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Drunken Driving
Death and injury associated with drinking and driving is
a national tragedy. It is the number one contributor
to the highway death toll, claiming thousands of victims
every year.
Alcohol affects four things that anyone needs to drive
a vehicle:
Judgment
Muscular Coordination
Vision
Attentiveness
Police records show that almost half of all motor
vehicle-related deaths involve alcohol. In most cases,
these deaths are the result of someone who was
drinking and driving. In recent years, more than
16,000 annual motor vehicle-related deaths have been
associated with the use of alcohol, with more than
300,000 people injured.Many adults — by some estimates, nearly half the adult
population — choose never to drink alcohol, so they
never drive after drinking. For persons under 21,
it is against the law in every U.S. state to drink alcohol.
There are good medical, psychological, and
developmental reasons for these laws.
The obvious way to eliminate the leading highway
safety problem is for people never to drink alcohol and
then drive. But what if people do? How much is “too
much” if someone plans to drive? It is a lot less
than many might think. Although it depends on each
person and situation, here is some general information
on the problem.
The Blood Alcohol Concentration (BAC) of someone
who is drinking depends upon four things:
The amount of alcohol consumed
The drinker’s body weight
The amount of food that is consumed before and
during drinking
The length of time it has taken the drinker to
consume the alcohol
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According to the American Medical Association, a 180 lb
(82 kg) person who drinks three 12 ounce (355 ml)
bottles of beer in an hour will end up with a BAC
of about 0.06 percent. The person would reach the
same BAC by drinking three 4 ounce (120 ml) glasses
of wine or three mixed drinks if each had 1-1/2 ounces
(45 ml) of liquors like whiskey, gin, or vodka.
It is 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’sBAC 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 most 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 have 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.
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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 will be careful” is not the
right answer. What if there is 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 is something else about drinking and driving that
many people do not 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.
{CAUTION:
Drinking and then driving is very dangerous.
Your re exes, perceptions, attentiveness, and
judgment can be affected by even a small
amount of alcohol. You can have a serious — or
even fatal — collision if you drive after drinking.
Please do not drink and drive or ride with a
driver who has been drinking. Ride home in a
cab; or if you are with a group, designate a
driver who will not drink.
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Control of a Vehicle
You have three systems that make your vehicle go
where you want it to go. They are the brakes, the
steering, and the accelerator. All three systems have
to do their work at the places where the tires meet
the road.
Sometimes, as when you are driving on snow or ice, it
is easy to ask more of those control systems than
the tires and road can provide. That means you can lose
control of your vehicle.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3.
Braking
SeeBrake System Warning Light on page 3-32.
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake pedal.
That is perception time. Then you have to bring up your
foot and do it. That is reaction time.
Average reaction time is about three-fourths of a
second. But that is only an average. It might be less
with one driver and as long as two or three seconds or
more with another. Age, physical condition, alertness,
coordination, and eyesight all play a part. So do alcohol,
drugs, and frustration. But even in three-fourths of a
second, a vehicle moving at 60 mph (100 km/h) travels
66 feet (20 m). That could be a lot of distance in an
emergency, so keeping enough space between
your vehicle and others is important.
And, of course, actual stopping distances vary greatly
with the surface of the road, whether it is pavement
or gravel; the condition of the road, whether it is
wet, dry, or icy; tire tread; the condition of your brakes;
the weight of the vehicle; and the amount of brake
force applied.
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Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic. This is a
mistake. Your brakes may not have time to cool between
hard stops. Your brakes will wear out much faster if you
do a lot of heavy braking. If you keep pace with the traffic
and allow realistic following distances, you will eliminate a
lot of unnecessary braking. That means better braking
and longer brake life.
If your engine ever stops while you are driving, brake
normally but do not pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3.Anti-Lock Brake System (ABS)
Your vehicle may have the Anti-Lock Brake
System (ABS), an advanced electronic braking
system that will help prevent a braking skid.
If your vehicle has ABS, this warning light on the
instrument panel will come on brie y when you start
your vehicle.
When you start your engine, or when you begin to drive
away, ABS will check itself. You may hear a momentary
motor or clicking noise while this test is going on,
and you may even notice that your brake pedal moves
or pulses a little. This is normal.
If there is a problem with ABS, the anti-lock brake
system warning light will stay on. SeeAnti-Lock Brake
System Warning Light on page 3-33. United States
Canada
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Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:
A computer senses that wheels are slowing down. If
one of the wheels is about to stop rolling, the computer
will separately work the brakes at each front wheel
and at both rear wheels.
ABS can change the brake pressure faster than any
driver could. The computer is programmed to make the
most of available tire and road conditions. This can
help you steer around the obstacle while braking hard.As you brake, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
If your vehicle has the vehicle stability control system, it
includes a brake assist system which provides more
powerful braking during a sudden, hard brake
application. See “Vehicle Stability Control System”
underTraction Control System (TCS) on page 4-9.
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Remember: ABS does not change the time you need to
get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle
in front of you, you will not have time to apply your
brakes if that vehicle suddenly slows or stops. Always
leave enough room up ahead to stop, even though
you have ABS.
Using ABS
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
a slight brake pedal pulsation or notice some noise,
but this is normal.
Braking in Emergencies
At some time, nearly every driver gets into a situation
that requires hard braking.
If you have ABS, you can steer and brake at the same
time. However, if you do not have ABS, your rst
reaction — to hit the brake pedal hard and hold it
down — may be the wrong thing to do. Your wheels can
stop rolling. Once they do, the vehicle cannot respond
to your steering. Momentum will carry it in whatever
direction it was headed when the wheels stopped rolling.
That could be off the road, into the very thing you
were trying to avoid, or into traffic.If you do not have ABS, use a “squeeze” braking
technique. This will give you maximum braking while
maintaining steering control. You can do this by pushing
on the brake pedal with steadily increasing pressure.
In an emergency, you will probably want to squeeze the
brakes hard without locking the wheels. If you hear or feel
the wheels sliding, ease off the brake pedal. This will help
you retain steering control. If you do have ABS, it is
different. SeeAnti-Lock Brake System (ABS) on
page 4-7.
In many emergencies, steering can help you more than
even the very best braking.
Traction Control System (TCS)
Your vehicle may have a traction control system that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only if it senses
that one or both of the front wheels are spinning or
beginning to lose traction. When this happens,
the system works the front brakes and reduces engine
power to limit wheel spin.
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You may feel or hear the system working, but this is
normal. Leave the system on during ordinary driving so
that it can operate when needed. When the ignition
is turned to ON, the system automatically turns on.
This light should come on
brie y when you start the
engine. If it stays on or
comes on while you
are driving, there is a
problem with your traction
control system.
The TRAC OFF button is
located to the left of the
steering wheel below
the instrument panel
cluster.When getting the vehicle out of mud or newly fallen
snow, turn off the traction control system. The system
that controls engine performance interferes with the
process of freeing the front wheels. To turn off traction
control, press the TRAC OFF button. The traction
control system warning light will come on. The vehicle
stability control system (StabiliTrak
®) is always activated,
even when the traction control system is turned off.
To turn the traction control system back on, press the
TRAC OFF button again. The traction control system
warning light will go off. SeeTraction Control System
(TCS) Warning Light on page 3-34for more information.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3for more information.
StabiliTrak®System
Your vehicle may have this feature. The StabiliTrak®
system helps provide integrated control of the systems
such as anti-lock brake system, traction control and
engine control. This system automatically controls the
brakes and engine to help prevent the vehicle from
skidding when cornering on a slippery road surface or
turning the steering wheel abruptly.
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