GMC YUKON 1999 Owner's Manual

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Section 4 Your Driving and the Road
Here you'll find information about driving on different kinds of roads and in varying weather conditions. We've also
included many other useful tips on driving.
4
-2 Defensive Driving
4
-3 Drunken Driving
4
-6 Control of a Vehicle
4
-6 Braking
4
-9 Steering
4
-11 Off-Road Recovery
4
-12 Passing
4
-13 Loss of Control
4
-14 Off-Road Driving with Your
Four
-Wheel-Drive Vehicle
4
-28 Driving at Night4
-30 Driving in Rain and on Wet Roads
4
-33 City Driving
4
-34 Freeway Driving
4
-35 Before Leaving on a Long Trip
4
-36 Highway Hypnosis
4
-36 Hill and Mountain Roads
4
-38 Winter Driving
4
-42 Recreational Vehicle Towing
4
-43 Loading Your Vehicle
4
-45 Towing a Trailer

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Defensive Driving
The best advice anyone can give about driving is:
Drive defensively.
Please start with a very important safety device in your
vehicle: Buckle up. (See ªSafety Beltsº in the Index.)Defensive driving really means ªbe ready for anything.º
On city streets, rural roads or freeways, it means
ªalways expect the unexpected.º
Assume that pedestrians or other drivers are going to be
careless and make mistakes. Anticipate what they might
do. Be ready for their mistakes.
Rear
-end collisions are about the most preventable of
accidents. Yet they are common. Allow enough
following distance. It's the best defensive driving
maneuver, in both city and rural driving. You never
know when the vehicle in front of you is going to brake
or turn suddenly.
Defensive driving requires that a driver concentrate on
the driving task. Anything that distracts from the driving
task
-- such as concentrating on a cellular telephone
call, reading, or reaching for something on the
floor
-- makes proper defensive driving more difficult
and can even cause a collision, with resulting injury.
Ask a passenger to help do things like this, or pull off
the road in a safe place to do them yourself. These
simple defensive driving techniques could save
your life.

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Drunken Driving
Death and injury associated with drinking and driving is
a national tragedy. It's 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, over 17,000 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's 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 solve the leading highway safety
problem is for people never to drink alcohol and then
drive. But what if people do? How much is ªtoo muchº
if the driver plans to drive? It's 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.
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 a liquor like whiskey, gin or vodka.

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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 when each has the same
number of drinks.
The law in many U.S. states sets the legal limit at a BAC
of 0.10 percent. In a growing number of U.S. states, and
throughout Canada, the limit is 0.08 percent. In some
other countries, it's even lower. 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!

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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. ªI'll be carefulº 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.
CAUTION:
Drinking and then driving is very dangerous.
Your reflexes, 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 don't drink and drive or ride with a driver
who has been drinking. Ride home in a cab; or if
you're 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're driving on snow or ice, it's
easy to ask more of those control systems than the tires
and road can provide. That means you can lose control
of your vehicle.
Braking
Braking action involves perception time and
reaction time.
First, you have to decide to push on the brake pedal.
That's perception time. Then you have to bring up your
foot and do it. That's reaction time.
Average reaction time is about 3/4 of a second. But
that's 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 3/4 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's pavement or
gravel); the condition of the road (wet, dry, 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're driving, brake
normally but don't 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.
Anti-Lock Brakes (ABS)
Your vehicle has anti-lock brakes (ABS). 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's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.

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Here's how anti-lock works. Let's say the road is wet.
You're driving safely. Suddenly an animal jumps out in
front of you.
You slam on the brakes. Here's 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.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.
You can steer around the obstacle while braking hard.
As you brake, your computer keeps receiving updates on
wheel speed and controls braking pressure accordingly.

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Remember: Anti-lock doesn't 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 won't 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
Don't pump the brakes. Just hold the brake pedal down
firmly and let anti
-lock work for you. You may feel the
brakes vibrate, or you may notice some noise, but
this is normal. Your anti
-lock brakes work at all
times
-- whether you are in two-wheel drive or
four
-wheel drive.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
Speed-Sensitive Steering
This system varies the amount of steering effort
proportionate to your vehicle speed. Steering is easier at
lower speeds for maneuvering and parking ease. As your
vehicle speed increases, the steering effort also
increases. At highway speeds, the amount of steering
effort is increased for vehicle control and stability.
Steering Tips
Driving on Curves
It's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº accidents mentioned on
the news happen on curves. Here's why:
Experienced driver or beginner, each of us is subject to
the same laws of physics when driving on curves. The
traction of the tires against the road surface makes it
possible for the vehicle to change its path when you turn
the front wheels. If there's no traction, inertia will keep
the vehicle going in the same direction. If you've ever
tried to steer a vehicle on wet ice, you'll understand this.
The traction you can get in a curve depends on the
condition of your tires and the road surface, the angle at
which the curve is banked, and your speed. While you're
in a curve, speed is the one factor you can control.

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Suppose you're steering through a sharp curve. Then you
suddenly accelerate. Both control systems
-- steering and
acceleration
-- have to do their work where the tires meet
the road. Adding the sudden acceleration can demand too
much of those places. You can lose control.
What should you do if this ever happens? Ease up on the
accelerator pedal, steer the vehicle the way you want it
to go, and slow down.
Speed limit signs near curves warn that you should
adjust your speed. Of course, the posted speeds are
based on good weather and road conditions. Under less
favorable conditions you'll want to go slower.
If you need to reduce your speed as you approach a
curve, do it before you enter the curve, while your front
wheels are straight ahead.
Try to adjust your speed so you can ªdriveº through the
curve. Maintain a reasonable, steady speed. Wait to
accelerate until you are out of the curve, and then
accelerate gently into the straightaway.
Steering in Emergencies
There are times when steering can be more effective than
braking. For example, you come over a hill and find a truck
stopped in your lane, or a car suddenly pulls out from
nowhere, or a child darts out from between parked cars and
stops right in front of you. You can avoid these problems by
braking
-- if you can stop in time. But sometimes you
can't; there isn't room. That's the time for evasive
action
-- steering around the problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes. (See ªBraking in
Emergenciesº earlier in this section.) It is better to
remove as much speed as you can from a possible
collision. Then steer around the problem, to the left or
right depending on the space available.