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. Also see
Traction Assist System
(TAS) on page 4-10.
Braking
Braking action involvesperception timeandreaction
time.
First, you have to decide to push on the brake pedal.
That'sperception time.Then you have to bring up your
foot and do it. That'sreaction time.
Averagereaction timeis 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.
4-6
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
®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, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
Supplemental Brake Assist System
If your vehicle has vacuum assist power brakes, it is also
equipped with a supplemental brake assist system
that supplies additional vacuum to the vacuum brake
booster if engine vacuum is reduced. Under certain
conditions, the supplemental brake assist system may
run brie¯y after starting your vehicle or when you
apply and release the brake pedal and it may continue
to run even after you have removed your foot from
the brake pedal. When the supplemental brake assistsystem is operating, you may hear a motor running or
feel a slight vibration in the steering wheel or brake
pedal. This indicates that the supplemental brake assist
system is working to supply additional vacuum for
your vacuum assist power brakes. This is a normal
operation of your brake system and does not require that
the brake system be serviced.
Each time you start your vehicle and accelerate to 10
mph, the supplemental brake assist system will perform
a self-diagnostic check of the system and you may
hear or feel the supplemental brake assist motor run
brie¯y. While you are driving your vehicle, the
supplemental brake assist system monitors itself to
ensure that it is operating properly. If there is a problem
with the supplemental brake assist system, the
SERVICE BRAKE BOOSTER message will be displayed
on the Driver Information Center. See
DIC Warnings
and Messages on page 3-57.
If your supplemental brake assist system runs every
time you apply and release the brake pedal or you notice
that the brake pedal has suddenly become much
harder to push and the vehicle takes longer to stop, you
should have your vehicle serviced as soon as possible.
4-9
of the transmission. When this happens you may notice
a reduction in acceleration, or may hear a noise or
vibration. This is normal.
If your vehicle is in cruise control when the system
activates, the STABILITY SYS ACTIVE message will
appear on the Driver Information Center and the cruise
control will automatically disengage. When road
conditions allow you to use cruise again, you may
re-engage the cruise control. See ªCruise Controlº under
Turn Signal/Multifunction Lever on page 3-7.
Stabilitrak
žmay also turn off automatically if it
determines that a problem exists with the system. If the
problem does not clear itself after restarting the
vehicle, you should see your dealer for service.
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.
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.
Suppose you're steering through a sharp curve. Then
you suddenly accelerate. Both control systems Ð
steering and acceleration Ð 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. See
Traction Assist System (TAS) on page 4-10.
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.
4-14
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 ®nd
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 Ð if you can stop
in time. But sometimes you can't; there isn't room.
That's the time for evasive action Ð steering around the
problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
See
Braking on page 4-6. 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.An emergency like this requires close attention and a
quick decision. If you are holding the steering wheel at
the recommended 9 and 3 o'clock positions, you
can turn it a full 180 degrees very quickly without
removing either hand. But you have to act fast, steer
quickly, and just as quickly straighten the wheel
once you have avoided the object.
The fact that such emergency situations are always
possible is a good reason to practice defensive driving
at all times and wear safety belts properly.
4-15
Off-Road Recovery
You may ®nd that your right wheels have dropped off
the edge of a road onto the shoulder while you're
driving.
If the level of the shoulder is only slightly below the
pavement, recovery should be fairly easy. Ease off the
accelerator and then, if there is nothing in the way,
steer so that your vehicle straddles the edge of
the pavement. You can turn the steering wheel up to
one-quarter turn until the right front tire contacts
the pavement edge. Then turn your steering wheel to go
straight down the roadway.
Passing
The driver of a vehicle about to pass another on a
two-lane highway waits for just the right moment,
accelerates, moves around the vehicle ahead, then
goes back into the right lane again. A simple maneuver?
Not necessarily! Passing another vehicle on a two-lane
highway is a potentially dangerous move, since the
passing vehicle occupies the same lane as oncoming
traffic for several seconds. A miscalculation, an error in
judgment, or a brief surrender to frustration or anger
can suddenly put the passing driver face to face with the
worst of all traffic accidents Ð the head-on collision.
So here are some tips for passing:
·ªDrive ahead.º Look down the road, to the sides
and to crossroads for situations that might affect
your passing patterns. If you have any doubt
whatsoever about making a successful pass, wait
for a better time.
·Watch for traffic signs, pavement markings and
lines. If you can see a sign up ahead that might
indicate a turn or an intersection, delay your pass.
A broken center line usually indicates it's all
right to pass (providing the road ahead is clear).
Never cross a solid line on your side of the lane or
a double solid line, even if the road seems empty
of approaching traffic.
4-16
Loss of Control
Let's review what driving experts say about what
happens when the three control systems (brakes,
steering and acceleration) don't have enough friction
where the tires meet the road to do what the driver has
asked.
In any emergency, don't 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
ªoverdrivingº 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
aren't 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.
A cornering skid is best handled by easing your foot off
the accelerator pedal.If you have the Traction Assist System, remember: It
helps avoid only the acceleration skid. If you do not have
this system, or if the 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'll
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 engine braking 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 Ð such as enough water, ice or packed snow
on the road to make a ªmirrored surfaceº Ð and slow
down when you have any doubt.
Remember: Any anti-lock brake system (ABS) helps
avoid only the braking skid.
4-18
Controlling your vehicle is the key to successful off-road
driving. One of the best ways to control your vehicle
is to control your speed. Here are some things to keep
in mind. At higher speeds:
·you approach things faster and you have less time
to scan the terrain for obstacles.
·you have less time to react.
·you have more vehicle bounce when you drive over
obstacles.
·you'll need more distance for braking, especially
since you're on an unpaved surface.
{CAUTION:
When you're driving off-road, bouncing and
quick changes in direction can easily throw
you out of position. This could cause you to
lose control and crash. So, whether you're
driving on or off the road, you and your
passengers should wear safety belts.
Scanning the Terrain
Off-road driving can take you over many different kinds
of terrain. You need to be familiar with the terrain
and its many different features. Here are some things to
consider.
Surface Conditions:Off-roading can take you over
hard-packed dirt, gravel, rocks, grass, sand, mud, snow
or ice. Each of these surfaces affects the steering,
acceleration and braking of your vehicle in different
ways. Depending upon the kind of surface you are on,
you may experience slipping, sliding, wheel spinning,
delayed acceleration, poor traction and longer braking
distances.
Surface Obstacles:Unseen or hidden obstacles can
be hazardous. A rock, log, hole, rut or bump can startle
you if you're not prepared for them. Often these
obstacles are hidden by grass, bushes, snow or even
the rise and fall of the terrain itself. Here are some
things to consider:
·Is the path ahead clear?
·Will the surface texture change abruptly up ahead?
·Does the travel take you uphill or downhill?
(There's more discussion of these subjects later.)
·Will you have to stop suddenly or change direction
quickly?
4-22
When you drive over obstacles or rough terrain, keep a
®rm grip on the steering wheel. Ruts, troughs or
other surface features can jerk the wheel out of your
hands if you're not prepared.
When you drive over bumps, rocks, or other obstacles,
your wheels can leave the ground. If this happens,
even with one or two wheels, you can't control
the vehicle as well or at all.
Because you will be on an unpaved surface, it's
especially important to avoid sudden acceleration,
sudden turns or sudden braking.
In a way, off-road driving requires a different kind of
alertness from driving on paved roads and highways.
There are no road signs, posted speed limits or
signal lights. You have to use your own good judgment
about what is safe and what isn't.
Drinking and driving can be very dangerous on any
road. And this is certainly true for off-road driving. At the
very time you need special alertness and driving
skills, your re¯exes, perceptions and judgment can be
affected by even a small amount of alcohol. You
could have a serious Ð or even fatal Ð accident if you
drink and drive or ride with a driver who has been
drinking. See
Drunken Driving on page 4-3.
Driving on Off-Road Hills
Off-road driving often takes you up, down or across a
hill. Driving safely on hills requires good judgment
and an understanding of what your vehicle can and can't
do. There are some hills that simply can't be driven,
no matter how well built the vehicle.
{CAUTION:
Many hills are simply too steep for any vehicle.
If you drive up them, you will stall. If you drive
down them, you can't control your speed. If
you drive across them, you will roll over. You
could be seriously injured or killed. If you have
any doubt about the steepness, don't drive the
hill.
4-23