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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.
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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 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.
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. SeeTraction Control System
(TCS) on page 4-9.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3.
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Braking
SeeBrake System Warning Light on page 3-35.
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.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.
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Anti-Lock Brake System (ABS)
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test is going on. This is normal.
If there is a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-36.
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.
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The anti-lock system 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.Remember: Anti-lock 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 anti-lock brakes.
Using Anti-Lock
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise,
but this is normal.
Braking in Emergencies
With anti-lock brakes, you can steer and brake at the
same time. In many emergencies, steering can help you
more than even the very best braking.
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Traction Control System (TCS)
Your vehicle has a Traction Control System (TCS) that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only if it senses
that any of the wheels are spinning or beginning to lose
traction. When this happens, the system applies the
brakes to limit wheel spin.
The Traction Control System may operate on dry roads
under some conditions. When this happens, you may
notice a reduction in acceleration or a pumping sound.
This is normal and doesn’t mean there’s a problem with
your vehicle. Examples of these conditions include hard
acceleration in a turn, an abrupt upshift or downshift of
the transmission or driving on rough roads.
If your vehicle is in cruise control when the TCS begins
to limit wheel spin, the cruise control will automatically
disengage. When road conditions allow you to safely
use it again, you may re-engage the cruise control. See
Cruise Control on page 3-11.
Another feature of this system is the Traction
Control 2 (TC2) mode. TC2 should be selected for
improved traction and system performance when the
vehicle is on loose surfaces such as deep sand or mud.To enter this mode,
press the TC2 button
located on the instrument
panel to the right of
the steering wheel.
TC2 only operates in the following transfer case modes:
Four-Wheel-High Lock
Four-Wheel-Low Lock
Four-Wheel-Low Lock and Rear Axle Lock
SeeLocking Rear Axle on page 4-10for more
information on the rear axle lock.
It will not operate in Four-Wheel-High. If the TC2 button
is pressed while in Four-Wheel High, the light will
ash for about 15 seconds and then go out. The light
should also come on brie y when you turn the ignition
key to RUN; if it doesn’t see your dealer for service.
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If you restart your engine, the system reverts to the
standard TCS mode.
The traction off light will
come on when a Traction
Control System or
Anti-Lock Brake System
problem has been detected
and the vehicle needs
service.
SeeTraction Off Light on page 3-36.
When the traction off light is on, adjust your driving
accordingly.
The traction control system, as delivered from the
factory, will automatically come on whenever you start
your vehicle.
Adding non-GM accessories can affect your vehicle’s
performance. SeeAccessories and Modi cations
on page 5-3for more information.Locking Rear Axle
The locking rear axle can give your vehicle additional
traction from the rear wheels when traveling in off-road
situations such as mud, snow, sand, steep hills and
uneven terrain.
The button used to turn
this feature on or off is
located above the transfer
case buttons to the
right of the steering wheel.
To lock the rear axle, do the following:
1. Place the transfer case in the Four-Wheel-Low Lock
mode. This is the only mode which will allow the rear
axle to lock. SeeFull-Time Four-Wheel Drive on
page 2-30for more information regarding the transfer
case and Four-Wheel-Low-Lock mode.
2. Press the button with the vehicle stopped or moving
less than 2 mph (3 km/h).
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