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) (CTS) on page 293or
Traction Control System (TCS) (CTS-V) on
page 295.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modi cations on page 332.
Braking
SeeBrake System Warning Light on page 205.
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 the brakes; the weight of the vehicle;
and the amount of brake force applied.
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Steering Tips
It is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents
mentioned on the news happen on curves.
Here is 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 is no traction, inertia will keep the vehicle
going in the same direction. If you have ever
tried to steer a vehicle on wet ice, you will
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 are in a curve, speed is the
one factor you can control.
Suppose you are 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.
SeeTraction Control System (TCS) (CTS) on
page 293orTraction Control System (TCS)
(CTS-V) on page 295.
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 will 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 “drive” 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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modi cations on page 332.
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Check your vehicle’s mirrors, glance over your
shoulder, and start your left lane change
signal before moving out of the right lane to
pass. When you are far enough ahead of
the passed vehicle to see its front in
your vehicle’s inside mirror, activate the right
lane change signal and move back into
the right lane. Remember that your vehicle’s
passenger side outside mirror is convex.
The vehicle you just passed may seem to be
farther away from you than it really is.
Try not to pass more than one vehicle at a
time on two-lane roads. Reconsider before
passing the next vehicle.
Do not overtake a slowly moving vehicle too
rapidly. Even though the brake lamps are
not ashing, it may be slowing down or starting
to turn.
If you are being passed, make it easy for the
following driver to get ahead of you. Perhaps
you can ease a little to the right.
Loss of Control
Let us review what driving experts say about what
happens when the three control systems — brakes,
steering, and acceleration — do not have enough
friction where the tires meet the road to do what the
driver has asked.
In any emergency, do not give up. Keep trying to
steer and constantly seek an escape route or
area of less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking
reasonable care suited to existing conditions, and
by not overdriving those conditions. But skids
are always possible.
The three types of skids correspond to your
vehicle’s three control systems. In the braking skid,
your wheels are not rolling. In the steering or
cornering skid, too much speed or steering in a
curve causes tires to slip and lose cornering force.
And in the acceleration skid, too much throttle
causes the driving wheels to spin.
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A cornering skid is best handled by easing your
foot off the accelerator pedal.
Remember: Any traction control system helps
avoid only the acceleration skid. If your traction
control system is off, then an acceleration skid is
also best handled by easing your foot off the
accelerator pedal.
If your vehicle starts to slide, ease your foot off
the accelerator pedal and quickly steer the
way you want the vehicle to go. If you start
steering quickly enough, your vehicle may
straighten out. Always be ready for a second skid
if it occurs.
Of course, traction is reduced when water, snow,
ice, gravel, or other material is on the road.
For safety, you will want to slow down and adjust
your driving to these conditions. It is important
to slow down on slippery surfaces because
stopping distance will be longer and vehicle control
more limited.
While driving on a surface with reduced traction,
try your best to avoid sudden steering,
acceleration, or braking, including reducing
vehicle speed by shifting to a lower gear.Any sudden changes could cause the tires to
slide. You may not realize the surface is slippery
until your vehicle is skidding. Learn to recognize
warning clues — such as enough water, ice,
or packed snow on the road to make a mirrored
surface — and slow down when you have
any doubt.
Remember: Any Anti-Lock Brake System (ABS)
helps avoid only the braking skid.
Competitive Driving
See your warranty book before using your vehicle
for competitive driving.
Notice:If you use your vehicle for competitive
driving, the engine may use more oil than it
would with normal use. Low oil levels can
damage the engine. Be sure to check the oil
level often during competitive driving and keep
the level at or near the upper mark that
shows the proper operating range on the
engine oil dipstick. For information on how to
add oil, seeEngine Oil on page 346.
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