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Because these devices can be noisy, be sure you
know where their use is permitted.
Caution. When your drive wheels have poor
traction, the retarder may cause them to skid.
Therefore, you should turn the retarder off
whenever the road is wet, icy, or snow covered.
Subsections 2.2 and 2.3
Test Your Knowledge
1. Why should you back toward the driver's
side?
2. If stopped on a hill, how can you start
moving without rolling back?
3. When backing, why is it important to use a
helper?
4. What's the most important hand signal that
you and the helper should agree on?
5. What are the two special conditions where
you should downshift?
6. When should you downshift automatic
transmissions?
7. Retarders keep you from skidding when the
road is slippery. True or False?
8. What are the two ways to know when to
shift?
These questions may be on the test. If you can't
answer them all, re-read subsections 2.2 and 2.3.
2.4 – Seeing
To be a safe driver you need to know what's going
on all around your vehicle. Not looking properly is a
major cause of accidents.
2.4.1 – Seeing Ahead
All drivers look ahead; but many don't look far
enough ahead.
Importance of Looking Far Enough Ahead.
Because stopping or changing lanes can take a lot
of distance, knowing what the traffic is doing on all
sides of you is very important. You need to look well
ahead to make sure you have room to make these
moves safely.
How Far Ahead to Look. Most good drivers look at
least 12 to 15 seconds ahead. That means looking
ahead the distance you will travel in 12 to 15
seconds. At lower speeds, that's about one block.
At highway speeds it's about a quarter of a mile. If
you're not looking that far ahead, you may have to
stop too quickly or make quick lane changes.
Looking 12 to 15 seconds ahead doesn't mean not
paying attention to things that are closer. Good
drivers shift their attention back and forth, near and
far. Figure 2.6 illustrates how far to look ahead.
Figure 2.6
Look for Traffic. Look for vehicles coming onto the
highway, into your lane, or turning. Watch for brake
lights from slowing vehicles. By seeing these things
far enough ahead, you can change your speed, or
change lanes if necessary to avoid a problem. If a
traffic light has been green for a long time it will
probably change before you get there. Start slowing
down and be ready to stop.
2.4.2 – Seeing to the Sides and Rear
It's important to know what's going on behind and to
the sides. Check your mirrors regularly. Check more
often in special situations.
Mirror Adjustment. Mirror adjustment should be
checked prior to the start of any trip and can only be
checked accurately when the trailer(s) are straight.
You should check and adjust each mirror to show
some part of the vehicle. This will give you a
reference point for judging the position of the other
images.
Regular Checks. You need to make regular checks
of your mirrors to be aware of traffic and to check
your vehicle.
Traffic. Check your mirrors for vehicles on either
side and in back of you. In an emergency, you may
need to know whether you can make a quick lane
change. Use your mirrors to spot overtaking
vehicles. There are "blind spots" that your mirrors
cannot show you. Check your mirrors regularly to
know where other vehicles are around you, and to
see if they move into your blind spots.
Check Your Vehicle. Use the mirrors to keep an
eye on your tires. It's one way to spot a tire fire. If
you're carrying open cargo, you can use the mirrors
to check it. Look for loose straps, ropes, or chains.
Watch for a flapping or ballooning tarp.
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Special Situations. Special situations require more
than regular mirror checks. These are lane
changes, turns, merges, and tight maneuvers.
Lane Changes. You need to check your mirrors to
make sure no one is alongside you or about to pass
you. Check your mirrors:
Before you change lanes to make sure there is
enough room.
After you have signaled, to check that no one has
moved into your blind spot.
Right after you start the lane change, to double-
check that your path is clear.
After you complete the lane change.
Turns. In turns, check your mirrors to make sure the
rear of your vehicle will not hit anything.
Merges. When merging, use your mirrors to make
sure the gap in traffic is large enough for you to
enter safely.
Tight Maneuvers. Any time you are driving in close
quarters, check your mirrors often. Make sure you
have enough clearance.
How to Use Mirrors. Use mirrors correctly by
checking them quickly and understanding what you
see.
When you use your mirrors while driving on the
road, check quickly. Look back and forth between
the mirrors and the road ahead. Don't focus on the
mirrors for too long. Otherwise, you will travel quite
a distance without knowing what's happening
ahead.
Many large vehicles have curved (convex,
"fisheye," "spot," "bug-eye") mirrors that show a
wider area than flat mirrors. This is often helpful.
But everything appears smaller in a convex mirror
than it would if you were looking at it directly.
Things also seem farther away than they really are.
It's important to realize this and to allow for it.
Figure 2.7 shows the field of vision using a convex
mirror.
2.5 – Communicating
2.5.1 – Signal Your Intentions
Other drivers can't know what you are going to do
until you tell them.
Signaling what you intend to do is important for
safety. Here are some general rules for signaling.
Figure 2.7
Turns. There are three good rules for using turn
signals:
Signal early. Signal well before you turn. It is the
best way to keep others from trying to pass you.
Signal continuously. You need both hands on the
wheel to turn safely. Don't cancel the signal until
you have completed the turn.
Cancel your signal. Don't forget to turn off your turn
signal after you've turned (if you don't have self-
canceling signals).
Lane Changes. Put your turn signal on before
changing lanes. Change lanes slowly and smoothly.
That way a driver you didn't see may have a chance
to honk his/her horn, or avoid your vehicle.
Slowing Down. Warn drivers behind you when you
see you'll need to slow down. A few light taps on the
brake pedal -- enough to flash the brake lights --
should warn following drivers. Use the four-way
emergency flashers for times when you are driving
very slowly or are stopped. Warn other drivers in
any of the following situations:
Trouble Ahead. The size of your vehicle may
make it hard for drivers behind you to see hazards
ahead. If you see a hazard that will require slowing
down, warn the drivers behind by flashing your
brake lights.
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Tight Turns. Most car drivers don't know how
slowly you have to go to make a tight turn in a
large vehicle. Give drivers behind you warning by
braking early and slowing gradually.
Stopping on the Road. Truck and bus drivers
sometimes stop in the roadway to unload cargo or
passengers, or to stop at a railroad crossing. Warn
following drivers by flashing your brake lights.
Don't stop suddenly.
Driving Slowly. Drivers often do not realize how
fast they are catching up to a slow vehicle until
they are very close. If you must drive slowly, alert
following drivers by turning on your emergency
flashers if it is legal. (Laws regarding the use of
flashers differ from one state to another. Check the
laws of the states where you will drive.)
Don't Direct Traffic. Some drivers try to help out
others by signaling when it is safe to pass. You
should not do this. You could cause an accident.
You could be blamed and it could cost you many
thousands of dollars.
2.5.2 – Communicating Your Presence
Other drivers may not notice your vehicle even
when it's in plain sight. To help prevent accidents,
let them know you're there.
When Passing. Whenever you are about to pass a
vehicle, pedestrian, or bicyclist, assume they don't
see you. They could suddenly move in front of you.
When it is legal, tap the horn lightly or, at night, flash
your lights from low to high beam and back. And,
drive carefully enough to avoid a crash even if they
don't see or hear you.
When It's Hard to See. At dawn, dusk, in rain, or
snow, you need to make yourself easier to see. If
you are having trouble seeing other vehicles, other
drivers will have trouble seeing you. Turn on your
lights. Use the headlights, not just the identification
or clearance lights. Use the low beams; high beams
can bother people in the daytime as well as at night.
When Parked at the Side of the Road. When you
pull off the road and stop, be sure to turn on the four-
way emergency flashers. This is important at night.
Don't trust the taillights to give warning. Drivers
have crashed into the rear of a parked vehicle
because they thought it was moving normally.
If you must stop on a road or the shoulder of any
road, you must put out your emergency warning
devices within ten minutes. Place your warning
devices at the following locations:
If you must stop on or by a one-way or divided
highway, place warning devices 10 feet, 100 feet,
and 200 feet toward the approaching traffic. See
Figure 2.8.
Figure 2.8
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If you stop on a two-lane road carrying traffic in both
directions or on an undivided highway, place
warning devices within 10 feet of the front or rear
corners to mark the location of the vehicle and 100
feet behind and ahead of the vehicle, on the
shoulder or in the lane you stopped in. See Figure
2.9.
Figure 2.9
Back beyond any hill, curve, or other obstruction
that prevents other drivers from seeing the vehicle
within 500 feet. If line of sight view is obstructed due
to hill or curve, move the rear-most triangle to
a point back down the road so warning is provided.
See Figure 2.10.
Figure 2.10
When putting out the triangles, hold them between
yourself and the oncoming traffic for your own
safety. (So other drivers can see you.)
Use Your Horn When Needed. Your horn can let
others know you're there. It can help to avoid a
crash. Use your horn when needed. However, it can
startle others and could be dangerous when used
unnecessarily.
2.6 – Controlling Speed
Driving too fast is a major cause of fatal crashes.
You must adjust your speed depending on driving
conditions. These include traction, curves, visibility,
traffic and hills.
2.6.1 – Stopping Distance
Perception Distance + Reaction Distance + Braking
Distance = Total Stopping Distance
Perception distance. The distance your vehicle
travels, in ideal conditions; from the time your eyes
see a hazard until your brain recognizes it. Keep in
mind certain mental and physical conditions can
affect your perception distance. It can be affected
greatly depending on visibility and the hazard itself.
The average perception time for an alert driver is 1¾
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seconds. At 55 mph this accounts for 142 feet
traveled.
Reaction distance. The distance you will continue
to travel, in ideal conditions; before you physically
hit the brakes, in response to a hazard seen ahead.
The average driver has a reaction time of ¾ second
to 1 second. At 55 mph this accounts for 61 feet
traveled.
Braking distance. The distance your vehicle will
travel, in ideal conditions; while you are braking. At
55 mph on dry pavement with good brakes, it can
take about 216 feet.
Total stopping distance. The total minimum
distance your vehicle has traveled, in ideal
conditions; with everything considered, including
perception distance, reaction distance and braking
distance, until you can bring your vehicle to a
complete stop. At 55 mph, your vehicle will travel a
minimum of 419 feet. See Figure 2.11.
Figure 2.11
The Effect of Speed on Stopping Distance.
The faster you drive, the greater the impact or
striking power of your vehicle. When you double
your speed from 20 to 40 mph the impact is 4 times
greater. The braking distance is also 4 times longer.
Triple the speed from 20 to 60 mph and the impact
and braking distance is 9 times greater. At 60 mph,
your stopping distance is greater than the length of
a football field. Increase the speed to 80 mph and
the impact and braking distance are 16 times
greater than at 20 mph. High speeds greatly
increase the severity of crashes and stopping
distances. By slowing down, you can reduce
braking distance.
The Effect of Vehicle Weight on Stopping
Distance. The heavier the vehicle, the more work
the brakes must do to stop it, and the more heat they
absorb. But the brakes, tires, springs, and shock
absorbers on heavy vehicles are designed to work
best when the vehicle is fully loaded. Empty trucks
require greater stopping distances because an
empty vehicle has less traction.
2.6.2 – Matching Speed to the Road Surface
You can't steer or brake a vehicle unless you have
traction. Traction is friction between the tires and the
road. There are some road conditions that reduce
traction and call for lower speeds.
Slippery Surfaces. It will take longer to stop, and it
will be harder to turn without skidding, when the
road is slippery. Wet roads can double stopping
distance. You must drive slower to be able to stop
in the same distance as on a dry road. Reduce
speed by about one-third (e.g., slow from 55 to
about 35 mph) on a wet road. On packed snow,
reduce speed by a half, or more. If the surface is icy,
reduce speed to a crawl and stop driving as soon as
you can safely do so.
Identifying Slippery Surfaces. Sometimes it's
hard to know if the road is slippery. Here are some
signs of slippery roads:
Shaded Areas. Shady parts of the road will remain
icy and slippery long after open areas have melted.
Bridges. When the temperature drops, bridges will
freeze before the road will. Be especially careful
when the temperature is close to 32 degrees
Fahrenheit.
Melting Ice. Slight melting will make ice wet. Wet
ice is much more slippery than ice that is not wet.
Black Ice. Black ice is a thin layer that is clear
enough that you can see the road underneath it. It
makes the road look wet. Any time the temperature
is below freezing and the road looks wet, watch out
for black ice.
Vehicle Icing. An easy way to check for ice is to
open the window and feel the front of the mirror,
mirror support, or antenna. If there's ice on these,
the road surface is probably starting to ice up.
Just After Rain Begins. Right after it starts to
rain, the water mixes with oil left on the road by
vehicles. This makes the road very slippery. If the
rain continues, it will wash the oil away.
Hydroplaning. In some weather, water or slush
collects on the road. When this happens, your
vehicle can hydroplane. It's like water skiing--the
tires lose their contact with the road and have little
or no traction. You may not be able to steer or
brake. You can regain control by releasing the
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accelerator and pushing in the clutch. This will slow
your vehicle and let the wheels turn freely. If the
vehicle is hydroplaning, do not use the brakes to
slow down. If the drive wheels start to skid, push in
the clutch to let them turn freely.
It does not take a lot of water to cause hydroplaning.
Hydroplaning can occur at speeds as low as 30 mph
if there is a lot of water. Hydroplaning is more likely
if tire pressure is low, or the tread is worn. (The
grooves in a tire carry away the water; if they aren't
deep, they don't work well.)
Road surfaces where water can collect can create
conditions that cause a vehicle to hydroplane.
Watch for clear reflections, tire splashes, and
raindrops on the road. These are indications of
standing water.
2.6.3 – Speed and Curves
Drivers must adjust their speed for curves in the
road. If you take a curve too fast, two things can
happen. The tires can lose their traction and
continue straight ahead, so you skid off the road. Or,
the tires may keep their traction and the vehicle rolls
over. Tests have shown that trucks with a high
center of gravity can roll over at the posted speed
limit for a curve.
Slow to a safe speed before you enter a curve.
Braking in a curve is dangerous because it is easier
to lock the wheels and cause a skid. Slow down as
needed. Don't ever exceed the posted speed limit
for the curve. Be in a gear that will let you accelerate
slightly in the curve. This will help you keep control.
2.6.4 – Speed and Distance Ahead
You should always be able to stop within the
distance you can see ahead. Fog, rain, or other
conditions may require that you slowdown to be
able to stop in the distance you can see. At night,
you can't see as far with low beams as you can with
high beams. When you must use low beams, slow
down.
2.6.5 – Speed and Traffic Flow
When you're driving in heavy traffic, the safest
speed is the speed of other vehicles. Vehicles going
the same direction at the same speed are not likely
to run into one another. In many states, speed limits
are lower for trucks and buses than for cars. It can
vary as much as 15 mph. Use extra caution when
you change lanes or pass on these roadways. Drive
at the speed of the traffic, if you can without going
at an illegal or unsafe speed. Keep a safe following
distance.
The main reason drivers exceed speed limits is to
save time. But, anyone trying to drive faster than the
speed of traffic will not be able to save much time.
The risks involved are not worth it. If you go faster
than the speed of other traffic, you'll have to keep
passing other vehicles. This increases the chance
of a crash, and it is more tiring. Fatigue increases
the chance of a crash. Going with the flow of traffic
is safer and easier.
2.6.6 – Speed on Downgrades
Your vehicle's speed will increase on downgrades
because of gravity. Your most important objective is
to select and maintain a speed that is not too fast for
the:
Total weight of the vehicle and cargo.
Length of the grade.
Steepness of the grade.
Road conditions.
Weather.
If a speed limit is posted, or there is a sign indicating
"Maximum Safe Speed," never exceed the speed
shown. Also, look for and heed warning signs
indicating the length and steepness of the grade.
You must use the braking effect of the engine as the
principal way of controlling your speed on
downgrades. The braking effect of the engine is
greatest when it is near the governed rpms and the
transmission is in the lower gears. Save your brakes
so you will be able to slow or stop as required by
road and traffic conditions. Shift your transmission
to a low gear before starting down the grade and
use the proper braking techniques. Please read
carefully the section on going down long, steep
downgrades safely in "Mountain Driving."
2.6.7 – Roadway Work Zones
Speeding traffic is the number one cause of injury
and death in roadway work zones. Observe the
posted speed limits at all times when approaching
and driving through a work zone. Watch your
speedometer, and don’t allow your speed to creep
up as you drive through long sections of road
construction. Decrease your speed for adverse
weather or road conditions. Decrease your speed
even further when a worker is close to the roadway.
Subsections 2.4, 2.5, and 2.6
Test Your Knowledge
1. How far ahead does the manual say you
should look?
2. What are two main things to look for ahead?
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3. What's your most important way to see the
sides and rear of your vehicle?
4. What does "communicating" mean in safe
driving?
5. Where should you place reflectors when
stopped on a divided highway?
6. What three things add up to total stopping
distance?
7. If you go twice as fast, will your stopping
distance increase by two or four times?
8. Empty trucks have the best braking. True or
False?
9. What is hydroplaning?
10. What is "black ice”?
These questions may be on the test. If you can't
answer them all, re-read subsections 2.4, 2.5, and
2.6.
To know how much space you have, wait until the
vehicle ahead passes a shadow on the road, a
pavement marking, or some other clear landmark.
Then count off the seconds like this: "one thousand-
and-one, one thousand-and-two" and so on, until
you reach the same spot. Compare your count with
the rule of one second for every ten feet of length.
If you are driving a 40-foot truck and only counted
up to 2 seconds, you're too close. Drop back a little
and count again until you have 4 seconds of
following distance (or 5 seconds, if you're going over
40 mph). After a little practice, you will know how far
back you should be. Remember to add 1 second for
speeds above 40 mph. Also remember that when
the road is slippery, you need much more space to
stop.
2.7 – Managing Space
To be a safe driver, you need space all around your
vehicle. When things go wrong, space gives you
time to think and to take action.
To have space available when something goes
wrong, you need to manage space. While this is true
for all drivers, it is very important for large vehicles.
They take up more space and they require more
space for stopping and turning.
2.7.1 – Space Ahead
Of all the space around your vehicle, it is the area
ahead of the vehicle--the space you're driving into -
-that is most important.
The Need for Space Ahead. You need space
ahead in case you must suddenly stop. According
to accident reports, the vehicle that trucks and
buses most often run into is the one in front of them.
The most frequent cause is following too closely.
Remember, if the vehicle ahead of you is smaller
than yours, it can probably stop faster than you can.
You may crash if you are following too closely.
How Much Space? How much space should you
keep in front of you? One good rule says you need
at least one second for each 10 feet of vehicle
length at speeds below 40 mph. At greater speeds,
you must add 1 second for safety. For example, if
you are driving a 40-foot vehicle, you should leave
4 seconds between you and the vehicle ahead. In a
60-foot rig, you'll need 6 seconds. Over 40 mph,
you'd need 5 seconds for a 40-foot vehicle and 7
seconds for a 60-foot vehicle. See Figure 2.12.
Figure 2.12
2.7.2 – Space Behind
You can't stop others from following you too closely.
But there are things you can do to make it safer.
Stay to the Right. Heavy vehicles are often
tailgated when they can't keep up with the speed of
traffic. This often happens when you're going uphill.
If a heavy load is slowing you down, stay in the right
lane if you can. Going uphill, you should not pass
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