Per Se Laws

Standardized field sobriety tests – the walk-and-turn, one-legged stand and horizontal gaze nystagmus tests – are intended to be used by police officers to determine probable cause that a driver is under the influence of alcohol. When a police officer uses one or more of these tests to determine that the driver is in fact most likely under the influence of drug or alcohol, which is called determining per se intoxication, the next test should be a breathalyzer, blood, or urine test to determine blood-alcohol content (BAC). This is the ratio of blood to alcohol in a person’s system.

Although you may be lucky enough to not show any effects of alcohol, if the officer still determines that there is probable cause or just suspicion that you are under the influence of drugs or alcohol, then you are considered per se intoxicated and it does not matter if you passed field sobriety tests or did not show any affects of alcohol. Per se intoxication means it is illegal to drive with a blood-alcohol concentration at or above the legal limit for that state. In more than half of the states the legal limit is .10 percent, but it does vary between states. If your BAC is tested and you are above that state’s legal limit, you are considered by the officer to be per se intoxicated and you will be placed under arrest for driving under the influence.

If you refuse to take a chemical test, you are likely to be arrested for ‘per se intoxication.’ This means that if you refused chemical testing or to cooperate with field sobriety tests, you can still be arrested if the officer has probable cause to believe you are intoxicated and a danger to the public or yourself. These reasons may be that you were weaving, made an illegal lane change, drove without headlights, or any number of other infractions. The police cannot pull you over for no reason at all, but don’t think that it is a difficult situation for them to find a reason. You can also be arrested if you cannot produce a driver’s license or proof of insurance. Under implied consent laws, in most states a driver’s license is automatically suspended for up to one year, even if the motorist is ultimately not found guilty of DUI.