All states have DUI laws they consider “intoxicated per se” to any driver with a blood alcohol concentration above the limit set (currently 0.08 in all states). This means that drivers with a blood alcohol concentration of 0.08 or higher are legally intoxicated and poisoning tests are needed.
All states also have laws on “zero tolerance” policy aimed at children that the legal age for drinking drivers. These laws penalize people under 21 for driving a vehicle with any trace of alcohol in the body (a concentration of alcohol in blood exceeds 0.0) or with negligible blood alcohol levels, such as 0.01 or 0.02.
Remember that a driver can be arrested and convicted of DUI even without evidence of intoxication , when there is evidence that their capabilities were diminished while driving. For example, you can plead guilty to an offense of DUI a driver with a level of alcohol concentration in blood of 0.06 if the arresting officer states that watched the vehicle veered awkwardly and the driver showed signs of slurred speech and serious lack of attention during the subsequent interrogation at stop of the vehicle.