Download The Human Element

Let’s Review…
• What are the three components of the
HTS?
The three components of the highway transportation system (HTS) are:
People,
machines,
and the environment they operate them in.
The Problem is People
• 90-95% of vehicle accidents are caused
by people not vehicles or roadways.
Human errors are the problem in traffic
accidents.
Driver Licensing
• The purpose of driver licensing is to make
sure that no user of the HTS is an
unreasonable risk to other users of the
system or themselves.
The EYES have it.
• Most information used when using the
HTS, is acquired visually. Generally, it is
accepted that 90% of driving information is
received through the eyes.
Good vision is not a given
• There are many things which may effect a
person's vision. These are genetics,
fatigue, smoking, alcohol or other drugs,
age, illness such as allergies or colds.
• If 90% of driving information is received
visually, we must have reasonable vision.
NC requires 20/40 corrected vision.
Field of Vision
• Field of vision is all the area you need in
front of you. Normally people can see
180-210 degrees of the area to the front.
Three types of vision
• A. Central vision is the area where you see
things clearly. The DMV eye test
measures visual acuity, how clear central vision
is. About 3 degrees
• B. Fringe vision is outside central vision where
you can recognize objects but not clearly.
From 3 to 90 degrees.
• C. Peripheral vision is the outside of your field of
vision where you see motion but not objects. Up
to 210 degrees
Things that may affect vision
• A. Tunnel vision cause by genetics.
B. Other traffic blocking parts of your field of
vision.
C. Your vehicle's design can block your vision.
D. Illnesses, even temporary illnesses can cause
vision restrictions.
E. Age can reduce a person's field of vision as
well as the other effects age can have on vision.
• Depth perception is the ability to judge
distance.
Color Blind persons
• More common among men
• Red and green go first
Are they an unreasonable risk?
• Although red and green are typically the
affected colors, persons who are color
blind can compensate for the problem and
are no greater risk of collisions because of
this problem.
• Glare resistance is the ability of the pupil
to shut out light (glare). Glare recovery is
the ability of the pupil to reopen once the
bright light is gone and the eye needs to
readjust to low light conditions.
How does alcohol affect vision?
• Alcohol is a sedative. It affects many areas
of the body from mental functions to
relaxing muscles and reflexes.
• Your eyes are a series of muscles. At
higher levels of BAC, your vision is
affected.
How Alcohol affects vision
• A. Slowing the pupil, increasing glare and
slowing glare recovery.
B. Relaxing the muscles that control the lens
reducing visual acuity.
C. Sedating the retina causing problem of color
recognition especially shades of darkness while
driving. (Seeing pedestrians, bicycles or even
the side of trains at night.)
D. Binocular vision. The ability of the eyes to
focus together on an object.
E. Peripheral vision can be narrowed by alcohol.
Can you drive safely at .08?
• . DWI (Driving While Impaired) only
requires that a person have a blood
alcohol concentration of .08 to be
convicted of DWI.
• One reason is that no one can see well
enough, even at .08 BAC to drive safely.
They are an unreasonable risk.
• At .08, the chances of being involved in a
collision is 4 times greater than sober.
There are many disabilities that
may affect a persons ability to
drive. Here are some:
• A. Hearing loss. There is usually no increased risk because of visual
compensation by the driver.
B. Physically challenged persons are not normally a greater risk.
Safe driving is a mental skill so physical limitations can usually be
overcome.
C. Age. Aging affects all of a person's senses. Vision, hearing,
reactions even mental sharpness. These effects often appear over
years and sometimes not recognized by persons as they age.
D. Epileptics are allowed to have a drivers license (class C) if they
are on medication and have gone seizure free for one year.
E. Diabetes is a major problem because of the serious effect of high
or low blood sugar.
F. Mental ability. The DMV officer decides if this person can get a
drivers license.
• G. stroke or heart problems may force doctors to notify DMV about a
patient. Even Alcoholism may be reported to DMV. Let’s not even
talk about alzheimer’s.
I got this index from NHTSA
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Driving and Alzheimer's
Driving When You Have Sleep Apnea
Driving When You Have Parkinsons
Driving When You Have Arthritis
Driving When You Have Cataracts
Driving When You Have Glaucoma
Driving When You Have Diabetes
Driving When You Have Macular Degeneration
Driving When You Have Seizures
Driving When You Are Taking Medications
Driving When You Have Had a Stroke
Scared yet?
Bottom line…
• The bottom line is that anyone driving,
because of health, or experience. Can
and should be restricted from driving.
• Experience = bad driving record. The
reason a state revokes a license is that the
person has proven to be an unreasonable
risk to themselves and others.