 39-08 denotes regulations governning operators of motor vehicles, see section 1 regarding substance use and driving.