## Sunday, August 9, 2009

### If you can't see my mirrors, I can't see you.

Returning from a weekend in Maine, I noticed a truck on the highway with the following sticker on the back:

Do you think this statement true and why it may or may not be so?

This story contains a hint. Read it to see why you should not be nose picking while driving.

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Alin Grin said...
This comment has been removed by the author.
Alin Grin said...

The meaning of the statement is comprehensible and basically it asks other drivers to
avoid driving in the truck driver's blind spot.
The statement is not physically accurate since having the truck's mirrors in the line of sight does not mean that you have the drivers eyes reflecting trough the mirror.
To be a bit more accurate the sticker should read:
"If you can't see my eyes in my mirrors. I can't see yours"
The driver's blind spot is narrower then what is defined in the above statement, since the driver can see other parts of the car and does not necessarily needs to establish eye contact with the other driver in order to see that there is a car.
In today's automotive market there are technologies which eliminate any significant blind spots altogether.
http://en.wikipedia.org/wiki/Blind_spot_(automobile)

Maria said...

One more goal for Alin.
Its a beautiful property of mirrors that every ray is reflected with the same angle it came with. Because of that, if you see anything or anyone in your mirror, this anything or anyone could see you by just traversing the light rays back.
Apparently in this truck there are no rear view mirror above the wheel. Only large side mirrors allow to see what happens behind. If you glance at these mirrors and see the driver, he could see you by looking back along the same ray. If you can't see either of these mirrors, driver can't see you.

Anonymous said...

I concur that this is only partly true, since a typical vehicle extends farther out than the position of someone's face inside the cabin. Hence, a truck driver could see the edge(s) of the vehicle without actually seeing the driver's eyes. Still, counting on that relatively small margin of space isn't wise.