Evening star., 1935-10-13
BY GEORGE L. SMITH.

a. Every effect is the result of some
cause. To control the effect, it is
necessary to understand its cause.
This applies just as fully to automobile
accidents as it does to the smooth
running of the engine under the hood.
What has caused the increase in
accidents? Are drivers less expert
enced? Are the roads or the cars not
as safe as they we're in previous years?
Are the brakes less efficient than they
were?
To answer these questions it may be
said that drivers, on the average, must
be more efficient today then they were
10 years ago. otherwise we would have
to admit that experience Is not good
teacher. Roads are in general very
much better. They are smoother and
straighter, with a much better system
of warning signals. Cars may be
safer in some respects, but are they
safer as a completed assembly Of
power plant. steering control, stopping
control, etc? Some engineers say yes
and some say no.
~ Two Questions Proposed.
II a layman may be permitted to
analyze this subject. there appear to
be two main points to be considered
as far as safety of the vehicle is con-
cerned. First, is the average driver
of today as competent to handle the
car of today as the driver of 10 or Is
wears ago was to handle the vehicle
of that time? And, second, has the
improvement in safety features kept
step with the improvement in speed
of travel?
To analyze the first item, the
maximum speed of travel in uncon-
gested areas has increased in the past
10 years as a result of better roads
and more powerful engines from some
figure around so miles an hour to
something like 10 miles an hour. Ten
years ago few cars could make over
70 miles an hour, while today 80 miles
an hour is not impossible. Likewise,
the speed of traffic in congested areas
has increased probably in about the
same proportion.
At a speed of 70 miles per hour the
energy stored up in the vehicle Is al
for so miles per hour. If the destruc-
tive effect of the vehicle is thus dou-
bled by this increase in speed. then
it is sensible to suppose that the
driver of such q vehicle must be twice
as careful and twice as expert. Here
seems to be the first indication OF a
(, plausible cause for the greater number
of accidents of the present day, as 1t
(. is foolish to suppose that any such
increase in ability and efficiency OF
the average driver has taken place IN
the past 10 years. That there has
been a marked increase in his ability
is evident, however, or the accident
rate might easily be much higher.
Car Safety Lags Somewhat.
To consider the second query in
regard to improvement in safety fea-
lures, it is possible that these fea-
lures have Jagged behind in respect
to the prevention of accidents, al
though the car CT today with its
safety glass and all-steel bodies with
turret tops, is safer for those inside
when the accident does take place
From a perusal of reports of motor
vehicle accidents, the word collision
stares me in the face-collision with
pedestrians, collision with automobiles,
collision with horse-drawn vehicles,
collision with railroad trains, collision
with street cars, collision with fixed
objects, etc. Out Of II itemized types
Of accidents on one report inspected,
all are collisions except two, non-col-
usion accident and miscellaneous.
In view of such overwhelming eW-
dence, it would appear that improve
ment in stopping power would avoid
some. at least, Of these collisions, and
this brings up the question Of brakes
how good are they-are they good
enough-can they be improved, and
If so, how? It is the consensus that
brakes have been vastly improved
since the introduction of four wheel
brakes, and this is true, but suspect
that while the stop" experts were
devising better and more efficient
brakes, the "go" experts have been
equally diligent in devising speedier
cars. If, as previously stated, the
energy in the 70-mile- e-an-hour car
is double that of the 5o-mile-an-hour
car, then the "stop" expert had t.
keep busy in order to avoid losing
ground.
Some States Gauge Stops.
If they have made brakes as safe
and powerful as it is mechanically
possible to make them, then they
have done their part. But in looking
up the requirements laid down by
the various States, we find that many
of them specify a stopping distance
of Is to 80 feet at 20 miles an hour
on a good hard road surface. whereas
the best possible distance at this speed
as given by tables computed by brake
experts is II feet. Also note in
remarks on the tables that q stop
in Is feet "is considered an ordi-
narily good practical stopping distance.
Less than that would probably be un-
comfortable for the passengers" This
would indicate that the brake ex-
perts prefer to risk a collision rather
than a shake-up and possibly a few
bruises for the passengers.
1t is plain to any one that maximum
stopping power means power to lock
all four wheels of the car at any speed,
but this has always been considered
But what should cause side skidding?
But what shoul cause side skidding?
If the retarding forces exerted by the
right and left wheels on the road sur
face are balanced, why should there
be any skidding? I find, however.
that they are not balanced. Only the
pressure of the brakes on their drums
Is balanced.
In studying the question of brake
power I find that the conventional
method of brake application is by the
so-called $3.50 method, which means