Impaired driving mainly results from consuming alcohol and legal or illegal drugs
Most states consider illegal intoxication as that level of impairment where one cannot operate a motor vehicle safely. Most states have laws establishing presumptive levels of intoxication. In many states, that level is .08, measured by a breathalyzer, blood, or urine test.
Drunk driving can also be proved by the arresting officer’s observations and field sobriety tests.
Field sobriety tests include walking an imaginary straight line, observing if the driver’s speech is slurred or incoherent, testing the driver’s balance, and testing the driver’s dexterity.
