The Commercial Drivers License
EMERGENCIES
Traffic emergencies occur when two vehicles are about to collide.
Vehicle emergencies occur when tires, brakes or other critical
parts fail.
Following the safety practices in this manual can help prevent
emergencies. But if an emergency does happen, your chances of avoiding
an accident depend upon how well you take action. Actions you can
take are discussed below.
Steering to Avoid a Crash Stopping is not always the safest thing
to do in an emergency. When you don’t have enough room to stop,
you may have to steer away from what’s ahead. Remember, you can
almost always turn to miss an obstacle more quickly than you can
stop. (However, top-heavy vehicles and tractors with multiple trailers
may flip over.)
Keep Both Hands on the Steering Wheel.
In order to turn quickly, you must have a firm grip on the steering
wheel with both hands. The best way to have both hands on the wheel
if there is an emergency is to keep them there all the time.
How to Turn Quickly and Safely.
A quick turn can be made safely, if it’s done the right way. Here
are some points that safe drivers use:
• Do not apply the brake while you are turning. It’s very easy
to lock your wheels while turning. If that happens, you may skid
out of control.
• Do not turn any more than needed to clear whatever is in your
way. The more sharply you turn, the greater the chances of a skid
or rollover.
• Be prepared to “countersteer,” that is, to turn the wheel back
in the other direction, once you’ve passed whatever was in your
path. Unless you are prepared to countersteer, you won’t be able
to do it quickly enough.
You should think of emergency steering and countersteering as two
parts of one driving action. Where to Steer. If an oncoming driver
has drifted into your lane, a move to your right is best. If that
driver realizes what has happened, the natural response will be
to return to his or her own lane. If something is blocking your
path, the best direction to steer will depend on the situation.
• If you have been using your mirrors, you’ll know which lane is
empty and can be safely used.
• If the shoulder is clear, going right may be best. No
one is likely to be driving on the shoulder but someone may be passing
you on the left. You will know if you have been using your
mirrors. Shoulder driving is not legal unless posted to do so. This
evasive action should be used in emergency situations only.
• If you are blocked on both sides, a move to the right may be
best. At least you won’t force anyone into an opposing traffic lane
and a possible head-on collision. Leaving the Road. In some emergencies,
you may have to drive off the road. It may be less risky than facing
a collision with another vehicle. Most shoulders are strong enough
to support the weight of a large vehicle and, therefore, offer an
available escape route. Here are some guidelines, if you do leave
the road.
Avoid Braking.
If possible, avoid using the brakes until
your speed has dropped to about 20 mph. Then brake very gently to
avoid skidding on a loose surface. Keep one set of wheels on pavement
if possible. This helps to maintain control.
Stay on the Shoulder.
If the shoulder is clear, stay on it until your vehicle has come
to a stop. Signal and check your mirrors before pulling back onto
the road. Returning to the Road. If you are forced to return to
the road before you can stop, use the following procedure:
• Hold the wheel tightly and turn sharply enough to get right back
on the road safely. Don’t try to edge gradually back on the road.
If you do, your tires might grab unexpectedly and you could lose
control.
• When both front tires are on the paved surface, countersteer
immediately. The two turns should be made as a single “steer-countersteer”
move.
How to Stop Quickly and Safely
If somebody suddenly pulls out in front of you, your natural response
is to hit the brakes. This is a good response if there’s enough
distance to stop and you use the brakes correctly. You should brake
in a way that will keep your vehicle in a straight line and allow
you to turn if it becomes necessary. You can use the “controlled
braking” method or the “stab braking” method.
Controlled braking. With this method, you apply the brakes as hard
as you can without locking the wheels. Keep steering wheel movements
very small while doing this. If you need to make a larger steering
adjustment or if the wheels lock, release the brakes. Reapply the
brakes as soon as you can.
Stab braking:
• Apply your brakes all the way.
• Release brakes when wheels lock up.
• As soon as the wheels start rolling, apply the brakes fully again.
(It can take up to one second for the wheels to start rolling after
you release the brakes. If you reapply the brakes before the wheels
start rolling, the vehicle won’t straighten out.) Don’t Jam on the
Brakes. Emergency braking does not mean pushing down on the brake
pedal as hard as you can. That will only keep the wheels locked
up and cause a skid. If the wheels are skidding, you cannot control
the vehicle.
Brake Failure
Brakes kept in good condition rarely fail. Most hydraulic brake
failures occur for one of two reasons: (Air brakes are discussed
in Section 5.)
• Loss of hydraulic pressure
• Brake fade on long hills. Loss of Hydraulic Pressure. When the
system won’t build up pressure, the brake pedal will feel spongy
or go to the floor. Here are some things you can do:
• Downshift. Putting the vehicle into a lower gear will help to
slow the vehicle.
• Pump the brakes. Sometimes pumping the brake pedal will generate
enough hydraulic pressure to stop the vehicle.
• Use the parking brake. The parking or emergency brake is separate
from the hydraulic brake system. Therefore, it can be used to slow
the vehicle. However, be sure to press the release button or pull
the release lever at the same time you use the emergency brake so
you can adjust the brake pressure and keep the wheels from locking
up.
• Find an escape route.
While slowing the vehicle, look for an escape route—an open field,
side street or escape ramp. Turning uphill is a good way to slow
and stop the vehicle. Make sure the vehicle does not start rolling
backward after you stop. Put it in low gear, apply the parking brake
and if necessary roll back into some obstacle that will stop the
vehicle.
Brake Failure on Downgrades.
Going slow enough and braking properly will almost always prevent
brake failure on long downgrades. Once the brakes have failed, however,
you are going to have to look outside your vehicle for something
to stop it. Your best hope is an escape ramp. If there is one, there’ll
be signs telling you about it. Use it. Ramps
are usually located a few miles from the top of the downgrade.
Every year, hundreds of drivers avoid injury to themselves or damage
to their vehicles by using escape ramps. Some escape ramps use soft
gravel that resists the motion of the vehicle and brings it to a
stop. Others turn uphill, using the hill to stop the vehicle and
soft gravel to hold it in place. Any driver who loses brakes going
downhill should use an escape ramp if it’s available. If you don’t
use it, your chances of having a serious accident may be much worse.
If no escape ramp is available, take the least hazardous escape
route you can — such as an open field, or a side road that flattens
outor turns uphill. Make the move as soon as you know your brakes
don’t work. The longer you wait, the faster the vehicle will go
and the harder it will be to stop.
Tire Failure
There are four important things that safe
drivers do to handle a tire failure safely
• Be aware that a tire has failed.
• Hold the steering wheel firmly.
• Stay off the brake.
• After stopping, check all the tires.
Recognize Tire Failure. Quickly knowing you have a tire failure
will let you have more time to react. Having just a few seconds
to remember what it is you’re supposed to do can help you. The major
signs of tire failure are:
• Sound. The loud “bang” of a blowout is an easily recognized sign.
Because it can take a few seconds for your vehicle to react, you
might think it was some other vehicle. But any time you hear a tire
blow, you’d be safest to assume it was yours.
• Vibration. If the vehicle thumps or vibrates heavily, it may
be a sign that one of the tires has gone flat. With a rear tire,
that may be the only sign you get.
• Feel. If the steering feels “heavy,” it is probably a sign that
one of the front tires has failed. Sometimes, failure of a rear
tire will cause the vehicle to slide back and forth or “fishtail.”
However, dual rear tires usually prevent this. Any of these signs
is a warning of possible tire failure. You should do the following
things.
• Hold the Steering Wheel Firmly. If a front tire fails, it can
twist the steering wheel out of your hand. The only way to prevent
this is to keep a firm grip on the steering wheel with both hands
at all times.
• Stay Off the Brake. It’s natural
to want to brake in an emergency. However, braking when a tire has
failed could cause loss of control. Unless you’re about to run into
something, stay off the brake until the vehicle has slowed down.
Then brake very gently, pull off the road, and stop.
• Check the Tires. After you’ve come to a stop, get out and check
all the tires. Do this even if the vehicle seems to be handling
all right. If one of your dual tires goes, the only way you may
know it is by getting out and looking at it.
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