DUI in the Commonwealth of Pennsylvania – a DUI without being above the “legal limit?!?!”

It’s important to know how operating a motor vehicle is regulated in the Commonwealth of Pennsylvania after consuming alcohol.  An explanation of this issue appropriately begins with the law that prohibits drunk driving:  Title 75 of the Motor Vehicle Code, Section 3802, “Driving under the influence of alcohol or controlled substance,” (abbreviated as 75 Pa.C.S. § 3802).

A commonly-held myth among motorists is that a driver can be guilty of a DUI (Section 3802) only if he or she was above the “legal limit.”  This is not true.  The “legal limit” is the colloquial reference to .08% Blood Alcohol Concentration (BAC). Meaning, literally, how much alcohol was present in the blood at the time of measurement.  How this “legal limit” became the “legal limit” in the Commonwealth and other American jurisdictions is a long story, but the short of it is that, decades ago, there was a significant amount of medical research compiled that demonstrated that individuals with this amount of BAC demonstrated signs of impairment that were determined unsafe for operating a vehicle.  State legislatures, such as our General Assembly, turned these medical findings into law by declaring the legislative line of .08% BAC as the “legal limit.”  From a historical perspective, it is a great example of how scientific research was translated into informed policy.

But this article is not concerned with legal limits.  Rather, it addresses how the law prohibits an impaired individual from operating a motor vehicle without any reference to a BAC.

Before diving deeper, it should first be noted that Section 3802 is lengthy and involves multiple ways to arrive at a violation for DUI.  For this reason, the purpose of this article is to explain the first section, subparagraph (a)(1), known as “General impairment,” as the remaining subsections of 75 Pa.C.S. § 3802 are better addressed in separate articles for the sake of brevity.

With that said, regarding General Impairment, prohibited by Section 3801(a)(1):

First, it must be noted that is not necessarily illegal to drink and drive.  Our commonsense and life experiences inform us that enjoying a glass of red wine with dinner at a restaurant does not make someone a criminal.  But it is equally important to note that such behavior, depending on the circumstances involved, could be a violation of Section 3802(a)(1).

Perhaps a better way to say what is illegal in the Commonwealth on this issue and specifically punishable by Section 3802(a)(1) is that it is illegal to drink too much and drive, and this can depend largely on the person, and most especially their body weight and blood volume and other complex factors unsuited for discussion here.

Section 3801(a)(1), in the legal language we would expect to find in a law, effectively prohibits the act of drinking too much and operating a vehicle.  As it states:  It is unlawful to consume “a sufficient amount of alcohol” to the extent that the person “is rendered incapable of safely driving, operating or being in…physical control of the movement of the vehicle.”  Said in simpler terms, the consumption of any amount of alcohol can be a punishable offense under the Motor Vehicle Code, provided that it renders the individual motorist unable to be a safe driver.

But who decides what is too much, you ask?

First, the individual motorist always has responsibility for determining his or her own fitness to drive after consuming alcohol, being mindful that what matters for the purposes of the law is what is being observed of that person.  Said in another way, the law does not care if the individual believed he or she was safe to drive.  The law cares only if you look like you’re impaired while operating a vehicle – at least for the purposes of this subsection.

Second - and obviously – it is a law enforcement officer, most commonly during a traffic stop, who will decide if the motorist is showing signs that he or she has had “too much.”  Again, in the most general terms and without discussing important concepts such as “reasonable suspicion” or “probable cause,” the legal question here is whether the motorist has consumed “a sufficient amount of alcohol” to the extent that the person “is rendered incapable of safely driving, operating or being in…physical control of the movement of the vehicle.”

The next question that logically follows the legal standard is “how is it determined the motorist had too much?

The short answer is that law enforcement officers, like many if not most adults in the Commonwealth, can observe the signs of impairment based on their life experiences.  The long answer is that law enforcement officers also rely heavily on their training to recognize certain behaviors through the use of various tests, such as the “walk and turn test.”  These tests are standardized and in common usage through the United States, and involve enough complexity that they, too, are more appropriately addressed in another article.

Of course, methods of observations such as these will always involve a bit of subjectivity by the person making the observation.  That is why these observations may be indicative of impairment by alcohol, but they could never be determinative of the presence of alcohol, much less impairment by alcohol.

The bottom line is that it is a MYTH that a DUI charge must involve a motorist being over the “legal limit.”