Q & A on BAC
What is “BAC”?
The amount of alcohol in a person’s body
is measured by the weight of the alcohol in a certain volume of blood. This is
called the blood alcohol concentration, or “BAC.”
Alcohol is absorbed directly through the walls of the stomach and the small
intestine, goes into the bloodstream, and travels throughout the body and to the
Alcohol is quickly absorbed and can be measured within 30 to 70 minutes after a
person has had a drink.
Does the type of alcohol I drink affect my BAC?
No! Alcohol is alcohol.
Each of the following contain the same amount of alcohol
12 oz can of beer at 5% alcohol
5 oz glass of wine at 12% alcohol
1.5 oz of 80 proof liquor at 40% alcohol
12 oz wine cooler at 5% alcohol
What affects my BAC?
A person’s BAC depends on a number
The number of drinks.
The more you drink, the higher the BAC.
How fast you drink. When alcohol is consumed quickly, you will reach a higher BAC than
when it is consumed over a longer period of time.
Women generally have less water and more body fat per pound of body weight
than men. Alcohol does not go into fat cells as easily as other cells, so
more alcohol remains in the blood of women.
The more you weigh, the more water is present in your body. This water
dilutes the alcohol and lowers the BAC.
your stomach. Absorption will
be slowed if you’ve had something to eat.
What about other medications or drugs?
Medications or drugs will not
affect your BAC level. However, if you drink alcohol while taking certain
medications, you may feel – and be – more impaired, which can affect your
ability to perform driving-related tasks.
When am I impaired?
A: Because of the numerous factors that affect BAC,
it is very difficult to assess your own BAC or impairment. Though small amounts
of alcohol affect one’s brain and the ability to drive, people often swear they
are “fine” after several drinks – but in fact, the failure to recognize alcohol
impairment is often a symptom of impairment.
While the lower stages of alcohol impairment are undetectable to others, the
drinker knows vaguely when the “buzz” begins. A person will likely be too
impaired to drive before looking – or maybe even feeling – “drunk.”
How will I know I’m impaired, and why should I care?
Alcohol steadily decreases a
person’s ability to drive a motor vehicle safely. The more you drink, the
greater the effect. As with BAC, the signs of impairment differ with the
In single-vehicle crashes, the relative risk of a driver with BAC between .08
and .10 is at least 11 times greater than for drivers
with a BAC of zero, and 52 times greater for young males. Further, many
studies have shown that even small amounts of alcohol can impair a person’s
ability to drive.
Every State has passed a law making it illegal to drive with a BAC of .08 or
higher. A driver also can be arrested with a BAC below .08 when a law
enforcement officer has probable cause, based on the driver’s behavior.
The following chart contains some of the more common symptoms people exhibit at
various BAC levels, and the probable effects on driving ability:
What can I do to stay
safe when I plan on drinking?
If you plan on drinking, plan not
You should always:
Choose a non-drinking friend as a designated driver, or
Ask ahead of time if you can stay over at your host’s house, or
Take a taxi (your community may have a Safe Rides program for a free
ride home), and
wear your safety belt – it’s your best defense against impaired drivers