Blood Alcohol Content
The central issue in almost every DUI defense is whether a person's blood alcohol
content (BAC) is equal to or greater than the statutory minimum. If blood alcohol content is above the minimum, a person are considered
legally intoxicated and subject to DUI penalties. In the United States,
every state has a DUI/DWI statute that sets the legal BAC threshold at .08%.
What is Blood Alcohol Content?
Blood alcohol content is the amount of alcohol
in your blood. A BAC test actually measures the weight of alcohol in a
certain volume of your blood, expressed as a percentage. The greater the
level of alcohol in your blood, the more your driving will be impaired.
Although most state DUI laws provide that a blood alcohol content
of .08% is considered legally intoxicated,
some studies show that a blood alcohol content as low as .02% affects a person's ability to drive and increases the likelihood of an accident. The
probability of a crash begins to increase significantly at a blood alcohol
content of .05% and climbs rapidly above .08%.
How Is Blood Alcohol Content Measured?
BAC is usually determined by breath, blood, saliva or urine testing,
which is typically performed shortly after being stopped for suspicion
of DUI. Although police officers often use various field sobriety tests, these road tests only measure your reflexes
and abilities, not your BAC.
If you fail a field sobriety test,
you can still be convicted of a DUI offense even if your BAC is below
.08%.
Blood testing is generally considered the most accurate method to determine your BAC. Blood
testing usually involves the drawing of your blood by a doctor or other
qualified medical professional. A breath test with a breathalyzer is the most common type of
blood alcohol test performed by law enforcement officials. A breathalyzer
measures the alcohol level in your breath from the lungs.
Blood Alcohol Content and the Law
Although .08% BAC is now the law in all 50 states, there are even
lower thresholds for younger drivers in some states. Some
states like Illinois, have a zero tolerance for underage drinking and driving policy. If you are under 21 and have
any level of alcohol in your blood, even .01%, you may face a DUI or DWI conviction.
The only way to accurately determine your BAC is to take
a breath, blood, urine or other chemical test, but there are some
general rules of thumb that help estimate BAC, depending
on weight and the mount of alcohol ingested. An average 170-pound
man must have more than four drinks in one hour on an empty stomach to
reach a .08% BAC. A 137-pound woman would reach .08% BAC after about
three drinks in an hour on an empty stomach.
These figures are rough estimates. Depending
on your weight, metabolism, amount of food eaten and other factors,
you may be legally intoxicated even if you have fewer drinks in your system
than the average man or woman could legally handle. There are also home breathalyzer kits that allow you to measure your
own BAC. These tests can be highly inaccurate, and it's not encouraged to rely on them.
Speak to a DUI Lawyer about Blood Alcohol Content
If you have a DUI case pending against you, speak to a DUI attorney about your DUI defense today. Call 877-349-1311 or fill out a free DUI case evaluation form to connect with a DUI attorney who can offer you legal advice.
The above summary of blood alcohol content is by no means all-inclusive and is not legal advice. Laws may have changed since our last update. For the latest information on blood alcohol content laws, speak to a DUI attorney in your area.
