What’s an average person’s reaction time to a visual
stimulus?
How many feet per second are traveled at 60 miles per hour?
Kevin E. Dayhoff
The context of the statistic was about the
then-“state-of-the-art Lotfernrohr 7 bombsight.”
“The bombsight has a
field of vision of 35 degrees, and has a 1.4-times magnification. This would
mean that you would be looking at a total area of about 115,000 square meters.
Elizabeth Tower, in comparison, has a footprint of 225 square meters, occupying
0.19 percent of your total field of view. For those of you more visually
inclined, it means your sight picture, once you’re right over the tower, looks something like this.
“Now, traveling at 150
kilometers per hour, you will cover the width of the tower’s footprint in a
mere 0.36 seconds, or possibly slightly more than half a second if you’re
coming at it on a direct diagonal.
“What’s an average
person’s reaction time to a visual stimulus? According to data collected by
Human Benchmark: 0.26 seconds.”
As a matter of fact, I thought that I had learned recently,
in an emergency response driver’s training class; that it took the average
person three-quarters of a second to react to visual stimulus.
Or put another way, how long it take you to hit the brakes
after you see a problem ahead? And how many feet do you continue to travel
during the time it takes you to react and hit the brakes?
Let’s look at it this way; if your reaction time is ¾
second, and you use the formula, “MPH X 1.5,” whatever that means – I’m not
sure I understand my own notes… Anyway, at 40 mph you travel 60 ft per second,
and if it takes you ¾ second to react, you have already traveled 45 foot
towards an observed road hazard.
Perhaps we will need to consult with one of our many
Westminster brainiac engineers. Jason Tyler or Mark Arnold, can you make sense
out of this? Please explain.
Does it take ¼ of a second to react or ¾ of a second to
react? How many feet does one travel in a car, per second, at 40 miles per hour
– or 60 miles per hour?
++++++++++++++++++++++++
Measuring a car's speed by the miles it covers in an hour is
as obsolete as the buffalo nickel. Drivers need a speed measurement that
reflects our go-anywhere-fast lifestyle. We must replace miles per hour with
feet per second. Before it's too late.
Next time you're out driving in your Plymouth Lancet or
Lamborghini Inspector Rebus or whatever, look at the speedometer. What's the
number read? 30 miles per hour? 40 miles per hour? 90 miles per hour? 175 miles
per hour? What do those numbers even mean?
Miles-per-hour numbers have little to do with our bodies'
sensory response to forward motion. As much as the inner-ear's
spacial-orientation center knows, we could just as well measure a car's speed
in degrees Kelvin, or microfortnights or Hoppus feet.
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