Adverse
Conditions
Driving Problems
Caused by Reduced
Visibility
Traction
& Space
Click for Version & Contact Information
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Adverse
Conditions
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Adverse
Conditions
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Adverse Conditions
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Clip: Very Adverse
Conditions!
Adverse Conditions
Contents
 General Info
 Skid Control &
Prevention
 Antilock Brake
Systems
 Hydroplaning
 Winter Driving
 Fog Driving
 Night Driving
Slide 5 + © PED
Adverse Conditions
Accident Facts
 Nearly 1 million
crashes occur every
year due to reduced
traction under
adverse driving
conditions. [NHTSA]
 These are caused by
drivers who fail to
adjust techniques to
account for adverse
conditions. [NHTSA]
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Adverse Conditions
Preventable?
Would your driving habits
change if you knew this
was going to happen?
Why not drive differently all
the time?
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Adverse Conditions
Recognition
 To drive safely,
you have to
recognize the
demands that
you, your vehicle,
& your tires face.
 Many motorists
fail to adjust their
techniques –
setting the stage
for loss of
control.
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Adverse Conditions
Recognition
How much time should be built
into your trip when weather
conditions change?
What happens if you don’t
adjust your schedule?
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Adverse Conditions
Perception,
Recognition,
Response
How much traction
is available to you
at this moment?
How would you
know that?
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Adverse Conditions
Driving in Adverse
Conditions
 Drive more slowly:
 As
your speed decreases, the tire
footprint increases, providing
better traction
 Maintain a safe distance:
 2X
or 3X the normal space cushion
 Be extra alert at intersections:
 Check
for other vehicles that are
not adjusting for current
conditions
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Adverse Conditions
Tire Performance
 Know the
performance
characteristics of
your tires:
 Tires are
designed for
differing levels of
performance
under various
weather,
temperature &
wear conditions
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Adverse Conditions
Tire Maintenance
 Tires cannot provide
good wet traction
once the tread depth
is worn below 1/16 of
an inch
 Check tires twice a
month for wear & tear
with the penny test
 Maintain proper air
pressure at all times
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Adverse Conditions
Smart Thinking!
 Think ahead about your
driving:
 Know
the adjustments
needed for current weather
conditions
 Be knowledgeable about
your tires:
 Make
sure your vehicle is
equipped with the correct
performance tires;
 When in doubt ask a tire
dealer for information
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Adverse Conditions
Planning Ahead
 Drive smoothly:
 Avoid
abrupt braking,
accelerating, or
turning
 Plan your braking:
 Slow
down prior to a
curve or a hill;
 This
will reduce your
braking distance
while increasing
traction
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Adverse Conditions
Accident Facts
If you don’t build extra
space or time into
adverse conditions…
You will likely experience
situations that will lead to
collisions!
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Adverse Conditions
When would be the
best time to adjust
speed or position as
you approach curves?
Why?
Slide 17 + © PED
Timing is
Everything
Adverse Conditions
Alternatives
 Is this trip necessary?
 Can the trip be delayed
until traction improves?
 Can the trip be
accomplished another
way (phone, Internet)?
 Can different trips be
combined to minimize
traffic & environmental
exposure?
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Adverse Conditions
Driver Readiness
 Get the proper
mental state:
 The
ability to focus
is essential
 Get proper rest:
 Help
maintain the
alertness needed to
handle the extra
demands &
increased reaction
times
Slide 19 + © PED
Adverse Conditions
Vehicle Readiness
 Know the weather
forecast before
you get on the
highway
 Keep your
windshield wipers
in good condition
 Check windshield
washer fluid
regularly
Slide 20 + © PED
Adverse Conditions
Vehicle Readiness
Test both low beams &
high beams before a
trip
 Have your headlights
checked annually for
proper orientation &
focus
 Check fluid levels, tire
pressure, lights, &
battery
 Have a mechanic give
your vehicle a winter
readiness check

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Adverse Conditions
Don’t Forget
 Always use
your safety
belt!
 Turn your
headlights on
 Bridges &
overpasses
freeze before
other roadways
do
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Adverse
Conditions
Skid
Control &
Prevention
Slide 23 + © PED
Adverse Conditions
Why Skids Happen
 Skids happen
whenever tires lose
their grip on the road
 Tires lose their grip
for 1 of 4 reasons:
 Overbraking
 Oversteering
 Overacceleration
 Driving
Slide 24 + © PED
too fast
Adverse Conditions


Why Skids Happen
Overbraking:

Braking too hard &
locking up the wheels;

Braking when the road
is slippery
Oversteering:

Turning the wheels
more sharply than the
vehicle can turn
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
Overacceleration:


Supplying too much
power to the drive
wheels, causing them
to spin
Driving too fast:

Approaching hazards
so quickly that there is
no time to recognize &
react properly
Skid Control
Adverse Conditions
Slide 26 + © PED

Skidding occurs whenever
the force applied to the tire
exceeds the tire’s traction

Your goal must be to keep
the tires below the
threshold of skidding

Even the best skid-control
skills won’t prevent a
collision if the available
room is less than the
space required to stop or
escape
Adverse Conditions
Skid Control
How do you keep
your car below the
threshold of
skidding?
How do you steer
out of a skid?
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Adverse Conditions
Skids on Dry
Surfaces
 Most skids, spins, &
slides happen on wet,
icy, or snow-packed
surfaces
 Loss of control can
also happen on dry
surfaces when you
combine high speeds
with quick changes in
direction
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Adverse Conditions
Skid Practice
 Once your vehicle
skids more than
45° you cannot
recover control
 Skid recovery is
an acquired skill
that must be
practiced if you
are going to be
confident in reallife situations
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Adverse Conditions
Skid Practice
 Skid recovery
calls for an
unnatural
response by
the driver
 Find a
deserted
parking lot
with no
obstructions
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Adverse Conditions
Slide 31 + © PED
Clip: Skid Practice
Adverse Conditions
Skid Prevention
Explain why skid
prevention is the
key to skid control.
How would you
apply this strategy?
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Adverse Conditions
Tailgating
 Your exit options
are reduced when
you tailgate
 A skid or a slide
can result
because you are
unable to adjust
speed, space, or
direction in a
controlled
manner
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Adverse
Conditions
Antilock
Brake
Systems
Slide 34 + © PED
Adverse Conditions
Antilock Brakes
 Antilock brake systems can
stop more quickly than
conventional brakes on wet,
icy, & snow-packed roads
 Antilock brakes prevent the
wheels from locking during
emergency braking situations
 Antilock brakes allow drivers
to maintain steering control
 Check the dashboard for the
ABS symbol
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Adverse Conditions
Slide 36 + © PED
Antilock Brakes

When used properly, 4wheel ABS is a safe,
effective braking system

Antilock brakes cannot
compensate for
aggressive driving

Antilock brakes cannot
guarantee recovery from a
skid

Avoid extreme steering
manuevers while your
ABS is engaged
Adverse Conditions
2 Types of ABS
 4-wheel ABS:
 Generally
cars;
found on passenger
 Designed
to maintain steering
ability in emergency braking
situations
 Rear-wheel ABS:
 Found exclusively
 Designed
on light trucks;
to prevent the vehicle
from skidding laterally
Slide 37 + © PED
Adverse Conditions
ABS Shortcomings
 Antilock brakes are
less effective on
certain roadways:
 Extremely
icy roads;
 Freshly fallen
 Gravel
snow;
roads
 Don’t count on the
ABS—continue to
drive cautiously
Slide 38 + © PED
ABS Do’s
Adverse Conditions
 Do maintain firm & continuous
pressure on the brake while
steering to enable 4-wheel
ABS to work properly
 Do allow enough distance to
stop:
 Follow
4 or more seconds
behind vehicles if conditions
are good;
 Follow
6 or more seconds if
conditions are adverse
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Adverse Conditions
ABS Do’s
 Do practice with
ABS in empty
parking lots to
become familiar
with the pedal
pulsations
 Do consult the
owner’s manual
for additional
instructions
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Adverse Conditions
ABS Don’ts
 Don’t drive an ABS-
equipped vehicle more
aggressively
 Don’t pump the brakes:
 Pumping
the brake
turns the ABS system
on & off
 Don’t be alarmed by
the noises & pedal
pulsations
 Don’t forget to steer
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Adverse Conditions
What can ABS do
for you?
What can’t it do
for you?
What can you do
to remember this
vital information?
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Antilock Brakes
Adverse
Conditions
Hydroplaning
Slide 43 + © PED
Adverse Conditions
Hydroplaning
 During a heavy
downpour, water
on the pavement
can cause your
vehicle to
hydroplane
 Your front wheels
ride on a wedge of
pressurized water
& rise off the road
surface
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Adverse Conditions
Hydroplaning

Since your wheels
no longer contact
the road, you will
experience a partial
or total loss of
steering control

The only solution is
to reduce speed:

Slide 45 + © PED
Gently reduce
pressure on the
accelerator to bring
the speed down
Adverse Conditions
Summer Icing
When rainfall begins, water mixes with oil
& debris from the pavement, creating very
slick conditions
 Drivers often forget this potential hazard,
creating dangerous situations
 Reduce speed & test traction early & often

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Adverse
Conditions
Winter
Driving
Slide 47 + © PED
Adverse Conditions
Enough Space
Time & Traction?
How do multicar
collisions happen?
What should have
been done to prevent
this from happening?
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Adverse Conditions
Awareness
 Most drivers realize that
winter driving is
different, but lack the
comprehensive
knowledge to handle
changing environments
 Drivers must stay
informed about current
weather conditions, and
how these conditions
will likely change
Slide 49 + © PED
Adverse Conditions
Braking
 Failing to allow enough time to
stop your vehicle is a major
cause of winter driving crashes
 Slippery driving conditions can
triple stopping distances
 Slowing your cruising speed,
anticipating stops &
slowdowns, and increasing
coast & brake times will help
ensure collision-free stops
Slide 50 + © PED
Control
Adverse Conditions

Accelerating, turning, & passing
present dangers during winter:
Accelerate slowly to avoid loss of
traction & subsequent loss of control;
 Turn slowly with caution to avoid
sliding into a stationary object or the
path of an oncoming vehicle;
 Pass with care because passing lanes
are not maintained as well;
 Avoid sudden or swift movements


Slide 51 + © PED
Triple your following distance so
there’s plenty of room to see &
maneuver
Adverse Conditions
Slide 52 + © PED
Clip: Winter
2-Lane Driving
Adverse Conditions
Winter Driving &
Tire Pressure
For every 10° drop in outdoor
temperature, the air pressure
inside your tires drops 1-2 psi
 Regularly check tires for proper
air pressure
 Never reduce air pressure in an
attempt to increase traction on
snow or ice—your tires could be
seriously damaged
 If you get stuck, a spinning tire
could explode when your
speedometer reads over 35 mph

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Adverse Conditions
When does salt
stop working?
Why would you
need to know
that?
How could you
tell if the salt was
becoming
ineffective?
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Road Salt
Adverse Conditions
Slide 55 + © PED
Clip: Winter
City Driving
Adverse Conditions
How much
traction is
available to
you at this
moment?
Why should
you test traction
before the
curve?
Slide 56 + © PED
Traction, Space, &
Visibility Changes
Adverse Conditions
Rocking the Car
 If a tow truck is not
readily available,
gently rock your
vehicle back &
forth
 Repeatedly shift
back & forth from
drive to reverse,
until momentum
carries you out of
the problem area
Slide 57 + © PED
Adverse Conditions
Slide 58 + © PED
Clip: Winter
Highway Driving
Adverse Conditions
Icy Roads
 Although water
freezes at 32°,
road surfaces can
freeze when the
air temperature is
as high as 40°
 Ice on roads is
generally
classified as
either white ice or
black ice
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Adverse Conditions
White Ice
 White ice is usually
visible to the eye
 White ice is usually
created in 1 of 2
ways:
 Compacted
snowfall that has
slightly melted &
then frozen;
 Rainfall
Slide 60 + © PED
that freezes
Black Ice
Adverse Conditions
Black ice is usually not seen until
the vehicle is already on it
 Black ice is usually created by
clear water or condensation that
has frozen on dark pavement
 Black ice usually forms below
overpasses, on bridges, in areas
of run-off, in shaded areas, or
anywhere the ground is below 40
degrees
 Good pavement conditions
located just before these areas
can lull you into a false sense of
security

Slide 61 + © PED
Adverse Conditions
How do you
know if there’s
black or white ice
under the snow
cover?
When do you
need the answer?
What strategies
are needed here?
Slide 62 + © PED
White Ice or
Black Ice?
Adverse Conditions
Slide 63 + © PED
Clip: Black Ice
Adverse Conditions
Describe your
thoughts as you
navigate this road.
What kinds of
conflicts do you
anticipate here?
Slide 64 + © PED
Ice Storms
Adverse Conditions
Winter Driving
Emergency Kit
Heavy clothes & Blanket
 Traction material (sand,
kitty litter)
 Tire chains
 Small shovel
 First aid kit
 Flashlight
 Jumper cables
 Bright cloth to use as an
identifying flag

Slide 65 + © PED
End of Part One
Adverse Conditions

Presentation Version 1.1
Released 2004-10-23

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