Understanding DUI Safe Harbor Laws
There are two types of DUI safe harbor laws. The modern trend is against both, but be sure to check the laws of your jurisdiction for applicability.
The first type protects people who wish to use their vehicle as a "shelter". Defined as those who began to drive then pulled off the side of road after realizing they were too impaired. Also includes those who wish to "sleep it off" in their cars before driving at all. In some states, your permitted to use your car as "safe harbor" - a shelter - shielding from prosecution. The prosecutor requires to prove in DUI case that the person was driving or in physical control of vehicle. In safe harbor situations it is harder to prove since the suspect is not driving when their approached by the police. The idea is to encourage people to pull over to prevent them from harming themselves or others.
The second type of safe harbor law refers to presumptions of impairment for people with a BAC (Blood Alcohol Content) under a certain limit. Remember that the legal limit for DUI is .08. Another type of "safe harbor" law is where a person with a BAC under a certain amount (for example, in Louisiana it's .05) will be let go without being charged with DUI. States with these laws presume a person with a BAC under .05 is not driving under the influence of alcohol. A person with a BAC between .05 and .08 (the legal limit) not entitled to this presumption. This type of safe harbor statute has both advantages and disadvantages - where there is a presumption of innocence there is also a presumption of guilt. Thus if your BAC is above .08, your presumed impaired.