It’s the amount of alcohol that counts. For example, if
the same person drank three double martinis (3 ounces
or 90 ml of liquor each) within an hour, the person’s
BAC would be close to 0.12 percent. A person
who consumes food just before or during drinking will
have a somewhat lower BAC level.
There is a gender difference, too. Women generally
have a lower relative percentage of body water
than men. Since alcohol is carried in body water, this
means that a woman generally will reach a higher BAC
level than a man of her same body weight will when
each has the same number of drinks.
The law in an increasing number of U.S. states, and
throughout Canada, sets the legal limit at 0.08 percent.
In some other countries, the limit is even lower. For
example, it is 0.05 percent in both France and Germany.
The BAC limit for all commercial drivers in the United
States is 0.04 percent.
The BAC will be over 0.10 percent after three to six
drinks (in one hour). Of course, as we’ve seen, it
depends on how much alcohol is in the drinks, and how
quickly the person drinks them.
But the ability to drive is affected well below a BAC of
0.10 percent. Research shows that the driving skills
of many people are impaired at a BAC approaching
0.05 percent, and that the effects are worse at night.
All drivers are impaired at BAC levels above
0.05 percent. Statistics show that the chance of being in
a collision increases sharply for drivers who have a
BAC of 0.05 percent or above. A driver with a BAC level
of 0.06 percent has doubled his or her chance of
having a collision. At a BAC level of 0.10 percent, the
chance of this driver having a collision is 12 times
greater; at a level of 0.15 percent, the chance is
25 times greater!
The body takes about an hour to rid itself of the alcohol
in one drink. No amount of coffee or number of cold
showers will speed that up. “I’ll be careful” isn’t the right
answer. What if there’s an emergency, a need to
take sudden action, as when a child darts into the
street? A person with even a moderate BAC might not
be able to react quickly enough to avoid the collision.
There’s something else about drinking and driving that
many people don’t know. Medical research shows
that alcohol in a person’s system can make crash
injuries worse, especially injuries to the brain, spinal
cord or heart. This means that when anyone who
has been drinking — driver or passenger — is in a
crash, that person’s chance of being killed or
permanently disabled is higher than if the person had
not been drinking.
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