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.
Braking
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 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 (1 00 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; and the condition of your brakes.
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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
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,
ANTI -
LOCK
If there’s a problem with the
anti-lock brake system, this
warning light will stay on.
See “Anti-Lock Brake
System Warning Light” 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 the
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 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
Use your anti-lock braking system when you need to.
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,
Steering Tips
Driving on Curves
It’s important to take curves at a reasonable speed.
A lot of the “driver lost control’’ 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 -- 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.
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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 “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.
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 “Braking
in
Emergencies’’ 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. 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.
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0 Do not get too close to the vehicle you want to
pass while you’re awaiting an opportunity. For one
thing, following
too closely reduces your area of
vision, especially if you’re following a larger
vehicle. Also,
you won’t have adequate space if
the vehicle ahead suddenly slows or stops. Keep
back a reasonable distance.
0 When it looks like a chance to pass is coming up,
start to accelerate but stay
in the right lane and don’t
get too close. Time your move
so you will be
increasing speed as
the time comes to move into the
other lane. If the way is clear to pass, you will have a
“running start” that more than makes up for
the
distance you would lose by dropping back. And if
something happens
to cause you to cancel your pass,
you need
only slow down and drop back again and
wait for another opportunity.
If other cars are lined up to pass a slow vehicle, wait
your turn. But take care that someone
isn’t trying to
pass you as you pull out to pass the slow vehicle.
Remember
to glance over your shoulder and check
the blind spot.
Check your 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
inside mirror, activate your right lane change signal
and move back
into,the right lane. (Remember that
your right outside mirror is convex. The vehicle you
just passed may seem to be farther away from
you
than it really is.)
0 Try not to pass more than one vehicle at a time
on two-lane roads. Reconsider before passing the
next vehicle.
0 Don’t overtake a slowly moving vehicle too rapidly.
Even though
the brake lamps are not flashing, it may
be slowing down or starting to turn.
0 If you’re being passed, make it easy for the
following driver to get ahead of you. Perhaps you
can ease a little to the right.
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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 “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
aren’t rolling. In
the steering or cornering skid, too
muchspeed 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 and an acceleration skid are 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
--
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.
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The heavier the rain, the harder it is to see. Even if your
windshield wiper blades are
in good shape, a heavy rain
can make
it harder to see road signs and traffic signals,
pavement markings,
the edge of the road and even
people walking.
It’s wise to keep
your wiping equipment in good shape
and keep your windshield washer tank filled
with
washer fluid. Replace your windshield wiper inserts
when they show signs
of streaking or missing areas on
the windshield, or when strips of rubber start to separate
from the inserts. Driving too fast through large water puddles
or
even
going through some car washes can cause problems, too.
The water may affect your brakes. Try to avoid puddles.
But if you can’t, try to slow down before you hit them.
Wet brakes can cause accidents. They won’t work
well in a quick stop and may cause pulling to one
side.
You could lose control of the vehicle.
After driving through a large puddle of water or
a car wash, apply your brake pedal lightly until
your brakes work normally.
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