Virginia Driver Education
Module Three
Vision, Vehicle
Balance and
Laws of Nature
Virginia Department of Education
Module Three
Vision, Vehicle Balance and Laws of Nature
Topic 1 Starting, Securing and Exiting
Topic 2 Vision and Driving
Topic 3 Steering and Braking
Topic 4 Laws of Nature
Topic 5 Establishing Vehicle Reference Points
Topic 1 - Starting Tasks
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•
Check/set park brake (P) and place
Right foot on brake pedal, heel on
floor
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•
•
•
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Left foot on “dead pedal” for balance
Key in ignition, and turn toward start
Check alert, warning lights and gauges
Adjust ventilation, accessories, etc
Turn headlights on
Securing the Vehicle
•
Find a legal, safe parking place
•
Stop and set parking brake
•
Shift gear selector to (P)ark
(Shift to Reverse if Manual Transmission)
•
Close windows
•
Turn off accessories
•
Turn ignition switch to “off”
•
Lock ignition switch and remove key
•
Unfasten occupant restraints
Exiting the Vehicle
• Check traffic flow to rear prior to
•
•
•
•
opening door
Monitor door swing into adjacent lane or
when parked next to another vehicle
Exit quickly to avoid conflict with traffic
Lock doors
Walk toward rear of the vehicle facing traffic
Topic 2 - Vision and Driving
Drivers base about 90% of all
decisions on what they see, and
10% on what they hear or feel
driving
• Drivers must be able to look far enough ahead to make
good decisions about speed, lane position, signs, signals,
markings, and potential hazards
• Drivers must be able to see near and far--close enough to
read the speedometer, and far enough ahead to see/adjust
for hazards
Visual Testing
Visual acuity is the
measurement of the finest
details which can be seen in
optimal light conditions
Effective Use of Visual Fields
The Three Visual Fields
• Fovea Vision
Visual Lead, Targeting, Signs, Signals
• Central
Referencing, Path of Travel
• Peripheral Vision
Motion and Color Changes
The Fovea Vision Area
Located at the center of the
central vision area, the fovea is
a small part of the retina and is
responsible for our highest
visual acuity
Central Vision
Central Vision Area
(Inner Fringe)
An area 35 to 38
degrees around foveal
vision used for:
• Referencing Vehicle Position to Roadway
• Viewing Path of Travel
Central Vision at Night
• The human eye’s field of vision is much smaller
without the help of natural light
• Depth perception, visual acuity, and color
recognition are all compromised at night
• Minimize glare by looking at the bottom right of
the road to avoid approaching headlights
• Keep it dark in the car
• Slow down to give yourself longer to react
Peripheral Vision
Approximately 90 of vision to each side
Increases total field of vision
to about 180-190 and is used
to see:
• Objects to the side
• Movement and color changes
to the side
Peripheral Vision and the Driving Task
Drivers use peripheral vision to:
• See color and object movement
• See signal changes, road signs,
warning lights on the dashboard
• Monitor traffic
• Stay within the lane
Night Time Peripheral
Vision
• Is reduced dramatically due to lack of
light to retina and glare
• While Foveal and Central Vision are
also reduced, they become more
critical for searching for problems
Vision is Affected by
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•
•
•
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Speed
Fatigue
Drugs
Poor weather
Darkness
Glare
Inattention
• Smoke
• Age
• Dirty Windshield
• Poor Windshield Wipers
• Poor night vision
• Night Blindness
Depth Perception
Need both eyes to judge the
distance between two objects
Depth perception allows you to:
• judge gaps in traffic when turning, merging, or
passing
• judge distance when approaching a vehicle or
obstruction
Poor Depth Perception
• Stop too far from the stop line or intersection
• Stop too close to vehicles ahead
• Move into gaps that are too small
• Look for gaps that are larger than needed to perform
a maneuver
• Follow other vehicles at unsafe following distance
• Hit parked cars when parking
• Have “close calls” when entering traffic, passing, etc.
As speed increases
•
•
•
Central vision decreases and blurs
Peripheral vision decreases
Changes in steering exaggerate vehicle
movement
VISION FIELDS
NARROW
Ways to Improve the Vision Fields
• Clean windows—inside and out
• Clean lights—be sure they work
• Check defroster and wiper blades
• Remove any objects that interfere with vision
• Adjust mirrors properly
• Keep sunglasses, flashlight, windshield scraper in
vehicle
Line of Sight
Line-of-sight is the distance you can
see in your path of travel
Line-of-Sight (LOS) Restrictions
Vision is blocked, speed and position adjustments
may be needed until LOS is restored
Path-of-Travel (POT)
The space the vehicle will occupy
while traveling to the target area
Examples of Path-of-Travel Restrictions
Space is not available for the vehicle
Narrow lane and no
shoulder
Vehicle stopped or
blocking intersection
“Target” Far Ahead in the Path of Travel
Identify the target in this driver’s path of
travel
A “Target” is an object
or place far ahead in the
center of your path of
travel
Target AREA Provides the BIG Picture
The Target area is the
area drivers must scan
to the left and right of
the target
Target Area
Advantages of
Targeting
• Easier to track vehicle in a straight line
• Driver looks far ahead of the vehicle, and at the
same time gathers information close to the vehicle
• Driver can plan ahead to better manage risks
• Targeting develops visual skills essential for
managing traction loss and steering control
The Pavement Around Your Vehicle
You Cannot See From the Driver’s Seat
The driver cannot see anything on the ground in the area
outlined above—cars are used to show the size of this area
Determining Driver Blind Areas
Marker (foot or cone)
Place markers (cones,
people) at the point where
the driver can see the
marker, (cone, person’s
foot) in contact with the
ground
Using Lane Position to
Maximize LOS
1
• Select the lane position that
gives you the best line of sight
and safest path of travel
• Lane positions are based upon
an average lane size of 12-feet
wide, and a vehicle 6-feet wide
2
3
4
5
Lane Position 1
2-3 Feet
2-3 Feet
Positioned in the center of lane with an
equal buffer of space on either side
Lane Position 2
3-6 Inches
Allows for 6 feet of space to the right of the vehicle.
Used to prepare for a left turn or when avoiding a
problem to the right of the vehicle.
Lane Position 3
3-6 Inches
Allows for 6 feet of space to the left of the vehicle.
Used to prepare for a right turn or when avoiding a
problem to the left of the vehicle.
Lane Positions 4 and 5
4
5
Lane positions 4 and 5 – straddling the
line to avoid a problem within a lane
Topic 3 - Basic Maneuvers -- Steering
Holding the upper half of the wheel can result in
excessive steering, air bag injuries, and upper body
fatigue
Hands located on lower half of the
wheel offers:
• Relaxed, balanced control
• Reduces unwanted steering wheel
movement
• Improves stability by lowering the
body’s center of gravity
Hand-to-Hand/Push-Pull Steering
Hand-to-Hand Steering/Push-Pull
Right Turn
Right Turn
Left Hand
Pushes Up
from 8 to 11
Right Hand
Pulls Down
from 1 to 4
Hand-Over-Hand Steering
Used at Speeds below 15 mph
Used for slow, tight turns - Arms cross on the top 1/3
of the wheel until desired path of travel is reached
Left Turn/left hand
Left hand pulls down, then
reaches up to about
theo’clock position and
continues to pull 11-12
down to the left
Left Turn/right
hand
Right Hand pushes up
to about the 11
o’clock position
One-Hand Steering
Is used when:
• Backing straight--hand
holds top of wheel
• Backing a trailer--hand
holds bottom of wheel
Backing Position
Covering the Accelerator
• Used for a smooth transition from braking to
accelerating
• Allows the vehicle to coast which may speed up or
slow down the vehicle
• Permits the driver to be prepared for any needed
acceleration
Foot Pedals
Right foot pivots between brake and accelerator
Dead Pedal
Brake
Accelerator
Left foot “rests” on dead pedal
Acceleration Techniques
1. Progressive, Smooth Acceleration
• Heel pivots foot from the brake to the
accelerator
• Gently apply pressure to the accelerator pedal
to gradually increase speed to minimize
backward pitch and maintain vehicle balance
Acceleration Techniques (cont)
2. Thrust Acceleration
• Typically used when passing or merging into
higher speed traffic
• Greater pressure is applied to accelerator
pedal to rapidly increase speed without losing
tire traction
Braking Techniques
Smooth braking technique:
• Is a trait of a skilled driver
• Saves wear and tear on the brake system and
tires
Methods to Reduce Speed
Release the Accelerator
• Most frequently used method to
slow vehicle speed
• Gradually reduce pedal pressure
to avoid abrupt changes in speed
Methods to Reduce Speed
2. Controlled Braking - When releasing the
accelerator is not enough
•
Check the rear view mirror
•
Release accelerator and apply smooth, steady pressure
on the brake pedal
•
For a smooth STOP, gently ease off the brake a few
seconds before stopping to reduce the vehicle’s weight
shift so the car does not pitch forward then backward
during the final phase of stopping
Methods to Reduce Speed (cont)
3.
Threshold Braking in an Emergency
Slows the vehicle as quickly as possible without
locking brakes or losing traction
•
Release accelerator while checking traffic behind
•
Exert forceful pressure on brake pedal and you will
feel the vehicle weight shift forward
•
If you feel the wheels begin to slide, ease the
pressure on brake pedal so the tires can begin
rotating again
Methods to Reduce Speed (cont.)
4. Trail Braking – Used for Sharp Turns
Occurs at the transition point
where you slightly reduce
on the brake pedal to allow
vehicle to begin to regain speed
applying the accelerator
pressure
the
before
Trail Braking
1. Use controlled braking prior to reaching
the curve
2. Begin easing off brake, and trail brake
with very light pressure until halfway
through the turn,
3. Accelerate out of the turn
Anti-Lock Braking System (ABS)
ABS allows maximum stopping force without locking up the
brakes (skidding)
If standard brakes are applied too hard, the wheels "lock"
or skid, and you lose steering control.
Anti-Lock Braking System (cont)
If steering control is lost, the vehicle skids in a straight line
wherever it is going
ABS is an anti-lock/anti-skid brake system that allows the driver
to steer during hard braking
Anti-Lock Braking System (cont.)
• The ABS warning will come on when
there is a problem with either the ABS
brake system, normal brake system, or
the brake fluid is low in the master
cylinder or the ABS brake system
• To find out if a vehicle is equipped with
ABS, turn on the ignition and check the
instrument panel for the ABS indicator
light
Practice Activating ABS
•
In a parking lot, go 20-25 mph and execute
an emergency stop to engage ABS
•
Keep your foot firmly on the brake even
when you feel the brake pulsate and/or
hear noise
•
This computerized pumping action can
pump the brakes up to 15 times per
second
Myths about ABS
• There are fewer fatal crashes for cars
equipped with ABS
False, some drivers panic and/or release the
brake when it pulses
•
Don’t use ABS brakes on a slippery surface
False, ABS shortens stopping distance and improves
control on a slippery roads
Maintaining Vehicle Balance
•
Vehicle balance is the distribution of the weight of the
vehicle on the tires
•
Optimum balance is reached when the
vehicle is not moving or is moving in a straight direction
at a constant speed
•
As soon as the vehicle accelerates, brakes, or turns, the
balance is changed and the weight transfer changes the
size of the tire patches
Gravity
The natural force that pulls all
things to Earth
• Throw a ball into the air and what happens?
• Gravity gives objects their ___________gravity
• The center of gravity is where a body’s mass
is ___________
Energy of Motion = Speed x Mass
The white truck
and the dump
truck are going the
same speed
Which vehicle has more energy of motion?
Why?
Effect Of Speed And Weight
• The kinetic energy of a 4,000 pound vehicle traveling
at 100 mph is equal to 1.36 million foot pounds –
enough to lift a 175 pound man 1.5 miles!
• To stop a vehicle going 60 mph would generate
approximately enough heat to boil one-half gallon of
water!
Inertia
• Inertia wants to keep these parked vehicles
at rest
• Inertia also wants to keep these moving
vehicles moving
Inertia
(cont.)
When driving through this
curve, inertia creates the
sensation that you are
being pulled toward the
outside of the curve
Why?
Because you are traveling in a straight line, and
inertia wants to keep you going in a straight line
Momentum = Mass x Velocity
• Momentum is inertia in motion
• Momentum is the product of speed and weight
A small truck filled with potatoes
traveling at 20mph has more
momentum that a 3,000 lb car
traveling at the same speed
As momentum increases so does the potential for damage
in a collision
Pitch, Roll, and Yaw
Pitch, Roll, and Yaw are the three axes running
through a vehicle’s center of gravity
Yall
Pitch
Roll
Vehicle Pitch
Vehicle’s weight shifts backward or forward
Backward Pitch:
Forward Pitch
Changing Vehicle Load from
Front to Rear
Changing Vehicle Load from
Rear to Front
• Accelerating
• Releasing the accelerator
• Releasing the brake
• Braking
Vehicle Roll
Roll: Vehicle’s weight shifts to the tires
located on one side of the vehicle
Which direction is this driver steering to cause this
weight shift? What causes a vehicle roll over?
Vehicle Yaw
Yaw: Fishtailing
No Yaw
Vehicle’s rear tires lose
traction and weight shifts
to one side while
opposite rear wheel
moves toward front of
vehicle
Yaw
Steering For Balance And Control
• Sit at a safe distance
from the wheel
• Use a balanced hand
position
• As speed increases,
steering input is
reduced for turns and
other maneuvers
Photo courtesy of ADTSEA
Changes in Speed Affects
Balance and Control
• Pushing or releasing the accelerator
pedal is the primary method to adjust
the speed of a vehicle
• Changes in speed causes weight shifts
to front or rear tires
• Increases in speed with steering
adjustments causes significant shifts
in the vehicle’s weight
Braking Affects Balance and Control
How does braking affect balance and control in a front or
rear-wheel drive vehicle?
Effect of Hard Braking and Steering
• Applying hard braking causes weight to shift sharply
to the front tires
• If the weight shift exceeds available traction, the tires
will skid and steering control is lost (under steer)
Vehicle Suspension System
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•
•
Helps to smooth out weight transfers
Helps keep all four wheels on the ground
Helps keep the vehicle level
Steering and Balance
Accelerating, braking, or steering shifts the vehicle’s weight from
tire to tire and affects vehicle balance and control
Describe the driver’s action and how is it affecting this
vehicle’s balance?
Maintaining Vehicle Balance
Describe the driving maneuvers that create
these tire footprints
Maintaining Vehicle Balance (cont.)
Describe the driving maneuvers that create
these tire footprints
Vehicle Load
Vehicle load capacity includes the combined
weight of people, liquids and cargo that the
vehicle is designed to safely handle
Effect of Load On Vehicle Balance
What could occur if
the driver of this
vehicle made a
quick steering
maneuver?
Photo courtesy of AAA Foundation
Vehicle Over Load
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•
Operating a vehicle above the Gross Vehicle Weight Rating
(GVWR) compromises safety
Frame, suspension, brakes and tires are not designed for
weights above the rating the manufacturer has set
Standard Vehicle Reference Points
LEFT Reference Point
3 feet from line
or median
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•
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6 inches from line
or median
Relates a part of the vehicle to some part of the roadway
Know your vehicle placement within a lane at all times
Maneuver in confined places
Standard Vehicle Reference Points
RIGHT Reference Point
3 feet from
line or curb
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•
•
6 inches from
line or curb
Relates a part of the vehicle to some part of the roadway
Know your vehicle placement within a lane at all times
Maneuver in confined places
Standard Vehicle Reference Points
Left Side Reference (3-6 Inches)
When you look at the curb,
pavement line, or edge of the
road, it appears to line up about
one foot in from the left edge of
the hood
Standard Vehicle Reference Points
Left-Side Reference Point
Used for:
• Lane Position 2
• Preparing for a left turn
• Determining position for
parking on the left side of a
one-way street (3-6 inches from
the curb or line)
Standard Vehicle Reference Points
Right Side Reference Point
Your vehicle is 3-6 inches from the
curb, pavement line or edge of the
road when the line appears near
the center of the hood
Standard Vehicle Reference Points
Right Side Reference Points
Are Used:
• To know where the curb or line is
located
• For Lane Position 3
• For parking
Standard Vehicle Reference Points
To Position Vehicle Three Feet
Away
When you look at the
curb, pavement, or
edge of the road, it
appears to line up with
the middle of the righthalf of the hood
Standard Vehicle Reference Points
Right Side -- Three Feet Away
• To position for a right
turn or for
• Lane Position 1
Standard Vehicle Reference Points
Front Limitation
To position 3-6 inches from the line in front of your
bumper, stop when your line of sight runs under
the side view mirror to curb in front
Standard Vehicle Reference Points
Front Limitation
You will need to know where the front bumper of your
vehicle is when you are:
• At intersections
• At a stopped
position
• When parking
• At a crosswalk
STOP LINE
Standard Vehicle Reference Points
Front Limitation
When you look at the curb line it appears to line up
with the side view mirror
Standard Vehicle Reference Points
Rear Limitations
LEFT
When you look back over your left
shoulder, the curb or line appears to be in
the middle of the left rear window
RIGHT
When you look back over your right
shoulder, the curb or line appears to be
near the rear window corner
Standard Vehicle Reference Points
Rear Limitations – How They are Used
LEFT
When backing to know where
your rear bumper is
RIGHT
When backing around a corner,
it’s the pivot point for turning,
such as backing into a
perpendicular parking space