Effect of speed on vision while driving

Visual acuity

One of the main effects of speed is to lower for the foreground objects that are unclear due to movements and vibrations in the car. A study has shown that this range of subcategory in the foreground of the sea increases by approximately 20 feet per increase 10 miles per hour in speed. So at 20 miles an hour, we can not see information clearly within 40 feet in advance of the car; at 60 miles per hour, not within 120 feet or more.

Let's imagine a driver with 20/20 visual acuity driving at 60 miles per hour. There is a highway sign ahead with three lines to write on it. This driver does not know the area – his memory can not be any help – he must read a sign. We have seen before that this driver can read 5 inches from 280 feet. We now know that when the car reaches a 120 foot level from icons, he can not see more details. He has only 160 feet, or 1.8 seconds, to read the icon.

A 20/60 perspective driver can not see the same symbol before reaching 93 feet – but his close-up image affects the same driver as the first driver. Will this driver be able to read a three-line message? The problem with diminished close vision explains why some drivers make emergency stop or slow down road cuts, especially in great ways. You must be aware of this risk and be prepared for the sudden action of other drivers. If you know the area you are running, short moments of signage will suffice – but remember strangers who do not know their way need longer.

Guaranteed, have investigated this problem, use the characters as much as possible, or write the written message as short as possible. Super highways always have labels with large and legible letters.


Your viewing area decreases with strength and speed. When you focus on one thing, the field of vision is zero – it's usually what happens with new drivers, because they tend to stare at what they believe to be important. The visual field is also reduced by speed. When stopped, the driver's range of vision can be as high as 190 degrees, but for the same person, the angle will be reduced to 40 degrees per 60 miles per hour. Therefore, whenever possible, highways are located above the roadway.

Distance Court

Good distance judgment depends on good visual acuity. As the speed is reduced, the distance value will also be affected when you drive fast.


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